Liquidsoap scripting language reference

The Source / … categories contain all functions that return sources. The Input functions are those which build elementary sources (playing files, synthesizing sound, etc.). The Output functions are those which take a source and register it for being streamed to the outside (file, soundcard, audio server, etc.). The Visualization functions are experimental ones that let you visualize in real-time some aspects of the audio stream. The Sound Processing functions are those which basically work on the source as a continuous audio stream. They would typically be mixers of streams, audio effects or analysis. Finally, Track Processing functions are basically all others, often having a behaviour that depends on or affects the extra information that liquidsoap puts in streams: track limits and metadata.

Source / Conversions
Source / Input
Source / Liquidsoap
Source / MIDI Processing
Source / Output
Source / Sound Processing
Source / Sound Synthesis
Source / Track Processing
Source / Video Processing
Source / Visualization
Bool
Control
Interaction
Liquidsoap
List
Math
Pair
String
System

Bool

`!=`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`<`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`<=`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`==`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`>`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`>=`

Comparison of comparable values.

Type:

('a, 'a) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type anything that is an orderable type)

`and`

Return the conjunction of its arguments

Type:

(bool, bool) -> bool

Arguments:

(unlabeled) (of type bool)
(unlabeled) (of type bool)

`not`

Returns the negation of its argument.

Type:

(bool) -> bool

Arguments:

(unlabeled) (of type bool)

`or`

Return the disjunction of its arguments

Type:

(bool, bool) -> bool

Arguments:

(unlabeled) (of type bool)
(unlabeled) (of type bool)

`random.bool`

Generate a random value.

Type:

() -> bool

Arguments:

Control

`add_timeout`

Call a function in N seconds. If the result of the function is positive or null, the task will be scheduled again after this amount of time (in seconds).

Type:

(?fast : bool, float, (() -> float)) -> unit

Arguments:

fast (of type bool, which defaults to true): Set to false if the execution of the code can take long in order to lower its priority below that of request resolutions and fast timeouts. This is only effective if you set a dedicated queue for fast tasks, see the “scheduler” settings for more details.
(unlabeled) (of type float)
(unlabeled) (of type () -> float)

`ignore`

Convert anything to unit, preventing warnings.

Type:

('a) -> unit

Arguments:

(unlabeled) (of type 'a)

Interaction

`add_skip_command`

Add a skip function to a source when it does not have one by default.

Type:

(source('a)) -> unit

Arguments:

(unlabeled) (of type source('a)): The source to attach the command to.

`audioscrobbler.nowplaying`

Submit a now playing song using the audioscrobbler protocol.

Type:

(user : string, password : string, ?host : string,
 ?port : int, ?length : bool, [string * string]) -> unit

Arguments:

user (of type string)
password (of type string)
host (of type string, which defaults to "post.audioscrobbler.com"): Host for audioscrobbling submissions.
port (of type int, which defaults to 80): Port for audioscrobbling submissions.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`audioscrobbler.submit`

Submit a played song using the audioscrobbler protocol.

Type:

(?source : string, user : string, password : string,
 ?host : string, ?port : int, ?length : bool,
 [string * string]) -> unit

Arguments:

source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
user (of type string)
password (of type string)
host (of type string, which defaults to "post.audioscrobbler.com"): Host for audioscrobbling submissions.
port (of type int, which defaults to 80): Port for audioscrobbling submissions.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`audioscrobbler.submit.full`

Submit songs using audioscrobbler, respecting the full protocol: First signal song as now playing when starting, and then submit song when it ends.

Type:

(user : string, password : string, ?host : string,
 ?port : int, ?source : string, ?length : bool,
 ?delay : float, ?force : bool, source('a)) -> source('a)

Arguments:

user (of type string)
password (of type string)
host (of type string, which defaults to "post.audioscrobbler.com")
port (of type int, which defaults to 80)
source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
delay (of type float, which defaults to 10.0): Submit song when there is only this delay left, in seconds.
force (of type bool, which defaults to false): If remaining time is null, the song will be assumed to be skipped or cuted, and not submitted. Set to zero to disable this behaviour.
(unlabeled) (of type source('a))

`harbor.http.static`

Serve a static path

Type:

(?port : int, ?path : string,
 ?content_type : ((string) -> string),
 ?headers : [string * string], string) -> unit

Arguments:

port (of type int, which defaults to 8000): Port for incoming harbor (http) connections.
path (of type string, which defaults to "/"): Base path
content_type (of type (string) -> string, which defaults to <fun>): Callback to specify Content-Type on a per file basis. Default: file.mime if compiled or file CLI if present.
headers (of type [string * string], which defaults to [("Access-Control-Allow-Origin", "*")]): Default response headers.
(unlabeled) (of type string): Local path to be served

`harbor.https.static`

Serve a static path

Type:

(?port : int, ?path : string,
 ?content_type : ((string) -> string),
 ?headers : [string * string], string) -> unit

Arguments:

port (of type int, which defaults to 8000): Port for incoming harbor (https) connections.
path (of type string, which defaults to "/"): Base path
content_type (of type (string) -> string, which defaults to <fun>): Callback to specify Content-Type on a per file basis. Default: file.mime if compiled or file CLI if present.
headers (of type [string * string], which defaults to [("Access-Control-Allow-Origin", "*")]): Default response headers.
(unlabeled) (of type string): Local path to be served

`http.delete`

Perform a full Http DELETE request and return (status,headers,data).

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`http.get`

Perform a full Http GET request and return (status,headers,data).

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`http.head`

Perform a full Http HEAD request and return (status,headers,data).

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`http.post`

Perform a full Http POST request and return (status,headers,data).

Type:

(?data : string, ?headers : [string * string],
 ?http_version : string, ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

data (of type string, which defaults to ""): POST data.
headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`http.put`

Perform a full Http PUT request and return (status,headers,data).

Type:

(?data : string, ?headers : [string * string],
 ?http_version : string, ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

data (of type string, which defaults to ""): POST data.
headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`http_codes`

List of HTTP response codes and statuses.

Type:

[string * string]

Arguments:

`http_response`

Create a HTTP response string

Type:

(?protocol : string, ?code : int,
 ?headers : [string * string], ?data : string) ->
() -> string

Arguments:

protocol (of type string, which defaults to "HTTP/1.1"): HTTP protocol used.
code (of type int, which defaults to 200): Response code.
headers (of type [string * string], which defaults to []): Response headers.
data (of type string, which defaults to ""): Response data

`http_response_stream`

Create a streamed HTTP response

Type:

(?protocol : string, ?code : int,
 ?headers : [string * string], data_len : 'a,
 data : (() -> string)) -> () -> string

Arguments:

protocol (of type string, which defaults to "HTTP/1.1"): HTTP protocol used.
code (of type int, which defaults to 200): Response code.
headers (of type [string * string], which defaults to []): Response headers.
data_len (of type 'a): Response length in bytes
data (of type () -> string): Response data

`https.delete`

Perform a full https DELETE request and return (status,headers),data.

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`https.get`

Perform a full https GET request and return (status,headers),data.

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`https.head`

Perform a full https HEAD request and return (status,headers),data.

Type:

(?headers : [string * string], ?http_version : string,
 ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`https.post`

Perform a full https POST request and return (status,headers),data.

Type:

(?data : string, ?headers : [string * string],
 ?http_version : string, ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

data (of type string, which defaults to ""): POST data.
headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`https.put`

Perform a full https PUT request and return (status,headers),data.

Type:

(?data : string, ?headers : [string * string],
 ?http_version : string, ?timeout : float, string) ->
(string * int * string) * [string * string] * string

Arguments:

data (of type string, which defaults to ""): POST data.
headers (of type [string * string], which defaults to []): Additional headers.
http_version (of type string, which defaults to "1.0"): Http request version.
timeout (of type float, which defaults to 10.0): Timeout for network operations.
(unlabeled) (of type string): Requested URL, e.g. “http://www.google.com:80/index.html”.

`icy.update_metadata`

Update metata on an icecast mountpoint using the ICY protocol.

Type:

(?host : string, ?port : int, ?user : string,
 ?password : string, ?mount : string, ?icy_id : int,
 ?protocol : string, ?encoding : string,
 ?headers : [string * string], [string * string]) -> unit

Arguments:

host (of type string, which defaults to "localhost")
port (of type int, which defaults to 8000)
user (of type string, which defaults to "source")
password (of type string, which defaults to "hackme")
mount (of type string, which defaults to ""): Source mount point. Mandatory when streaming to icecast.
icy_id (of type int, which defaults to 1): Shoutcast source ID. Only supported by Shoutcast v2.
protocol (of type string, which defaults to "http"): Protocol to use. One of: “icy”, “http” or “https”
encoding (of type string, which defaults to ""): Encoding used to send metadata, default (UTF-8) if empty.
headers (of type [string * string], which defaults to [("User-Agent", "Liquidsoap/1.4.4 (Unix; OCaml 4.10.0)")]): Additional headers.
(unlabeled) (of type [string * string])

`interactive.bool`

Read a boolean from an interactive input.

Type:

(string, bool) -> () -> bool

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type bool)

`interactive.float`

Read a float from an interactive input.

Type:

(string, float) -> () -> float

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type float)

`interactive.string`

Read a string from an interactive input.

Type:

(string, string) -> () -> string

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type string)

`lastfm.nowplaying`

Submit metadata to lastfm.fm using the audioscrobbler protocol (nowplaying mode).

Type:

(user : string, password : string, ?length : bool,
 [string * string]) -> unit

Arguments:

user (of type string)
password (of type string)
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`lastfm.submit`

Submit metadata to lastfm.fm using the audioscrobbler protocol.

Type:

(user : string, password : string, ?source : string,
 ?length : bool, [string * string]) -> unit

Arguments:

user (of type string)
password (of type string)
source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`lastfm.submit.full`

Submit songs to lastfm using audioscrobbler, respecting the full protocol: First signal song as now playing when starting, and then submit song when it ends.

Type:

(user : string, password : string, ?source : string,
 ?length : bool, ?delay : float, ?force : bool,
 source('a)) -> source('a)

Arguments:

user (of type string)
password (of type string)
source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
delay (of type float, which defaults to 10.0): Submit song when there is only this delay left, in seconds. If remaining time is less than this value, the song will be assumed to be skipped or cuted, and not submitted. Set to zero to disable this behaviour.
force (of type bool, which defaults to false): If remaining time is null, the song will be assumed to be skipped or cuted, and not submitted. Set to zero to disable this behaviour.
(unlabeled) (of type source('a))

`librefm.nowplaying`

Submit metadata to libre.fm using the audioscrobbler protocol (nowplaying mode).

Type:

(user : string, password : string, ?length : bool,
 [string * string]) -> unit

Arguments:

user (of type string)
password (of type string)
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`librefm.submit`

Submit metadata to libre.fm using the audioscrobbler protocol.

Type:

(user : string, password : string, ?source : string,
 ?length : bool, [string * string]) -> unit

Arguments:

user (of type string)
password (of type string)
source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
(unlabeled) (of type [string * string])

`librefm.submit.full`

Submit songs to librefm using audioscrobbler, respecting the full protocol: First signal song as now playing when starting, and then submit song when it ends.

Type:

(user : string, password : string, ?source : string,
 ?length : bool, ?delay : float, ?force : bool,
 source('a)) -> source('a)

Arguments:

user (of type string)
password (of type string)
source (of type string, which defaults to "broadcast"): Source for tracks. Should be one of: “broadcast”, “user”, “recommendation” or “unknown”. Since liquidsoap is intented for radio broadcasting, this is the default. Sources other than user don’t need duration to be set.
length (of type bool, which defaults to false): Try to submit length information. This operation can be CPU intensive. Value forced to true when used with the “user” source type.
delay (of type float, which defaults to 10.0): Submit song when there is only this delay left, in seconds. If remaining time is less than this value, the song will be assumed to be skipped or cuted, and not submitted. Set to zero to disable this behaviour.
force (of type bool, which defaults to false): If remaining time is null, the song will be assumed to be skipped or cuted, and not submitted. Set to zero to disable this behaviour.
(unlabeled) (of type source('a))

`metadata.float_getter`

Create a float getter from a metadata: this is a float, whose value can be changed with a metadata.

Type:

(float, string, source('a)) -> source('a) * (() -> float)

Arguments:

(unlabeled) (of type float): Initial value.
(unlabeled) (of type string): Metadata on which the value should be updated.
(unlabeled) (of type source('a)): Source containing the metadata.

`metadata.string_getter`

Create a string getter from a metadata: this is a string, whose value can be changed with a metadata.

Type:

(string, string, source('a)) ->
source('a) * (() -> string)

Arguments:

(unlabeled) (of type string): Initial value.
(unlabeled) (of type string): Metadata on which the value should be updated.
(unlabeled) (of type source('a)): Source containing the metadata.

`osc.bool`

Read from an OSC path.

Type:

(string, bool) -> () -> bool

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type bool): Initial value.

`osc.float`

Read from an OSC path.

Type:

(string, float) -> () -> float

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type float): Initial value.

`osc.float_pair`

Read from an OSC path.

Type:

(string, (float * float)) -> () -> float * float

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type float * float): Initial value.

`osc.int`

Read from an OSC path.

Type:

(string, int) -> () -> int

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type int): Initial value.

`osc.int_pair`

Read from an OSC path.

Type:

(string, (int * int)) -> () -> int * int

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type int * int): Initial value.

`osc.on_bool`

Type:

(string, ((bool) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type (bool) -> unit): Callback function.

`osc.on_float`

Type:

(string, ((float) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type (float) -> unit): Callback function.

`osc.on_float_pair`

Type:

(string, (((float * float)) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type ((float * float)) -> unit): Callback function.

`osc.on_int`

Type:

(string, ((int) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type (int) -> unit): Callback function.

`osc.on_int_pair`

Type:

(string, (((int * int)) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type ((int * int)) -> unit): Callback function.

`osc.on_string`

Type:

(string, ((string) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type (string) -> unit): Callback function.

`osc.on_string_pair`

Type:

(string, (((string * string)) -> unit)) -> unit

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type ((string * string)) -> unit): Callback function.

`osc.send_bool`

Send a value to an OSC client.

Type:

(host : string, port : int, string, bool) -> unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type bool): Value to send.

`osc.send_float`

Send a value to an OSC client.

Type:

(host : string, port : int, string, float) -> unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type float): Value to send.

`osc.send_float_pair`

Send a value to an OSC client.

Type:

(host : string, port : int, string, (float * float)) ->
unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type float * float): Value to send.

`osc.send_int`

Send a value to an OSC client.

Type:

(host : string, port : int, string, int) -> unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type int): Value to send.

`osc.send_int_pair`

Send a value to an OSC client.

Type:

(host : string, port : int, string, (int * int)) -> unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type int * int): Value to send.

`osc.send_string`

Send a value to an OSC client.

Type:

(host : string, port : int, string, string) -> unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type string): Value to send.

`osc.send_string_pair`

Send a value to an OSC client.

Type:

(host : string, port : int, string, (string * string)) ->
unit

Arguments:

host (of type string): OSC client address.
port (of type int): OSC client port.
(unlabeled) (of type string): OSC path.
(unlabeled) (of type string * string): Value to send.

`osc.string`

Read from an OSC path.

Type:

(string, string) -> () -> string

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type string): Initial value.

`osc.string_pair`

Read from an OSC path.

Type:

(string, (string * string)) -> () -> string * string

Arguments:

(unlabeled) (of type string): OSC path.
(unlabeled) (of type string * string): Initial value.

`print`

Print on standard output.

Type:

(?newline : bool, 'a) -> unit

Arguments:

newline (of type bool, which defaults to true): If true, a newline is added after displaying the value.
(unlabeled) (of type 'a)

`server.broadcast`

Restart all server clients waiting on the given condition

Type:

(('a * ('b * (() -> 'c)))) -> 'c

Arguments:

(unlabeled) (of type 'a * ('b * (() -> 'c))): condition

`server.condition`

Create a pair of functions (wait,(signal,broadcast)) used to suspend and resume server command execution. Used to write interactive server commands through server.wait, server.signal, server.broadcast and server.write.

Type:

() ->
(((() -> string)) -> string) *
((() -> unit) * (() -> unit))

Arguments:

`server.read`

Read a string from the client up-to a marker. Marker can be any string of regular expression. Should be used via the syntactic sugar: server.read <marker> : <varname> then <after> end

Type:

(((string) -> string), string) -> string

Arguments:

(unlabeled) (of type (string) -> string): function to run after write
(unlabeled) (of type string): Read marker

`server.readchars`

Read a string of fixed length from the client up-to a marker. Should be used via the syntactic sugar: server.readchars <len> : <varname> then <after> end

Type:

(((string) -> string), int) -> string

Arguments:

(unlabeled) (of type (string) -> string): function to run after write
(unlabeled) (of type int): Number of characters to read

`server.readline`

Read a line from the client. Should be used via the syntactic sugar: server.readline <varname> then <after> end

Type:

(((string) -> string)) -> string

Arguments:

(unlabeled) (of type (string) -> string): function to run after write

`server.register`

Type:

(?namespace : string, ?description : string,
 ?usage : string, string, ((string) -> string)) -> unit

Arguments:

namespace (of type string, which defaults to "")
description (of type string, which defaults to "No documentation available."): A description of your command.
usage (of type string, which defaults to "")
(unlabeled) (of type string)
(unlabeled) (of type (string) -> string)

`server.signal`

Restart one server client waiting on the given condition

Type:

(('a * ((() -> 'b) * 'c))) -> 'b

Arguments:

(unlabeled) (of type 'a * ((() -> 'b) * 'c)): condition

`server.wait`

Wait on a server condition. Used to write interactive server command. Should be used via the syntactic sugar: server.wait <condition> then <after> end

Type:

(((((() -> string)) -> string) * 'a), (() -> string)) ->
string

Arguments:

(unlabeled) (of type (((() -> string)) -> string) * 'a): condition
(unlabeled) (of type () -> string): code to execute when resuming

`server.write`

Execute a partial write while executing a server command. Should be used via the syntactic sugar: server.write <string> then <after> end

Type:

((() -> string), string) -> string

Arguments:

(unlabeled) (of type () -> string): function to run after write
(unlabeled) (of type string): string to write

Liquidsoap

`add_decoder`

Register an external decoder. The encoder should output in WAV format to his standard output (stdout) and read data from its standard input (stdin).

Type:

(name : string, description : string, ?mimes : [string],
 test : ((string) -> int), string) -> unit

Arguments:

name (of type string): Format/decoder’s name.
description (of type string): Description of the decoder.
mimes (of type [string], which defaults to []): List of mime types supported by this decoder for decoding streams.
test (of type (string) -> int): Function used to determine if a file should be decoded by the decoder. Returned values are: 0: no decodable audio, -1: decodable audio but number of audio channels unknown, x: fixed number of decodable audio channels.
(unlabeled) (of type string): Process to start.

`add_metadata_resolver`

Type:

(string, ((string) -> [string * string])) -> unit

Arguments:

(unlabeled) (of type string): Format/resolver’s name.
(unlabeled) (of type (string) -> [string * string]): Process to start. The function takes the format and filename as argument and returns a list of (name,value) fields.

`add_oblivious_decoder`

Register an external file decoder. The encoder should output in WAV format to his standard output (stdout) and read data from the file it receives. The estimated remaining duration for this decoder will be unknown until the buffer last seconds of the file. If possible, it is recommended to decode from stdin and use add_decoder.

Type:

(name : string, description : string,
 test : ((string) -> int), ?buffer : float,
 ((string) -> string)) -> unit

Arguments:

name (of type string): Format/decoder’s name.
description (of type string): Description of the decoder.
test (of type (string) -> int): Function used to determine if a file should be decoded by the decoder. Returned values are: 0: no decodable audio, -1: decodable audio but number of audio channels unknown, x: fixed number of decodable audio channels.
buffer (of type float, which defaults to 5.0)
(unlabeled) (of type (string) -> string): Process to start. The function takes the filename as argument and returns the process to start.

`add_playlist_parser`

Type:

(format : string, strict : bool,
 ((?pwd : string, string) ->
  [[string * string] * string])) -> unit

Arguments:

format (of type string): Playlist format. If possible, a mime-type.
strict (of type bool): True if playlist format can be detected unambiguously.
(unlabeled) (of type (?pwd : string, string) -> [[string * string] * string]): Playlist parser

`add_protocol`

Type:

(?temporary : bool, ?static : bool, ?syntax : string,
 ?doc : string, string,
 ((rlog : ((string) -> unit), maxtime : float, string) ->
  [string])) -> unit

Arguments:

temporary (of type bool, which defaults to false): if true, file is removed when it is finished.
static (of type bool, which defaults to false): if true, then requests can be resolved once and for all. Typically, static protocols can be used to create infallible sources.
syntax (of type string, which defaults to "Undocumented"): URI syntax.
doc (of type string, which defaults to "Undocumented"): Protocol documentation.
(unlabeled) (of type string): Protocol name. Resolver will be called on uris of the form: <protocol name>:....
(unlabeled) (of type (rlog : ((string) -> unit), maxtime : float, string) -> [string]): Protocol resolver. Receives a function to log protocol resolution, the <arg> in <protocol name>:<arg> and the max delay that resolution should take.

`audio.channels`

Channels for audio.

Type:

() -> int

Arguments:

`audio.samplerate`

Samplerate for audio.

Type:

() -> int

Arguments:

`bool_getter`

Identity function over bool getters. This is useful to make types explicit.

Type:

({bool}) -> {bool}

Arguments:

(unlabeled) (of type {bool})

`clock`

Assign a new clock to the given source (and to other time-dependent sources) and return the source. It is a conveniency wrapper around clock.assign_new(), allowing more concise scripts in some cases.

Type:

(?sync : bool, ?id : string, source('a)) -> source('a)

Arguments:

sync (of type bool, which defaults to true): When false, do not synchronize the clock on regular wallclock time, but try to run as fast as possible (CPU burning mode).
id (of type string, which defaults to "")
(unlabeled) (of type source('a))

`clock.assign_new`

Create a new clock and assign it to a list of sources.

Type:

(?id : string, ?sync : bool, [source('a)]) -> unit

Arguments:

id (of type string, which defaults to ""): Identifier for the new clock. The default empty string means that the identifier of the first source will be used.
sync (of type bool, which defaults to true): Do not synchronize the clock on regular wallclock time, but try to run as fast as possible (CPU burning mode).
(unlabeled) (of type [source('a)]): List of sources to which the new clock will be assigned

`clock.log`

Create a log of clock times for all the clocks initially present. The log is in a simple format which you can directly use with gnuplot.

Type:

(?delay : float, ?interval : float, string) -> unit

Arguments:

delay (of type float, which defaults to 0.0): Delay before setting up the clock logger. This should be used to ensure that the logger starts only after the clocks are created.
interval (of type float, which defaults to 1.0): Polling interval.
(unlabeled) (of type string): Path of the log file.

`clock.status`

Get the current time for all allocated clocks.

Type:

() -> [string * int]

Arguments:

`clock.unify`

Enforce that a list of sources all belong to the same clock.

Type:

([source('a)]) -> unit

Arguments:

(unlabeled) (of type [source('a)])

`configure.bindir`

Liquidsoap’s Internal script directory.

Type:

string

Arguments:

`configure.default_font`

Liquidsoap’s default font file.

Type:

string

Arguments:

`configure.libdir`

Liquidsoap’s library directory.

Type:

string

Arguments:

`configure.logdir`

Liquidsoap’s logging directory.

Type:

string

Arguments:

`configure.rundir`

Liquidsoap’s PID file directory.

Type:

string

Arguments:

`enable_external_faad_decoder`

Enable or disable external FAAD (AAC/AAC+/M4A) decoders. Does not work on Win32. Please note that built-in support for faad is available in liquidsoap if compiled and should be preferred over the external decoder.

Type:

() -> unit

Arguments:

`enable_external_ffmpeg_decoder`

Enable ffmpeg decoder.

Type:

() -> unit

Arguments:

`enable_external_flac_decoder`

Enable external FLAC decoders. Please note that built-in support for FLAC is available in liquidsoap if compiled and should be preferred over the external decoder.

Type:

() -> unit

Arguments:

`enable_external_mpc_decoder`

Enable external Musepack decoder.

Type:

() -> unit

Arguments:

`enable_replaygain_metadata`

Enable replay gain metadata resolver. This resolver will process any file decoded by liquidsoap and add a replay_gain metadata when this value could be computed. For a finer-grained replay gain processing, use the replay_gain protocol.

Type:

(?delay : float, ?extract_replaygain : string) -> unit

Arguments:

delay (of type float, which defaults to -1.0): Maximum delay for extracting metadata
extract_replaygain (of type string, which defaults to "/usr/local/share/liquidsoap/1.4.4/bin/extract-replaygain"): The extraction program

`encoder.content_type`

Return the content-type (mime) of an encoder, if known.

Type:

(format('a)) -> string

Arguments:

(unlabeled) (of type format('a))

`encoder.extension`

Return the file extension of an encoder, if known.

Type:

(format('a)) -> string

Arguments:

(unlabeled) (of type format('a))

`file.mime`

Get the MIME type of a file, according to libmagic.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`float_getter`

Identity function over float getters. This is useful to make types explicit.

Type:

({float}) -> {float}

Arguments:

(unlabeled) (of type {float})

`for`

A “for” loop: call multiple times a function with increasing integers as arguments, between specified bounds. For instance, for(5, 8, f) is equivalent to f(5); f(6); f(7); f(8).

Type:

(int, int, ((int) -> unit)) -> unit

Arguments:

(unlabeled) (of type int, which defaults to ???): First number
(unlabeled) (of type int, which defaults to ???): Last number
(unlabeled) (of type (int) -> unit, which defaults to ???): Function to be called

`garbage_collect`

Trigger full major garbage collection.

Type:

() -> unit

Arguments:

`get`

Get a setting’s value.

Type:

(default : 'a, string) -> 'a
where 'a is unit, bool, int, float, string or [string]

Arguments:

default (of type anything that is unit, bool, int, float, string or [string])
(unlabeled) (of type string)

`harbor.http.register`

Register a HTTP handler on the harbor. The given function receives as argument the full requested uri (e.g. “foo?var=bar”), http protocol version, possible input data and the list of HTTP headers and returns the answer sent to the client, including HTTP headers. Registered uri can be regular expressions (e.g. “.+.php”) and can override default metadata handlers. Response is a string getter, i.e. either of type string or type ()->string. In the later case, getter function will be called until it returns an empty string.

Type:

(port : int, method : string, string,
 ((protocol : string, data : string,
   headers : [string * string], string) -> {string})) ->
unit

Arguments:

port (of type int): Port to server.
method (of type string): Accepted method
(unlabeled) (of type string): URI to serve.
(unlabeled) (of type (protocol : string, data : string, headers : [string * string], string) -> {string}): Function to execute. method argument is “PUT” or “GET”, protocol argument is “HTTP/1.1” or “HTTP/1.0” etc., data argument contains data passed in case of a PUT request, and “” otherwise. headers argument contains the HTTP headers. Unlabeled argument contains the requested URI.

`harbor.http.remove`

Remove a registered HTTP handler on the harbor.

Type:

(method : string, port : int, string) -> unit

Arguments:

method (of type string): Method served.
port (of type int): Port to server.
(unlabeled) (of type string): URI served.

`harbor.https.register`

Register a HTTPS handler on the harbor. The given function receives as argument the full requested uri (e.g. “foo?var=bar”), http protocol version, possible input data and the list of HTTP headers and returns the answer sent to the client, including HTTP headers. Registered uri can be regular expressions (e.g. “.+.php”) and can override default metadata handlers. Response is a string getter, i.e. either of type string or type ()->string. In the later case, getter function will be called until it returns an empty string.

Type:

(port : int, method : string, string,
 ((protocol : string, data : string,
   headers : [string * string], string) -> {string})) ->
unit

Arguments:

port (of type int): Port to server.
method (of type string): Accepted method
(unlabeled) (of type string): URI to serve.
(unlabeled) (of type (protocol : string, data : string, headers : [string * string], string) -> {string}): Function to execute. method argument is “PUT” or “GET”, protocol argument is “HTTP/1.1” or “HTTP/1.0” etc., data argument contains data passed in case of a PUT request, and “” otherwise. headers argument contains the HTTP headers. Unlabeled argument contains the requested URI.

`harbor.https.remove`

Remove a registered HTTPS handler on the harbor.

Type:

(method : string, port : int, string) -> unit

Arguments:

method (of type string): Method served.
port (of type int): Port to server.
(unlabeled) (of type string): URI served.

`int_getter`

Identity function over int getters. This is useful to make types explicit.

Type:

({int}) -> {int}

Arguments:

(unlabeled) (of type {int})

`liquidsoap.version`

Liquidsoap version string.

Type:

string

Arguments:

`log`

Log a message.

Type:

(?label : string, ?level : int, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
level (of type int, which defaults to 3)
(unlabeled) (of type string)

`log.critical`

Log a critical message

Type:

(?label : string, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
(unlabeled) (of type string)

`log.debug`

Log a debug message

Type:

(?label : string, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
(unlabeled) (of type string)

`log.important`

Log an important message

Type:

(?label : string, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
(unlabeled) (of type string)

`log.info`

Log a normal message

Type:

(?label : string, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
(unlabeled) (of type string)

`log.severe`

Log a severe message

Type:

(?label : string, string) -> unit

Arguments:

label (of type string, which defaults to "lang")
(unlabeled) (of type string)

`metadata.export`

Filter-out internal metadata.

Type:

([string * string]) -> [string * string]

Arguments:

(unlabeled) (of type [string * string])

`mutexify`

Protect functions with a mutex to avoid concurrent calls, return original value otherwise.

Type:

('a) -> 'a

Arguments:

(unlabeled) (of type 'a)

`playlist.parse`

Try to parse a local playlist. Return a list of (metadata,URI) items, where metadata is a list of (key,value) bindings.

Type:

(?path : string, ?mime : string, string) ->
[[string * string] * string]

Arguments:

path (of type string, which defaults to ""): Default path for files.
mime (of type string, which defaults to ""): Mime type for the playlist
(unlabeled) (of type string)

`process_uri`

Create a process: uri, replacing : with $(colon)

Type:

(extname : 'a, ?uri : string, string) -> string

Arguments:

extname (of type 'a): Output file extension (with no leading ‘.’)
uri (of type string, which defaults to ""): Input uri
(unlabeled) (of type string): Command line to execute

`ref.get`

Obtain the value stored in a reference. This is an alias to !.

Type:

(ref('a)) -> 'a

Arguments:

(unlabeled) (of type ref('a))

`ref.getter`

Create a getter from a reference.

Type:

(ref('a)) -> () -> 'a

Arguments:

(unlabeled) (of type ref('a))

`ref.set`

Change the value stored in a reference. This is an alias to :=.

Type:

(ref('a), 'a) -> unit

Arguments:

(unlabeled) (of type ref('a))
(unlabeled) (of type 'a)

`register`

Type:

(name : string, ?descr : string,
 ?on_change : (('a) -> unit), string, 'a) -> unit
where 'a is unit, bool, int, float, string or [string]

Arguments:

name (of type string): Settings name
descr (of type string, which defaults to ""): Settings description
on_change (of type ('a) -> unit where 'a is unit, bool, int, float, string or [string], which defaults to <fun>): Callback executed when the setting is changed.
(unlabeled) (of type string): Setting key
(unlabeled) (of type anything that is unit, bool, int, float, string or [string]): Setting initial value

`register_flow`

Type:

(?server : string, ?user : string, ?password : string,
 ?email : string, radio : string, website : string,
 description : string, genre : string,
 streams : [string * string], source('a)) -> source('a)

Arguments:

server (of type string, which defaults to "")
user (of type string, which defaults to "default")
password (of type string, which defaults to "default")
email (of type string, which defaults to "")
radio (of type string): Name of the radio.
website (of type string): URL of the website of the radio.
description (of type string): Description of the radio.
genre (of type string): Genre of the radio (rock or rap or etc.).
streams (of type [string * string]): List of streams for the radio described by a pair of strings consisting of the format of the stream and the url of the stream. The format should be of the form “ogg/128k” consisting of the codec and the bitrate, separated by “/”.
(unlabeled) (of type source('a))

`request.create`

Create a request. Creation may fail if there is no available RID, which cannot be detected currently: in that case one will obtain a request that will fail to be resolved.

Type:

(?indicators : [string], ?persistent : bool, string) ->
request('a)

Arguments:

indicators (of type [string], which defaults to [])
persistent (of type bool, which defaults to false)
(unlabeled) (of type string)

`request.create.raw`

Create a raw request, i.e. for files that should not be decoded for streaming. Creation may fail if there is no available RID, which cannot be detected currently: in that case one will obtain a request that will fail to be resolved.

Type:

(?indicators : [string], ?persistent : bool, string) ->
request(audio=0, video=0, midi=0)

Arguments:

indicators (of type [string], which defaults to [])
persistent (of type bool, which defaults to false)
(unlabeled) (of type string)

`request.destroy`

Destroying a request causes any temporary associated file to be deleted, and releases its RID. Persistent requests resist to destroying, unless forced.

Type:

(?force : bool, request('a)) -> unit

Arguments:

force (of type bool, which defaults to false): Destroy the request even if it is persistent.
(unlabeled) (of type request('a))

`request.duration`

Compute the duration in seconds of audio data contained in a request. The computation may be expensive. Returns -1. if computation failed, typically if the file was not recognized as valid audio.

Type:

(string) -> float

Arguments:

(unlabeled) (of type string)

`request.filename`

Return a valid local filename if the request is ready, and the empty string otherwise.

Type:

(request('a)) -> string

Arguments:

(unlabeled) (of type request('a))

`request.log`

Get log data associated to a request.

Type:

(request('a)) -> string

Arguments:

(unlabeled) (of type request('a))

`request.metadata`

Get the metadata associated to a request.

Type:

(request('a)) -> [string * string]

Arguments:

(unlabeled) (of type request('a))

`request.ready`

Check if a request is ready, i.e. is associated to a valid local file. Unless the initial URI was such a file, a request has to be resolved before being ready.

Type:

(request('a)) -> bool

Arguments:

(unlabeled) (of type request('a))

`request.resolve`

Resolve a request, i.e. attempt to get a valid local file. The operation can take some time. Return true if the resolving was successful, false otherwise (timeout or invalid URI).

Type:

(?timeout : float, request('a)) -> bool

Arguments:

timeout (of type float, which defaults to 30.0): Limit in seconds to the duration of the resolving.
(unlabeled) (of type request('a))

`request.uri`

Initial URI of a reuqest.

Type:

(request('a)) -> string

Arguments:

(unlabeled) (of type request('a))

`server.execute`

Execute a liquidsoap server command.

Type:

(string, ?string) -> [string]

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type string, which defaults to "")

`set`

Change some setting. Use liquidsoap --conf-descr and liquidsoap --conf-descr-key KEY on the command-line to get some information about available settings.

Type:

(string, 'a) -> unit
where 'a is unit, bool, int, float, string or [string]

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type anything that is unit, bool, int, float, string or [string])

`source.fallible`

Indicate if a source may fail, i.e. may not be ready to stream.

Type:

(source('a)) -> bool

Arguments:

(unlabeled) (of type source('a))

`source.id`

Get one source’s identifier.

Type:

(source('a)) -> string

Arguments:

(unlabeled) (of type source('a))

`source.init`

Simultaneously initialize sources, return the sublist of sources that failed to initialized.

Type:

([source(audio=*, video=*, midi=*)]) ->
[source(audio=*, video=*, midi=*)]

Arguments:

(unlabeled) (of type [source(audio=*, video=*, midi=*)])

`source.is_ready`

Indicate if a source is ready to stream, or currently streaming.

Type:

(source('a)) -> bool

Arguments:

(unlabeled) (of type source('a))

`source.remaining`

Estimation of remaining time in the current track.

Type:

(source('a)) -> float

Arguments:

(unlabeled) (of type source('a))

`source.seek`

Seek forward, in seconds. Returns the amount of time effectively seeked.

Type:

(source('a), float) -> float

Arguments:

(unlabeled) (of type source('a))
(unlabeled) (of type float)

`source.shutdown`

Desactivate a source.

Type:

(source('a)) -> unit

Arguments:

(unlabeled) (of type source('a))

`source.skip`

Skip to the next track.

Type:

(source('a)) -> unit

Arguments:

(unlabeled) (of type source('a))

`source.time`

Get a source’s time, based on its assigned clock

Type:

(source('a)) -> float

Arguments:

(unlabeled) (of type source('a))

`string_getter`

Identity function over string getters. This is useful to make types explicit.

Type:

({string}) -> {string}

Arguments:

(unlabeled) (of type {string})

`to_bool_getter`

Return a function from a bool getter

Type:

({bool}) -> () -> bool

Arguments:

(unlabeled) (of type {bool})

`to_float_getter`

Return a function from a float getter

Type:

({float}) -> () -> float

Arguments:

(unlabeled) (of type {float})

`to_int_getter`

Return a function from a int getter

Type:

({int}) -> () -> int

Arguments:

(unlabeled) (of type {int})

`to_string_getter`

Return a function from a string getter

Type:

({string}) -> () -> string

Arguments:

(unlabeled) (of type {string})

Liquidsoap

`ref.make`

Create a reference, i.e. a value that can be modified. This is an alias to ref.

Type:

('a) -> ref('a)

Arguments:

(unlabeled) (of type 'a)

List

`_[_]`

l[k] returns the first v such that (k,v) is in the list l (or “” if no such v exists).

Type:

(string, [string * string]) -> string

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type [string * string])

`list.add`

Add an element at the top of a list.

Type:

('a, ['a]) -> ['a]

Arguments:

(unlabeled) (of type 'a)
(unlabeled) (of type ['a])

`list.append`

Catenate two lists.

Type:

(['a], ['a]) -> ['a]

Arguments:

(unlabeled) (of type ['a])
(unlabeled) (of type ['a])

`list.assoc`

Generalized l[k] with default value.

Type:

(default : 'a, 'b, ['b * 'a]) -> 'a
where 'b is an orderable type

Arguments:

default (of type 'a): Default value if key does not exist
(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type ['b * 'a] where 'b is an orderable type)

`list.case`

Define a function by case analysis, depending on whether a list is empty or not.

Type:

('a, (('b, ['b]) -> 'a), ['b]) -> 'a

Arguments:

(unlabeled) (of type 'a): Result when the list is empty.
(unlabeled) (of type ('b, ['b]) -> 'a): Result when the list it non-empty.
(unlabeled) (of type ['b]): List to perform case analysis on.

`list.filter`

Filter a list according to a filtering function.

Type:

((('a) -> bool), ['a]) -> ['a]

Arguments:

(unlabeled) (of type ('a) -> bool)
(unlabeled) (of type ['a])

`list.filter_assoc`

list.filter_assoc(key,l) returns all the elements of the form (key, value) from l.

Type:

('a, ['a * 'b]) -> ['a * 'b]
where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type): Key to look for
(unlabeled) (of type ['a * 'b] where 'a is an orderable type): List of pairs (key,value)

`list.fold`

Fold a function on every element of a list: list.fold(f,x1,[e1,..,en]) is f(…f(f(x1,e1),e2)…,en).

Type:

((('a, 'b) -> 'a), 'a, ['b]) -> 'a

Arguments:

(unlabeled) (of type ('a, 'b) -> 'a): Function f for which f(x,e) which will be called on every element e with the current value of x, returning the new value of x.
(unlabeled) (of type 'a): Initial value x1, to be updated by successive calls of f(x,e).
(unlabeled) (of type ['b])

`list.hd`

Return the head (first element) of a list, or ‘default’ if the list is empty.

Type:

(default : 'a, ['a]) -> 'a

Arguments:

default (of type 'a): Default value if key does not exist
(unlabeled) (of type ['a])

`list.iter`

Call a function on every element of a list.

Type:

((('a) -> unit), ['a]) -> unit

Arguments:

(unlabeled) (of type ('a) -> unit)
(unlabeled) (of type ['a])

`list.length`

Get the length of a list, i.e. its number of elements.

Type:

(['a]) -> int

Arguments:

(unlabeled) (of type ['a])

`list.map`

Map a function on every element of a list.

Type:

((('a) -> 'b), ['a]) -> ['b]

Arguments:

(unlabeled) (of type ('a) -> 'b)
(unlabeled) (of type ['a])

`list.mapi`

Map a function on every element of a list, along with its index.

Type:

(((int, 'a) -> 'b), ['a]) -> ['b]

Arguments:

(unlabeled) (of type (int, 'a) -> 'b)
(unlabeled) (of type ['a])

`list.mem`

Check if an element belongs to a list.

Type:

('a, ['a]) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type)
(unlabeled) (of type ['a] where 'a is an orderable type)

`list.mem_assoc`

list.mem_assoc(key,l) returns true if l contains a pair (key,value)

Type:

('a, ['a * 'b]) -> bool where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type): Key to look for
(unlabeled) (of type ['a * 'b] where 'a is an orderable type): List of pairs (key,value)

`list.nth`

Get the n-th element of a list (the first element is at position 0), or’default’ if element does not exist.

Type:

(default : 'a, ['a], int) -> 'a

Arguments:

default (of type 'a): Default value if key does not exist
(unlabeled) (of type ['a])
(unlabeled) (of type int)

`list.randomize`

Shuffle the content of a list.

Type:

(['a]) -> ['a]

Arguments:

(unlabeled) (of type ['a])

`list.remove`

Remove a the first occurence of a value from a list.

Type:

('a, ['a]) -> ['a]

Arguments:

(unlabeled) (of type 'a)
(unlabeled) (of type ['a])

`list.remove_assoc`

Remove the first pair from an associative list.

Type:

('a, ['a * 'c]) -> ['a * 'c]
where 'a is an orderable type

Arguments:

(unlabeled) (of type anything that is an orderable type): Key of pair to be removed
(unlabeled) (of type ['a * 'c] where 'a is an orderable type): List of pairs (key,value)

`list.rev`

Revert list order.

Type:

(['a]) -> ['a]

Arguments:

(unlabeled) (of type ['a])

`list.sort`

Sort a list according to a comparison function.

Type:

((('a, 'a) -> int), ['a]) -> ['a]

Arguments:

(unlabeled) (of type ('a, 'a) -> int)
(unlabeled) (of type ['a])

`list.tl`

Return the list without its first element.

Type:

(['a]) -> ['a]

Arguments:

(unlabeled) (of type ['a])

Math

`*`

Multiplication of numbers.

Type:

('a, 'a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)
(unlabeled) (of type anything that is a number type)

`+`

Addition of numbers.

Type:

('a, 'a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)
(unlabeled) (of type anything that is a number type)

`-`

Substraction of numbers.

Type:

('a, 'a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)
(unlabeled) (of type anything that is a number type)

`/`

Division of numbers.

Type:

('a, 'a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)
(unlabeled) (of type anything that is a number type)

`abs`

Absolute value.

Type:

('a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)

`acos`

Arc cosine. The argument must fall within the range [-1.0, 1.0]. Result is in radians and is between 0.0 and pi.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`asin`

Arc sine. The argument must fall within the range [-1.0, 1.0]. Result is in radians and is between -pi/2 and pi/2.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`atan`

Arc tangent. Result is in radians and is between -pi/2 and pi/2.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`bool_of_float`

Convert a float to a bool.

Type:

(float) -> bool

Arguments:

(unlabeled) (of type float)

`bool_of_int`

Convert an int to a bool.

Type:

(int) -> bool

Arguments:

(unlabeled) (of type int)

`cos`

Cosine. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`cosh`

Hyperbolic cosine. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`dB_of_lin`

Convert linear scale into decibels.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`exp`

Exponential.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`float_of_int`

Convert an int to a float.

Type:

(int) -> float

Arguments:

(unlabeled) (of type int)

`int_of_float`

Convert a float to a int.

Type:

(float) -> int

Arguments:

(unlabeled) (of type float)

`lin_of_dB`

Convert decibels into linear scale.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`log_10`

Base 10 logarithm.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`log_e`

Natural logarithm.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`lsl`

Logical shift left.

Type:

(int, int) -> int

Arguments:

(unlabeled) (of type int): Number to shift.
(unlabeled) (of type int): Number of bits to shift.

`lsr`

Logical shift right.

Type:

(int, int) -> int

Arguments:

(unlabeled) (of type int): Number to shift.
(unlabeled) (of type int): Number of bits to shift.

`mkfade`

Make a fade function based on a source’s clock.

Type:

(?type : string, ?start : float, ?stop : float,
 ?duration : float, ?on_done : (() -> unit), source('a)) ->
() -> float

Arguments:

type (of type string, which defaults to "lin"): Fade shape. One of: “sin”, “exp”, “log”, “lin”
start (of type float, which defaults to 0.0): Start value.
stop (of type float, which defaults to 1.0): Stop value.
duration (of type float, which defaults to 3.0): Duration in seconds.
on_done (of type () -> unit, which defaults to <fun>): Function to execute when the fade is finished
(unlabeled) (of type source('a))

`mod`

Integer remainder. If y is not zero, x == (x / y) * y + x mod y, and abs(x mod y) <= abs(y)-1.

Type:

(int, int) -> int

Arguments:

(unlabeled) (of type int)
(unlabeled) (of type int)

`pow`

Exponentiation of numbers.

Type:

('a, 'a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)
(unlabeled) (of type anything that is a number type)

`random.float`

Generate a random value.

Type:

(?min : float, ?max : float) -> float

Arguments:

min (of type float, which defaults to -1000000.0)
max (of type float, which defaults to 1000000.0)

`random.int`

Generate a random value.

Type:

(?min : int, ?max : int) -> int

Arguments:

min (of type int, which defaults to -536870911)
max (of type int, which defaults to 536870912)

`sin`

Sine. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`sinh`

Hyperbolic sine. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`sqrt`

Square root.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`tan`

Tangent. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`tanh`

Hyperbolic tangent. Argument is in radians.

Type:

(float) -> float

Arguments:

(unlabeled) (of type float)

`~-`

Returns the opposite of its argument.

Type:

('a) -> 'a where 'a is a number type

Arguments:

(unlabeled) (of type anything that is a number type)

Other

Output

`output.external.ffmpeg`

Output to ffmpeg.

Type:

(?id : string, ?show_command : bool, ?flush : bool,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?reopen_delay : float,
 ?reopen_on_metadata : bool, ?reopen_when : (() -> bool),
 ?start : bool, string, source(audio=2, video=1, midi=0)) ->
active_source(audio=2, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
show_command (of type bool, which defaults to false)
flush (of type bool, which defaults to false): Perform a flush after each write.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
reopen_delay (of type float, which defaults to 120.0): Prevent re-opening within that delay, in seconds.
reopen_on_metadata (of type bool, which defaults to false): Re-open on every new metadata information.
reopen_when (of type () -> bool, which defaults to {false}): When should the output be re-opened.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type string)
(unlabeled) (of type source(audio=2, video=1, midi=0))

`output.file.hls.ffmpeg`

Output a HLS playlist using ffmpeg

Type:

(?id : string, ?flush : bool, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?reopen_delay : float, ?reopen_on_metadata : bool,
 ?reopen_when : (() -> bool), ?start : bool,
 ?playlist : string, directory : string, source(audio=2,
 video=1, midi=0)) -> active_source(audio=2, video=1,
midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
flush (of type bool, which defaults to false): Perform a flush after each write.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
reopen_delay (of type float, which defaults to 120.0): Prevent re-opening within that delay, in seconds.
reopen_on_metadata (of type bool, which defaults to false): Re-open on every new metadata information.
reopen_when (of type () -> bool, which defaults to {false}): When should the output be re-opened.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
playlist (of type string, which defaults to "stream.m3u8"): Playlist name
directory (of type string): Directory to write to
(unlabeled) (of type source(audio=2, video=1, midi=0))

`output.youtube.live.ffmpeg`

Stream to youtube.

Type:

(?id : string, ?flush : bool, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?reopen_delay : float, ?reopen_on_metadata : bool,
 ?reopen_when : (() -> bool), ?start : bool,
 ?url : string, ?bitrate : string, ?quality : string,
 key : string, source(audio=2, video=1, midi=0)) ->
active_source(audio=2, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
flush (of type bool, which defaults to false): Perform a flush after each write.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
reopen_delay (of type float, which defaults to 120.0): Prevent re-opening within that delay, in seconds.
reopen_on_metadata (of type bool, which defaults to false): Re-open on every new metadata information.
reopen_when (of type () -> bool, which defaults to {false}): When should the output be re-opened.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
url (of type string, which defaults to "rtmp://a.rtmp.youtube.com/live2"): URL to stream to
bitrate (of type string, which defaults to "2500"): Bitrate of the video (in kbps)
quality (of type string, which defaults to "medium"): Quality of the video (low / medium / high)
key (of type string): Your secret youtube key
(unlabeled) (of type source(audio=2, video=1, midi=0))

Pair

`fst`

Get the first component of a pair.

Type:

(('a * 'b)) -> 'a

Arguments:

(unlabeled) (of type 'a * 'b)

`snd`

Get the second component of a pair.

Type:

(('a * 'b)) -> 'b

Arguments:

(unlabeled) (of type 'a * 'b)

Source / Conversions

`audio_to_stereo`

Convert any kind of audio source into a stereo source.

Type:

(?id : string, source(audio=*+1, video=0, midi=0)) ->
source(audio=2, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio=*+1, video=0, midi=0))

`drop_audio`

Drop all audio channels of a stream.

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio=0, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`drop_midi`

Drop all midi channels of a stream.

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`drop_video`

Drop all video channels of a stream.

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video=0, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`id`

Does not do anything, simply forwards its input stream.

Type:

(?id : string, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source('a))

`mean`

Produce mono audio by taking the mean of all audio channels.

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio=1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`mux_audio`

Mux an audio stream into an audio-free stream.

Type:

(?id : string, audio : source(audio='#a, video=0,
 midi=0), ?mode : string, source(audio=0, video='#b,
 midi='#c)) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
audio (of type source(audio='#a, video=0, midi=0))
mode (of type string, which defaults to "master"): Track mode, specifying where the tracks are taken from (none|master|auxiliary|both). Modes other than "none" might induce a slight desynchronization between sources.
(unlabeled) (of type source(audio=0, video='#b, midi='#c))

`mux_mono`

Mux a mono audio stream into another stream.

Type:

(?id : string, ?mode : string, mono : source(audio=1,
 video=0, midi=0), source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mode (of type string, which defaults to "master"): Track mode, specifying where the tracks are taken from (none|master|auxiliary|both). Modes other than "none" might induce a slight desynchronization between sources.
mono (of type source(audio=1, video=0, midi=0))
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`mux_stereo`

Mux a stereo audio stream into another stream.

Type:

(?id : string, ?mode : string, stereo : source(audio=2,
 video=0, midi=0), source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a+2, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mode (of type string, which defaults to "master"): Track mode, specifying where the tracks are taken from (none|master|auxiliary|both). Modes other than "none" might induce a slight desynchronization between sources.
stereo (of type source(audio=2, video=0, midi=0))
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`mux_video`

Add video channnels to a stream.

Type:

(?id : string, ?mode : string, video : source(audio=0,
 video='#a, midi=0), source(audio='#b, video=0,
 midi='#c)) -> source(audio='#b, video='#a, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mode (of type string, which defaults to "master"): Track mode, specifying where the tracks are taken from (none|master|auxiliary|both). Modes other than "none" might induce a slight desynchronization between sources.
video (of type source(audio=0, video='#a, midi=0))
(unlabeled) (of type source(audio='#b, video=0, midi='#c))

`stereo.left`

Extract the left channel of a stereo source

Type:

(source(audio=2, video=0, midi=0)) -> source(audio=1,
video=0, midi=0)

Arguments:

(unlabeled) (of type source(audio=2, video=0, midi=0)): Source to extract from

`stereo.right`

Extract the right channel of a stereo source

Type:

(source(audio=2, video=0, midi=0)) -> source(audio=1,
video=0, midi=0)

Arguments:

(unlabeled) (of type source(audio=2, video=0, midi=0)): Source to extract from

`swap`

Swap two channels of a stereo source.

Type:

(?id : string, source(audio=2, video=0, midi=0)) ->
source(audio=2, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio=2, video=0, midi=0))

Source / Input

`blank`

Produce silence and blank images.

Type:

(?id : string, ?duration : float) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type float, which defaults to 0.0): Duration of blank tracks in seconds, default means forever.

`empty`

A source that does not produce anything. No silence, no track at all.

Type:

(?id : string) -> source(audio='a, video='b, midi='c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.

`fail`

Creates a source that fails to produce anything.

Type:

(?id : string) -> source('b)

Arguments:

id (of type string, which defaults to "")

`gstreamer.single.audio`

Play a single audio file using GStreamer.

Type:

(?id : string, ?on_error : (('a) -> float), {string}) ->
source(audio='#c+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
on_error (of type ('a) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens.
(unlabeled) (of type {string}): URI of the file to be played.

`in`

Create a source from the first available input driver in pulseaudio, portaudio, oss, alsa, blank.

Type:

(?id : string, ?start : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?fallible : bool) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "")
start (of type bool, which defaults to true)
on_start (of type () -> unit, which defaults to <fun>)
on_stop (of type () -> unit, which defaults to <fun>)
fallible (of type bool, which defaults to false)

`input.alsa`

Stream from an ALSA input device.

Type:

(?id : string, ?bufferize : bool, ?clock_safe : bool,
 ?device : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool) -> active_source(audio='#a+1, video=0,
midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
bufferize (of type bool, which defaults to true): Bufferize input
clock_safe (of type bool, which defaults to true): Force the use of the dedicated ALSA clock
device (of type string, which defaults to "default"): Alsa device to use
fallible (of type bool, which defaults to false): Allow the input to stop. When false, the source will be infallible but the stop command won’t have any effect.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when input starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when input stops.
start (of type bool, which defaults to true): Start input as soon as it is created. Disabling it is only taken into account for a fallible input.

`input.external.avi`

Stream data from an external application.

Type:

(?id : string, ?buffer : float, ?max : float,
 ?restart : bool, ?restart_on_error : bool, string) ->
source(audio='#a, video='#b, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 1.0): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
restart (of type bool, which defaults to true): Restart process when exited.
restart_on_error (of type bool, which defaults to false): Restart process when exited with error.
(unlabeled) (of type string): Command to execute.

This function is experimental.

`input.external.rawaudio`

Stream raw PCM data from an external application.

Type:

(?id : string, ?buffer : float, ?channels : int,
 ?max : float, ?restart : bool, ?restart_on_error : bool,
 ?samplerate : int, string) -> source(audio='#a+1,
video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
channels (of type int, which defaults to 2): Number of channels.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
restart (of type bool, which defaults to true): Restart process when exited.
restart_on_error (of type bool, which defaults to false): Restart process when exited with error.
samplerate (of type int, which defaults to 44100): Samplerate.
(unlabeled) (of type string): Command to execute.

`input.external.rawvideo`

Stream data from an external application.

Type:

(?id : string, ?buffer : float, ?max : float,
 ?restart : bool, ?restart_on_error : bool, string) ->
source(audio=0, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 1.0): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
restart (of type bool, which defaults to true): Restart process when exited.
restart_on_error (of type bool, which defaults to false): Restart process when exited with error.
(unlabeled) (of type string): Command to execute.

This function is experimental.

`input.external.wav`

Stream WAV data from an external application.

Type:

(?id : string, ?buffer : float, ?max : float,
 ?restart : bool, ?restart_on_error : bool, string) ->
source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
restart (of type bool, which defaults to true): Restart process when exited.
restart_on_error (of type bool, which defaults to false): Restart process when exited with error.
(unlabeled) (of type string): Command to execute.

`input.gstreamer.audio`

Stream audio from a GStreamer pipeline.

Type:

(?id : string, ?max : float,
 ?on_error : ((string) -> float), ?pipeline : {string},
 ?restart : bool) -> source(audio='#b+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
pipeline (of type {string}, which defaults to "audiotestsrc"): GStreamer pipeline to input from.
restart (of type bool, which defaults to true): Restart input on end of stream event.

`input.gstreamer.audio_video`

Stream audio+video from a GStreamer pipeline.

Type:

(?id : string, ?audio_pipeline : {string}, ?max : float,
 ?on_error : ((string) -> float), ?pipeline : {string},
 ?restart : bool, ?video_pipeline : {string}) ->
source(audio=2, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
audio_pipeline (of type {string}, which defaults to "audiotestsrc"): Audio pipeline to input from.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
pipeline (of type {string}, which defaults to ""): Main GStreamer pipeline.
restart (of type bool, which defaults to true): Restart input on end of stream event.
video_pipeline (of type {string}, which defaults to "videotestsrc"): Video pipeline to input from.

`input.gstreamer.video`

Stream video from a GStreamer pipeline.

Type:

(?id : string, ?max : float,
 ?on_error : ((string) -> float), ?pipeline : {string},
 ?restart : bool) -> source(audio=0, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
pipeline (of type {string}, which defaults to "videotestsrc"): GStreamer pipeline to input from.
restart (of type bool, which defaults to true): Restart input on end of stream event.

`input.harbor`

Create a source that receives a http/icecast stream and forwards it as a stream.

Type:

(?id : string, ?auth : ((string, string) -> bool),
 ?buffer : float, ?debug : bool, ?dumpfile : string,
 ?icy : bool, ?icy_metadata_charset : string,
 ?logfile : string, ?max : float,
 ?metadata_charset : string,
 ?on_connect : (([string * string]) -> unit),
 ?on_disconnect : (() -> unit), ?password : string,
 ?port : int, ?replay_metadata : bool, ?timeout : float,
 ?user : string, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
auth (of type (string, string) -> bool, which defaults to fun (_,_) -> false): Authentication function. f(login,password) returns true if the user should be granted access for this login. Override any other method if used.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
debug (of type bool, which defaults to false): Run in debugging mode by not catching some exceptions.
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
icy (of type bool, which defaults to false): Enable ICY (shoutcast) protocol.
icy_metadata_charset (of type string, which defaults to ""): ICY (shoutcast) metadata charset. Guessed if empty. Default for shoutcast is ISO-8859-1. Set to that value if all your clients send metadata using this charset and automatic detection is not working for you.
logfile (of type string, which defaults to ""): Log buffer status to file, for debugging purpose. Disabled if empty.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
metadata_charset (of type string, which defaults to ""): Metadata charset for non-ICY (shoutcast) source protocols. Guessed if empty.
on_connect (of type ([string * string]) -> unit, which defaults to <fun>): Function to execute when a source is connected. Its receives the list of headers, of the form: (,). All labels are lowercase.
on_disconnect (of type () -> unit, which defaults to <fun>): Functions to excecute when a source is disconnected
password (of type string, which defaults to "hackme"): Source password.
port (of type int, which defaults to 8005): Port used to connect to the source.
replay_metadata (of type bool, which defaults to false): Replay last known metadata when switching back to this source. This helps when source has dropped due to temporary connection issues.
timeout (of type float, which defaults to 30.0): Timeout for source connectionn.
user (of type string, which defaults to "source"): Source user.
(unlabeled) (of type string): Mountpoint to look for.

`input.harbor.ssl`

Retrieves the given https stream from the harbor.

Type:

(?id : string, ?auth : ((string, string) -> bool),
 ?buffer : float, ?debug : bool, ?dumpfile : string,
 ?icy : bool, ?icy_metadata_charset : string,
 ?logfile : string, ?max : float,
 ?metadata_charset : string,
 ?on_connect : (([string * string]) -> unit),
 ?on_disconnect : (() -> unit), ?password : string,
 ?port : int, ?replay_metadata : bool, ?timeout : float,
 ?user : string, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
auth (of type (string, string) -> bool, which defaults to fun (_,_) -> false): Authentication function. f(login,password) returns true if the user should be granted access for this login. Override any other method if used.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
debug (of type bool, which defaults to false): Run in debugging mode by not catching some exceptions.
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
icy (of type bool, which defaults to false): Enable ICY (shoutcast) protocol.
icy_metadata_charset (of type string, which defaults to ""): ICY (shoutcast) metadata charset. Guessed if empty. Default for shoutcast is ISO-8859-1. Set to that value if all your clients send metadata using this charset and automatic detection is not working for you.
logfile (of type string, which defaults to ""): Log buffer status to file, for debugging purpose. Disabled if empty.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
metadata_charset (of type string, which defaults to ""): Metadata charset for non-ICY (shoutcast) source protocols. Guessed if empty.
on_connect (of type ([string * string]) -> unit, which defaults to <fun>): Function to execute when a source is connected. Its receives the list of headers, of the form: (,). All labels are lowercase.
on_disconnect (of type () -> unit, which defaults to <fun>): Functions to excecute when a source is disconnected
password (of type string, which defaults to "hackme"): Source password.
port (of type int, which defaults to 8005): Port used to connect to the source.
replay_metadata (of type bool, which defaults to false): Replay last known metadata when switching back to this source. This helps when source has dropped due to temporary connection issues.
timeout (of type float, which defaults to 30.0): Timeout for source connectionn.
user (of type string, which defaults to "source"): Source user.
(unlabeled) (of type string): Mountpoint to look for.

`input.hls`

Play an HLS stream.

Type:

(?id : string, ?reload : float, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
reload (of type float, which defaults to 10.0): How often (in seconds) the playlist should be reloaded.
(unlabeled) (of type string): Playlist URI

This function is experimental.

`input.http`

Create a source that fetches a http stream.

Type:

(?id : string, ?autostart : bool, ?bind_address : string,
 ?buffer : float, ?debug : bool, ?force_mime : string,
 ?logfile : string, ?max : float,
 ?new_track_on_metadata : bool,
 ?on_connect : (([string * string]) -> unit),
 ?on_disconnect : (() -> unit), ?playlist_mode : string,
 ?poll_delay : float, ?timeout : float,
 ?user_agent : string, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
autostart (of type bool, which defaults to true): Initially start relaying or not.
bind_address (of type string, which defaults to ""): Address to bind on the local machine. This option can be useful if your machine is bound to multiple IPs. Empty means no bind address.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
debug (of type bool, which defaults to false): Run in debugging mode, not catching some exceptions.
force_mime (of type string, which defaults to ""): Force mime data type. Not used if empty.
logfile (of type string, which defaults to ""): Log buffer status to file, for debugging purpose. Disabled if empty.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
new_track_on_metadata (of type bool, which defaults to true): Treat new metadata as new track.
on_connect (of type ([string * string]) -> unit, which defaults to <fun>): Function to execute when a source is connected. Its receives the list of headers, of the form: (,). All labels are lowercase.
on_disconnect (of type () -> unit, which defaults to <fun>): Function to excecute when a source is disconnected
playlist_mode (of type string, which defaults to "normal"): Valid modes are “normal”, “random”, “randomize” and “first”. The first ones have the same meaning as for the mode parameter of the playlist operator. The last one discards all entries but the first one.
poll_delay (of type float, which defaults to 2.0): Polling delay when trying to connect to the stream.
timeout (of type float, which defaults to 30.0): Timeout for source connectionn.
user_agent (of type string, which defaults to "Liquidsoap/1.4.4 (Unix; OCaml 4.10.0)"): User agent.
(unlabeled) (of type string): URL of an http stream (default port is 80).

`input.https`

Create a source that fetches a https stream.

Type:

(?id : string, ?autostart : bool, ?bind_address : string,
 ?buffer : float, ?debug : bool, ?force_mime : string,
 ?logfile : string, ?max : float,
 ?new_track_on_metadata : bool,
 ?on_connect : (([string * string]) -> unit),
 ?on_disconnect : (() -> unit), ?playlist_mode : string,
 ?poll_delay : float, ?timeout : float,
 ?user_agent : string, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
autostart (of type bool, which defaults to true): Initially start relaying or not.
bind_address (of type string, which defaults to ""): Address to bind on the local machine. This option can be useful if your machine is bound to multiple IPs. Empty means no bind address.
buffer (of type float, which defaults to 2.0): Duration of the pre-buffered data.
debug (of type bool, which defaults to false): Run in debugging mode, not catching some exceptions.
force_mime (of type string, which defaults to ""): Force mime data type. Not used if empty.
logfile (of type string, which defaults to ""): Log buffer status to file, for debugging purpose. Disabled if empty.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
new_track_on_metadata (of type bool, which defaults to true): Treat new metadata as new track.
on_connect (of type ([string * string]) -> unit, which defaults to <fun>): Function to execute when a source is connected. Its receives the list of headers, of the form: (,). All labels are lowercase.
on_disconnect (of type () -> unit, which defaults to <fun>): Function to excecute when a source is disconnected
playlist_mode (of type string, which defaults to "normal"): Valid modes are “normal”, “random”, “randomize” and “first”. The first ones have the same meaning as for the mode parameter of the playlist operator. The last one discards all entries but the first one.
poll_delay (of type float, which defaults to 2.0): Polling delay when trying to connect to the stream.
timeout (of type float, which defaults to 30.0): Timeout for source connectionn.
user_agent (of type string, which defaults to "Liquidsoap/1.4.4 (Unix; OCaml 4.10.0)"): User agent.
(unlabeled) (of type string): URL of an https stream (default port is 443).

`input.jack`

Get stream from jack.

Type:

(?id : string, ?buffer_size : int, ?clock_safe : bool,
 ?server : string) -> source(audio='#a+1, video=0,
midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer_size (of type int, which defaults to 2): Set buffer size, in frames. Must be >= 1.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated bjack clock.
server (of type string, which defaults to ""): Jack server to connect to.

`input.mplayer`

Stream data from mplayer

Type:

(?id : string, ?restart : bool, ?restart_on_error : bool,
 ?buffer : float, ?max : float, string) ->
source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to "input.mplayer")
restart (of type bool, which defaults to true): restart on exit.
restart_on_error (of type bool, which defaults to false): restart on exit with error.
buffer (of type float, which defaults to 0.2): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
(unlabeled) (of type string): data URI.

`input.oss`

Stream from an OSS input device.

Type:

(?id : string, ?clock_safe : bool, ?device : string,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?start : bool) ->
active_source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated OSS clock.
device (of type string, which defaults to "/dev/dsp"): OSS device to use.
fallible (of type bool, which defaults to false): Allow the input to stop. When false, the source will be infallible but the stop command won’t have any effect.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when input starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when input stops.
start (of type bool, which defaults to true): Start input as soon as it is created. Disabling it is only taken into account for a fallible input.

`input.portaudio`

Stream from a portaudio input device.

Type:

(?id : string, ?buflen : int, ?clock_safe : bool,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?start : bool) ->
source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buflen (of type int, which defaults to 256): Length of a buffer in samples.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated Portaudio clock.
fallible (of type bool, which defaults to false): Allow the input to stop. When false, the source will be infallible but the stop command won’t have any effect.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when input starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when input stops.
start (of type bool, which defaults to true): Start input as soon as it is created. Disabling it is only taken into account for a fallible input.

`input.pulseaudio`

Stream from a portaudio input device.

Type:

(?id : string, ?client : string, ?clock_safe : bool,
 ?device : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool) -> active_source(audio='#a+1, video='#b,
midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
client (of type string, which defaults to "liquidsoap")
clock_safe (of type bool, which defaults to true): Force the use of the dedicated Pulseaudio clock.
device (of type string, which defaults to ""): Device to use. Uses default if set to ““.
fallible (of type bool, which defaults to false): Allow the input to stop. When false, the source will be infallible but the stop command won’t have any effect.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when input starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when input stops.
start (of type bool, which defaults to true): Start input as soon as it is created. Disabling it is only taken into account for a fallible input.

`input.srt`

Start a SRT agent in listener mode to receive and decode a stream.

Type:

(?id : string, ?bind_address : string,
 ?clock_safe : bool, ?content_type : string,
 ?max : float, ?messageapi : bool,
 ?on_connect : ((unit) -> unit),
 ?on_disconnect : (() -> unit), ?payload_size : int,
 ?port : int) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
bind_address (of type string, which defaults to "0.0.0.0"): Address to bind on the local machine.
clock_safe (of type bool, which defaults to true): Force the use of a decicated clock.
content_type (of type string, which defaults to "application/ffmpeg"): Content-Type (mime type) used to find a decoder for the input stream.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
messageapi (of type bool, which defaults to true): Use message api
on_connect (of type (unit) -> unit, which defaults to <fun>): Function to execute when a source is connected.
on_disconnect (of type () -> unit, which defaults to <fun>): Function to excecute when a stream is disconnected
payload_size (of type int, which defaults to 1316): Payload size.
port (of type int, which defaults to 8000): Port to bind on the local machine. The term port as used in SRT is occasionally identical to the term UDP port. However SRT offers more flexibility than UDP because it manages ports as its own resources. For example, one port may be shared between various services.

`input.udp`

Input encoded data from UDP, without any control whatsoever.

Type:

(?id : string, ?buffer : float, host : string,
 port : int, string) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 1.0): Duration of buffered data before starting playout.
host (of type string)
port (of type int)
(unlabeled) (of type string): Mime type.

This function is experimental.

`input.v4l2`

Stream from a video4linux 2 input device, such as a webcam.

Type:

(?id : string, ?device : string,
 ?on_error : ((string) -> float)) -> source(audio=0,
video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
device (of type string, which defaults to "/dev/video0"): V4L2 device to use.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens.

`input.v4l2_with_audio`

Stream from a video4linux 2 input device, such as a webcam.

Type:

(?id : string, ?device : string,
 ?on_error : ((string) -> float)) -> source(audio=2,
video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
device (of type string, which defaults to "/dev/video0"): V4L2 device to use.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens.

`noise`

Generate (audio and/or video) white noise.

Type:

(?id : string, ?duration : float) -> source(audio='a,
video='b, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type float, which defaults to 0.0)

`output.file.hls.gstreamer`

Play an http live stream.

Type:

(?id : string, ?on_error : ((string) -> float), {string}) ->
source(audio=2, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens.
(unlabeled) (of type {string}): URI of the HLS stream index.

`output.file.hls.gstreamer.audio`

Play an audio-only http live stream.

Type:

(?id : string, ?on_error : ((string) -> float), {string}) ->
source(audio='#b+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens.
(unlabeled) (of type {string}): URI of the HLS stream index.

`playlist`

Loop on a playlist of URIs.

Type:

(?id : string, ?check_next : ((request('a)) -> bool),
 ?conservative : bool, ?default_duration : float,
 ?length : float, ?mime_type : string, ?mode : string,
 ?on_track : ((last : bool, int) -> bool),
 ?prefix : string, ?reload : int, ?reload_mode : string,
 ?timeout : float, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
check_next (of type (request('a)) -> bool, which defaults to <fun>): Function used to filter next tracks. A candidate track is only validated if the function returns true on it. The function is called before resolution, hence metadata will only be available for requests corresponding to local files. This is typically used to avoid repetitions, but be careful: if the function rejects all attempts, the playlist will enter into a consuming loop and stop playing anything.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 40.0): How much audio (in sec.) should be queued in advance.
mime_type (of type string, which defaults to ""): Default MIME type for the playlist. Empty string means automatic detection.
mode (of type string, which defaults to "randomize"): Play the files in the playlist either in the order (“normal” mode), or shuffle the playlist each time it is loaded, and play it in this order for a whole round (“randomize” mode), or pick a random file in the playlist each time (“random” mode).
on_track (of type (last : bool, int) -> bool, which defaults to fun (_,~last=_) -> false): Function to execute when playlist is about to play its next track. Receives track position in the playlist and wether this is the last track. Force a reload by returning true in this function.
prefix (of type string, which defaults to ""): Add a constant prefix to all requests. Useful for passing extra information using annotate, or for resolution through a particular protocol, such as replaygain.
reload (of type int, which defaults to 0): Amount of time (in seconds or rounds), when applicable, before which the playlist is reloaded; 0 means never.
reload_mode (of type string, which defaults to "seconds"): Unit of the reload parameter, either ‘rounds’, ‘seconds’ or ‘watch’ (reload the file whenever it is changed).
timeout (of type float, which defaults to 20.0): Timeout (in sec.) for a single download.
(unlabeled) (of type string): URI where to find the playlist.

`playlist.once`

Custom playlist source written using the script language. It will read directory or playlist, play all files and stop.

Type:

(?id : string, ?random : bool, ?on_done : (() -> unit),
 ?reload_mode : string, ?default_duration : float,
 ?length : float, ?conservative : bool,
 ?filter : (([string * string]) -> bool), string) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
random (of type bool, which defaults to false): Randomize playlist content
on_done (of type () -> unit, which defaults to <fun>): Function to execute when the playlist is finished
reload_mode (of type string, which defaults to ""): If set to “watch”, will be reloaded when the playlist is changed
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 10.0): How much audio (in sec.) should be queued in advance.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
filter (of type ([string * string]) -> bool, which defaults to fun (_) -> true): Filter out some files depending on metadata
(unlabeled) (of type string): Playlist URI

`playlist.reloadable`

Custom playlist source written using the script language. Will read directory or playlist, play all files and stop. Returns a pair (reload,source) where reload is a function of type (?uri:string)->unit used to reload the source and source is the actual source. The reload function can optionally be called with a new playlist URI. Otherwise, it reloads the previous URI.

Type:

(?id : string, ?random : bool, ?on_done : (() -> unit),
 ?default_duration : float, ?length : float,
 ?conservative : bool,
 ?filter : (([string * string]) -> bool), string) ->
((?uri : string) -> unit) * source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
random (of type bool, which defaults to false): Randomize playlist content
on_done (of type () -> unit, which defaults to <fun>): Function to execute when the playlist is finished
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 10.0): How much audio (in sec.) should be queued in advance.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
filter (of type ([string * string]) -> bool, which defaults to fun (_) -> true): Filter out some files depending on metadata
(unlabeled) (of type string): Playlist URI

`playlist.safe`

Loop on a playlist of local files, and never fail. In order to do so, it has to check every file at the loading, so the streamer startup may take a few seconds. To avoid this, use a standard playlist, and put only a few local files in a default safe_playlist in order to ensure the liveness of the streamer.

Type:

(?id : string, ?mime_type : string, ?mode : string,
 ?on_track : ((last : bool, int) -> bool),
 ?prefix : string, ?reload : int, ?reload_mode : string,
 string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mime_type (of type string, which defaults to ""): Default MIME type for the playlist. Empty string means automatic detection.
mode (of type string, which defaults to "randomize"): Play the files in the playlist either in the order (“normal” mode), or shuffle the playlist each time it is loaded, and play it in this order for a whole round (“randomize” mode), or pick a random file in the playlist each time (“random” mode).
on_track (of type (last : bool, int) -> bool, which defaults to fun (_,~last=_) -> false): Function to execute when playlist is about to play its next track. Receives track position in the playlist and wether this is the last track. Force a reload by returning true in this function.
prefix (of type string, which defaults to ""): Add a constant prefix to all requests. Useful for passing extra information using annotate, or for resolution through a particular protocol, such as replaygain.
reload (of type int, which defaults to 0): Amount of time (in seconds or rounds), when applicable, before which the playlist is reloaded; 0 means never.
reload_mode (of type string, which defaults to "seconds"): Unit of the reload parameter, either ‘rounds’, ‘seconds’ or ‘watch’ (reload the file whenever it is changed).
(unlabeled) (of type string): URI where to find the playlist.

`request.dynamic.list`

Play request dynamically created by a given function.

Type:

(?id : string, ?conservative : bool,
 ?default_duration : float, ?length : float,
 ?retry_delay : {float}, ?timeout : float,
 (() -> [request('b)])) -> source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 40.0): How much audio (in sec.) should be queued in advance.
retry_delay (of type {float}, which defaults to 0.1): Retry after a given time (in seconds) when callback returns an empty list.
timeout (of type float, which defaults to 20.0): Timeout (in sec.) for a single download.
(unlabeled) (of type () -> [request('b)])

`request.equeue`

Receive URIs from users, and play them. Insertion and deletion possible at any position.

Type:

(?id : string, ?conservative : bool,
 ?default_duration : float, ?length : float,
 ?timeout : float) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 40.0): How much audio (in sec.) should be queued in advance.
timeout (of type float, which defaults to 20.0): Timeout (in sec.) for a single download.

`request.queue`

Receive URIs from users, and play them.

Type:

(?id : string, ?conservative : bool,
 ?default_duration : float, ?interactive : bool,
 ?length : float, ?queue : [request('a)],
 ?timeout : float) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
interactive (of type bool, which defaults to true): Should the queue be controllable via telnet?
length (of type float, which defaults to 40.0): How much audio (in sec.) should be queued in advance.
queue (of type [request('a)], which defaults to []): Initial queue of requests.
timeout (of type float, which defaults to 20.0): Timeout (in sec.) for a single download.

`saw`

Generate a saw wave.

Type:

(?id : string, ?amplitude : float, ?duration : float,
 ?float) -> source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type float, which defaults to 1.0): Maximal value of the waveform.
duration (of type float, which defaults to 0.0): Duration in seconds (0. means infinite).
(unlabeled) (of type float, which defaults to 440.0): Frequency of the saw.

`sine`

Generate a sine wave.

Type:

(?id : string, ?amplitude : float, ?duration : float,
 ?float) -> source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type float, which defaults to 1.0): Maximal value of the waveform.
duration (of type float, which defaults to 0.0): Duration in seconds (0. means infinite).
(unlabeled) (of type float, which defaults to 440.0): Frequency of the sine.

`single`

Loop on a request. It never fails if the request is static, meaning that it can be fetched once. Typically, http, ftp, say requests are static, and time is not.

Type:

(?id : string, ?conservative : bool,
 ?default_duration : float, ?length : float,
 ?timeout : float, string) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 40.0): How much audio (in sec.) should be queued in advance.
timeout (of type float, which defaults to 20.0): Timeout (in sec.) for a single download.
(unlabeled) (of type string): URI where to find the file

`square`

Generate a square wave.

Type:

(?id : string, ?amplitude : float, ?duration : float,
 ?float) -> source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type float, which defaults to 1.0): Maximal value of the waveform.
duration (of type float, which defaults to 0.0): Duration in seconds (0. means infinite).
(unlabeled) (of type float, which defaults to 440.0): Frequency of the square.

Source / Liquidsoap

`buffer`

Create a buffer between two different clocks.

Type:

(?id : string, ?buffer : float, ?fallible : bool,
 ?max : float, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?start : bool, source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 1.0): Amount of data to pre-buffer, in seconds.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
max (of type float, which defaults to 10.0): Maximum amount of buffered data, in seconds.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source('a))

`buffer.adaptative`

Create a buffer between two different clocks. The speed of the output is adapted so that no buffer underrun or overrun occurs. This wonderful behavior has a cost: the pitch of the sound might be changed a little.

Type:

(?id : string, ?averaging : float, ?buffer : float,
 ?fallible : bool, ?limit : float, ?max : float,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?reset : bool, ?start : bool, source(audio='#a+1,
 video=0, midi=0)) -> source(audio='#a+1, video=0,
midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
averaging (of type float, which defaults to 30.0): Half-life for the averaging of the buffer size, in seconds.
buffer (of type float, which defaults to 1.0): Amount of data to pre-buffer, in seconds.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
limit (of type float, which defaults to 1.25): Maximum acceleration or deceleration factor.
max (of type float, which defaults to 10.0): Maximum amount of buffered data, in seconds.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
reset (of type bool, which defaults to false): Reset speed estimation to 1. when the source becomes available again.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0))

This function is experimental.

Source / MIDI Processing

`midi.chord`

Generate a chord.

Type:

(?id : string, ?metadata : string, source(audio='#a,
 video='#b, midi='#c)) -> source(audio='#a, video='#b,
midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
metadata (of type string, which defaults to "chord"): Name of the metadata containing the chords.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`midi.merge_all`

Merge all MIDI tracks in one.

Type:

(?id : string, ?track_out : int, source(audio='#a,
 video='#b, midi='#c+1)) -> source(audio='#a, video='#b,
midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
track_out (of type int, which defaults to 0): Destination track.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c+1))

`midi.remove`

Remove MIDI tracks.

Type:

(?id : string, [int], source(audio='#a, video='#b,
 midi='#c+1)) -> source(audio='#a, video='#b, midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type [int]): Tracks to remove.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c+1))

Source / Output

`gstreamer.encode_jpeg_avi`

Encode jpeg video file using gstreamer

Type:

('a, source(audio='#b, video='#c+1, midi='#d)) ->
active_source(audio='#b, video='#c+1, midi='#d)

Arguments:

(unlabeled) (of type 'a): Encoded file name
(unlabeled) (of type source(audio='#b, video='#c+1, midi='#d)): Source

`gstreamer.encode_mp3`

Encode a mp3 file using gstreamer

Type:

('a, source(audio='#b+1, video='#c, midi='#d)) ->
active_source(audio='#b+1, video='#c, midi='#d)

Arguments:

(unlabeled) (of type 'a): Encoded file name
(unlabeled) (of type source(audio='#b+1, video='#c, midi='#d)): Source

`gstreamer.encode_x264_avi`

Encode an x264 video file using gstreamer

Type:

('a, source(audio='#b, video='#c+1, midi='#d)) ->
active_source(audio='#b, video='#c+1, midi='#d)

Arguments:

(unlabeled) (of type 'a): Encoded file name
(unlabeled) (of type source(audio='#b, video='#c+1, midi='#d)): Source

`gstreamer.rtp.mpeg4`

Broadcast a video in RTP. In order to play it, save the following in xxx.sdp and use vlc xxx.sdp:

v=0
m=video 5000 RTP/AVP 96
c=IN IP4 127.0.0.1
a=rtpmap:96 MP4V-ES/90000

Type:

(?host : string, ?port : int, source(audio='#a,
 video='#b+1, midi='#c)) -> active_source(audio='#a,
video='#b+1, midi='#c)

Arguments:

host (of type string, which defaults to "127.0.0.1")
port (of type int, which defaults to 5000)
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`out`

Output a stream using the output.prefered operator. The input source does not need to be infallible, blank will just be played during failures.

Type:

(source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c)): the source to output

`output.alsa`

Output the source’s stream to an ALSA output device.

Type:

(?id : string, ?bufferize : bool, ?clock_safe : bool,
 ?device : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool, source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
bufferize (of type bool, which defaults to true): Bufferize output
clock_safe (of type bool, which defaults to true): Force the use of the dedicated ALSA clock
device (of type string, which defaults to "default"): Alsa device to use
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.ao`

Output stream to local sound card using libao.

Type:

(?id : string, ?buffer_size : int,
 ?channels_matrix : string, ?clock_safe : bool,
 ?driver : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?options : [string * string], ?start : bool,
 source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer_size (of type int, which defaults to 2): Set buffer size, in frames.
channels_matrix (of type string, which defaults to ""): Output channels matrix, “” for AO’s default.
clock_safe (of type bool, which defaults to true): Use the dedicated AO clock.
driver (of type string, which defaults to ""): Driver to be used, “” for AO’s default.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
options (of type [string * string], which defaults to []): List of parameters, depends on the driver.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.dummy`

Dummy output for debugging purposes.

Type:

(?id : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool, source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source('a))

`output.external`

Send the stream to a process’ standard input.

Type:

(?id : string, ?fallible : bool, ?flush : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?reopen_delay : float, ?reopen_on_metadata : bool,
 ?reopen_when : (() -> bool), ?start : bool, format('a),
 {string}, source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
flush (of type bool, which defaults to false): Perform a flush after each write.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
reopen_delay (of type float, which defaults to 120.0): Prevent re-opening within that delay, in seconds.
reopen_on_metadata (of type bool, which defaults to false): Re-open on every new metadata information.
reopen_when (of type () -> bool, which defaults to {false}): When should the output be re-opened.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type {string}): Process to pipe data to. Some strftime conversion specifiers are available: %SMHdmY. You can also use $(..) interpolation notation for metadata.
(unlabeled) (of type source('a))

`output.file`

Output the source stream to a file.

Type:

(?id : string, ?append : bool, ?dir_perm : int,
 ?fallible : bool, ?flush : bool,
 ?on_close : ((string) -> unit),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?perm : int, ?reopen_delay : float,
 ?reopen_on_metadata : bool, ?reopen_when : (() -> bool),
 ?start : bool, format('a), {string}, source('a)) ->
active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
append (of type bool, which defaults to false): Do not truncate but append in the file if it exists.
dir_perm (of type int, which defaults to 511): Permission of the directories if some have to be created, up to umask. Although you can enter values in octal notation (0oXXX) they will be displayed in decimal (for instance, 0o777 = 78^2 + 78 + 7 = 511).
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
flush (of type bool, which defaults to false): Perform a flush after each write.
on_close (of type (string) -> unit, which defaults to <fun>): This function will be called for each file, after that it is finished and closed. The filename will be passed as argument.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
perm (of type int, which defaults to 438): Permission of the file if it has to be created, up to umask. You can and should write this number in octal notation: 0oXXX. The default value is however displayed in decimal (0o666 = 68^2 + 68 + 6 = 438).
reopen_delay (of type float, which defaults to 120.0): Prevent re-opening within that delay, in seconds.
reopen_on_metadata (of type bool, which defaults to false): Re-open on every new metadata information.
reopen_when (of type () -> bool, which defaults to {false}): When should the output be re-opened.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type {string}): Filename where to output the stream. Some strftime conversion specifiers are available: %SMHdmY. You can also use $(..) interpolation notation for metadata.
(unlabeled) (of type source('a))

`output.file.hls`

Output the source stream to an HTTP live stream served from a local directory.

Type:

(?id : string, ?encode_metadata : bool, ?fallible : bool,
 ?on_file_change : ((state : string, string) -> unit),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?perm : int, ?persist : bool, ?persist_at : string,
 ?playlist : string, ?segment_duration : float,
 ?segment_name : ((position : int, extname : string,
                   string) -> string),
 ?segments : int, ?segments_overhead : int,
 ?start : bool,
 ?streams_info : [string * (int * string * string)],
 string, [string * format('a)], source('a)) ->
active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
encode_metadata (of type bool, which defaults to false): Insert metadata into encoded stream. Note: Some HLS players (in particular android native HLS player) expect a single mpegts stream. Encoding metadata will break that assumption.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_file_change (of type (state : string, string) -> unit, which defaults to <fun>): Callback executed when a file changes. state is one of: "opened", "closed" or "deleted", second argument is file path. Typical use: upload files to a CDN when done writting ("close" state and remove when "deleted".
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
perm (of type int, which defaults to 420): Permission of the created files, up to umask. You can and should write this number in octal notation: 0oXXX. The default value is however displayed in decimal (0o666 = 68^2 + 48 + 4 = 412).
persist (of type bool, which defaults to false): Persist output accross restart. If enabled, generated files (segments and playlists) are kept on shutdown and the output state at the location given by persist_at and used on restart.
persist_at (of type string, which defaults to "state.config"): Location of the configuration file used to restart the output when persist=true. Relative paths are assumed to be with regard to the directory for generated file.
playlist (of type string, which defaults to "stream.m3u8"): Playlist name (m3u8 extension is recommended).
segment_duration (of type float, which defaults to 10.0): Segment duration (in seconds).
segment_name (of type (position : int, extname : string, string) -> string, which defaults to <fun>): Segment name. Default: fun (~position,~extname,stream_name) -> "#{stream_name}_#{position}.#{extname}"
segments (of type int, which defaults to 10): Number of segments per playlist.
segments_overhead (of type int, which defaults to 5): Number of segments to keep after they have been featured in the live playlist.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
streams_info (of type [string * (int * string * string)], which defaults to []): Additional information about the streams. Should be a list of the form: [(stream_name, (bandwidth, codec, extname)]. See RFC 6381 for info about codec. Stream info are required when they cannot be inferred from the encoder.
(unlabeled) (of type string): Directory for generated files.
(unlabeled) (of type [string * format('a)]): List of specifications for each stream: (name, format).
(unlabeled) (of type source('a))

`output.gstreamer.audio`

Output stream to a GStreamer pipeline.

Type:

(?id : string, ?clock_safe : bool, ?fallible : bool,
 ?on_error : ((string) -> float),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?pipeline : string, ?start : bool, source(audio='#a+1,
 video='#b, midi='#c)) -> active_source(audio='#a+1,
video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
clock_safe (of type bool, which defaults to true): Use the dedicated GStreamer clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
pipeline (of type string, which defaults to "autoaudiosink"): GStreamer pipeline for sink.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.gstreamer.audio_video`

Output stream to a GStreamer pipeline.

Type:

(?id : string, ?audio_pipeline : string,
 ?blocking : bool, ?clock_safe : bool, ?fallible : bool,
 ?on_error : ((string) -> float),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?pipeline : string, ?start : bool,
 ?video_pipeline : string, source(audio='#a+1,
 video='#b+1, midi='#c)) -> active_source(audio='#a+1,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
audio_pipeline (of type string, which defaults to "autoaudiosink"): GStreamer pipeline for audio sink.
blocking (of type bool, which defaults to true): Pushing buffers is blocking.
clock_safe (of type bool, which defaults to true): Use the dedicated GStreamer clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
pipeline (of type string, which defaults to ""): GStreamer pipeline for sink.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
video_pipeline (of type string, which defaults to "videoconvert ! autovideosink"): GStreamer pipeline for video sink.
(unlabeled) (of type source(audio='#a+1, video='#b+1, midi='#c))

`output.gstreamer.video`

Output stream to a GStreamer pipeline.

Type:

(?id : string, ?clock_safe : bool, ?fallible : bool,
 ?on_error : ((string) -> float),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?pipeline : string, ?start : bool, source(audio='#a,
 video='#b+1, midi='#c)) -> active_source(audio='#a,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
clock_safe (of type bool, which defaults to true): Use the dedicated GStreamer clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
pipeline (of type string, which defaults to "videoconvert ! autovideosink"): GStreamer pipeline for sink.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`output.harbor`

Encode and output the stream using the harbor server.

Type:

(?id : string, ?auth : ((string, string) -> bool),
 ?buffer : int, ?burst : int, ?chunk : int,
 ?dumpfile : string, ?encoding : string,
 ?fallible : bool, ?format : string,
 ?headers : [string * string], ?metaint : int,
 mount : string,
 ?on_connect : ((headers : [string * string],
                 uri : string, protocol : string, string) ->
                unit),
 ?on_disconnect : ((string) -> unit),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?password : string, ?port : int, ?start : bool,
 ?timeout : float, ?url : string, ?user : string,
 format('a), source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
auth (of type (string, string) -> bool, which defaults to fun (_,_) -> false): Authentication function. f(login,password) returns true if the user should be granted access for this login. Override any other method if used.
buffer (of type int, which defaults to 327675): Maximun buffer per-client.
burst (of type int, which defaults to 65534): Initial burst of data sent to the client.
chunk (of type int, which defaults to 1024): Send data to clients using chunks of at least this length.
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
encoding (of type string, which defaults to ""): Encoding used to send metadata. If empty, defaults to “ISO-8859-1” for non-ogg formats and “UTF-8” otherwise.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
format (of type string, which defaults to ""): Format, e.g. “audio/ogg”. When empty, the encoder is used to guess.
headers (of type [string * string], which defaults to []): Additional headers.
metaint (of type int, which defaults to 16000): Interval used to send ICY metadata
mount (of type string)
on_connect (of type (headers : [string * string], uri : string, protocol : string, string) -> unit, which defaults to <fun>): Callback executed when connection is established.
on_disconnect (of type (string) -> unit, which defaults to <fun>): Callback executed when connection stops.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
password (of type string, which defaults to "hackme")
port (of type int, which defaults to 8000)
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
timeout (of type float, which defaults to 30.0): Timeout for network operations.
url (of type string, which defaults to "")
user (of type string, which defaults to ""): User for client connection, disabled if empty.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type source('a))

`output.harbor.hls`

Output the source stream to an HTTP live stream served from the harbor HTTP server.

Type:

(?id : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?encode_metadata : bool, ?segment_duration : float,
 ?segments : int, ?segments_overhead : int,
 ?streams_info : [string * (int * string * string)],
 ?tmpdir : string,
 ?segment_name : ((position : int, extname : string,
                   string) -> string),
 ?start : bool, ?playlist : string, ?port : int,
 ?path : string,
 ?on_file_change : ((state : string, string) -> unit),
 ?headers : [string * string], ?persist : bool,
 ?persist_at : string, [string * format('a)], source('a)) ->
active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
encode_metadata (of type bool, which defaults to false): Insert metadata into encoded stream. Note: Some HLS players (in particular android native HLS player) expect a single mpegts stream. Encoding metadata will break that assumption.
segment_duration (of type float, which defaults to 10.0): Segment duration (in seconds).
segments (of type int, which defaults to 15): Number of segments per playlist.
segments_overhead (of type int, which defaults to 10): Number of segments to keep after they have been featured in the live playlist.
streams_info (of type [string * (int * string * string)], which defaults to []): Additional information about the streams. Should be a list of the form: [(stream_name, (bandwidth, codec, extname)]. See RFC 6381 for info about codec. Stream info are required when they cannot be inferred from the encoder.
tmpdir (of type string, which defaults to ""): Directory for generated files.
segment_name (of type (position : int, extname : string, string) -> string, which defaults to <fun>): Segment name. Default: fun (~position,~extname,stream_name) -> "#{stream_name}_#{position}.#{extname}"
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
playlist (of type string, which defaults to "stream.m3u8"): Playlist name (m3u8 extension is recommended).
port (of type int, which defaults to 8000): Port for incoming harbor (http) connections.
path (of type string, which defaults to "/"): Base path for hls URIs.
on_file_change (of type (state : string, string) -> unit, which defaults to <fun>): Callback executed when a file changes. state is one of: "opened", "closed" or "deleted", second argument is file path. Typical use: upload files to a CDN when done writting ("close" state and remove when "deleted".
headers (of type [string * string], which defaults to [("Access-Control-Allow-Origin", "*")]): Default response headers.
persist (of type bool, which defaults to false): Persist output accross restart. If enabled, generated files (segments and playlists) are kept on shutdown and the output state at the location given by persist_at and used on restart.
persist_at (of type string, which defaults to "state.config"): Location of the configuration file used to restart the output when persist=true. Relative paths are assumed to be with regard to the directory for generated file.
(unlabeled) (of type [string * format('a)]): List of specifications for each stream: (name, format).
(unlabeled) (of type source('a))

`output.harbor.ssl`

Encode and output the stream using the SSL harbor server.

Type:

(?id : string, ?auth : ((string, string) -> bool),
 ?buffer : int, ?burst : int, ?chunk : int,
 ?dumpfile : string, ?encoding : string,
 ?fallible : bool, ?format : string,
 ?headers : [string * string], ?metaint : int,
 mount : string,
 ?on_connect : ((headers : [string * string],
                 uri : string, protocol : string, string) ->
                unit),
 ?on_disconnect : ((string) -> unit),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?password : string, ?port : int, ?start : bool,
 ?timeout : float, ?url : string, ?user : string,
 format('a), source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
auth (of type (string, string) -> bool, which defaults to fun (_,_) -> false): Authentication function. f(login,password) returns true if the user should be granted access for this login. Override any other method if used.
buffer (of type int, which defaults to 327675): Maximun buffer per-client.
burst (of type int, which defaults to 65534): Initial burst of data sent to the client.
chunk (of type int, which defaults to 1024): Send data to clients using chunks of at least this length.
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
encoding (of type string, which defaults to ""): Encoding used to send metadata. If empty, defaults to “ISO-8859-1” for non-ogg formats and “UTF-8” otherwise.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
format (of type string, which defaults to ""): Format, e.g. “audio/ogg”. When empty, the encoder is used to guess.
headers (of type [string * string], which defaults to []): Additional headers.
metaint (of type int, which defaults to 16000): Interval used to send ICY metadata
mount (of type string)
on_connect (of type (headers : [string * string], uri : string, protocol : string, string) -> unit, which defaults to <fun>): Callback executed when connection is established.
on_disconnect (of type (string) -> unit, which defaults to <fun>): Callback executed when connection stops.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
password (of type string, which defaults to "hackme")
port (of type int, which defaults to 8000)
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
timeout (of type float, which defaults to 30.0): Timeout for network operations.
url (of type string, which defaults to "")
user (of type string, which defaults to ""): User for client connection, disabled if empty.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type source('a))

`output.icecast`

Encode and output the stream to an icecast2 or shoutcast server.

Type:

(?id : string, ?chunked : bool,
 ?connection_timeout : float, ?description : string,
 ?dumpfile : string, ?encoding : string,
 ?fallible : bool, ?format : string, ?genre : string,
 ?headers : [string * string], ?host : string,
 ?icy_id : int, ?icy_metadata : string, ?mount : string,
 ?name : string, ?on_connect : (() -> unit),
 ?on_disconnect : (() -> unit),
 ?on_error : ((string) -> float),
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?password : string, ?port : int, ?protocol : string,
 ?public : bool, ?start : bool, ?timeout : float,
 ?url : string, ?user : string, ?verb : string,
 format('a), source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
chunked (of type bool, which defaults to false): Used cunked transfer with the ‘http(s)’ protocol.
connection_timeout (of type float, which defaults to 5.0): Timeout for establishing network connections (disabled is negative).
description (of type string, which defaults to "")
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
encoding (of type string, which defaults to ""): Encoding used to send metadata and stream info (name, genre and description). If empty, defaults to “UTF-8” for “http(s)” protocol and “ISO-8859-1” for “icy” protocol.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
format (of type string, which defaults to ""): Format, e.g. “audio/ogg”. When empty, the encoder is used to guess.
genre (of type string, which defaults to "")
headers (of type [string * string], which defaults to [("User-Agent", "Liquidsoap/1.4.4 (Unix; OCaml 4.10.0)")]): Additional headers.
host (of type string, which defaults to "localhost")
icy_id (of type int, which defaults to 1): Shoutcast source ID. Only supported by Shoutcast v2.
icy_metadata (of type string, which defaults to "guess"): Send new metadata using the ICY protocol. One of: “guess”, “true”, “false”
mount (of type string, which defaults to "Use [name]"): Source mount point. Mandatory when streaming to icecast.
name (of type string, which defaults to "Use [mount]")
on_connect (of type () -> unit, which defaults to <fun>): Callback executed when connection is established.
on_disconnect (of type () -> unit, which defaults to <fun>): Callback executed when connection stops.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. The callback receives a string representation of the error that occured and returns a float. If returned value is positive, connection will be tried again after this amount of time (in seconds).
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
password (of type string, which defaults to "hackme")
port (of type int, which defaults to 8000)
protocol (of type string, which defaults to "http"): Protocol of the streaming server: ‘http’ or ‘https’ for Icecast, ‘icy’ for shoutcast.
public (of type bool, which defaults to true)
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
timeout (of type float, which defaults to 30.0): Timeout for network read and write.
url (of type string, which defaults to "")
user (of type string, which defaults to ""): User for shout source connection. Defaults to “source” for icecast connections. Useful only in special cases, like with per-mountpoint users.
verb (of type string, which defaults to "source"): Verb to use with the ‘http(s)’ protocol. One of: ‘source’, ‘put’ or ‘post’.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type source('a))

`output.jack`

Output stream to jack.

Type:

(?id : string, ?buffer_size : int, ?clock_safe : bool,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?server : string,
 ?start : bool, source(audio='#a+1, video=0, midi=0)) ->
active_source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer_size (of type int, which defaults to 2): Set buffer size, in frames.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated bjack clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
server (of type string, which defaults to ""): Jack server to connect to.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0))

`output.oss`

Output the source’s stream to an OSS output device.

Type:

(?id : string, ?clock_safe : bool, ?device : string,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?start : bool,
 source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated OSS clock.
device (of type string, which defaults to "/dev/dsp"): OSS device to use.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.portaudio`

Output the source’s stream to a portaudio output device.

Type:

(?id : string, ?buflen : int, ?clock_safe : bool,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit), ?start : bool,
 source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buflen (of type int, which defaults to 256): Length of a buffer in samples.
clock_safe (of type bool, which defaults to true): Force the use of the dedicated Portaudio clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.prefered`

Output to local audio card using the first available driver in pulseaudio, portaudio, oss, alsa, ao, dummy.

Type:

(?id : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool, source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "")
fallible (of type bool, which defaults to false)
on_start (of type () -> unit, which defaults to <fun>)
on_stop (of type () -> unit, which defaults to <fun>)
start (of type bool, which defaults to true)
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.pulseaudio`

Output the source’s stream to a portaudio output device.

Type:

(?id : string, ?client : string, ?clock_safe : bool,
 ?device : string, ?fallible : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?start : bool, source(audio='#a+1, video='#b, midi='#c)) ->
active_source(audio='#a+1, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
client (of type string, which defaults to "liquidsoap")
clock_safe (of type bool, which defaults to true): Force the use of the dedicated Pulseaudio clock.
device (of type string, which defaults to ""): Device to use. Uses default if set to ““.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

`output.shoutcast`

Output to shoutcast.

Type:

(?id : string, ?start : bool, ?host : string,
 ?port : int, ?user : string, ?password : string,
 ?genre : string, ?url : string, ?name : string,
 ?encoding : string, ?public : bool, ?icy_id : int,
 ?format : string, ?dj : (() -> string),
 ?dumpfile : string, ?icy_metadata : string,
 ?on_connect : (() -> unit),
 ?on_disconnect : (() -> unit), ?aim : string,
 ?icq : string, ?irc : string, ?icy_reset : bool,
 ?fallible : bool, ?on_start : (() -> unit),
 ?on_stop : (() -> unit),
 ?on_error : ((string) -> float), format('a), source('a)) ->
active_source('a)

Arguments:

id (of type string, which defaults to "output.shoutcast"): Output’s ID
start (of type bool, which defaults to true): Start output threads on operator initialization.
host (of type string, which defaults to "localhost")
port (of type int, which defaults to 8000)
user (of type string, which defaults to ""): User for shout source connection. Useful only in special cases, like with per-mountpoint users.
password (of type string, which defaults to "hackme")
genre (of type string, which defaults to "")
url (of type string, which defaults to "")
name (of type string, which defaults to "")
encoding (of type string, which defaults to "ISO-8859-1"): Encoding used to send metadata and stream info.
public (of type bool, which defaults to true)
icy_id (of type int, which defaults to 1): Shoutcast source ID. Only supported by Shoutcast v2.
format (of type string, which defaults to ""): Format, e.g. “audio/ogg”. When empty, the encoder is used to guess.
dj (of type () -> string, which defaults to {""}): Callback to set dj name.
dumpfile (of type string, which defaults to ""): Dump stream to file, for debugging purpose. Disabled if empty.
icy_metadata (of type string, which defaults to "guess"): Send new metadata using the ICY protocol. One of: “guess”, “true”, “false”
on_connect (of type () -> unit, which defaults to <fun>): Callback executed when connection starts.
on_disconnect (of type () -> unit, which defaults to <fun>): Callback executed when connection stops.
aim (of type string, which defaults to "")
icq (of type string, which defaults to "")
irc (of type string, which defaults to "")
icy_reset (of type bool, which defaults to true): Reset shoutcast source buffer upon connecting (necessary for NSV).
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
on_error (of type (string) -> float, which defaults to fun (_) -> 3.): Callback executed when an error happens. If returned value is positive, connection wll be tried again after this amount of time (in seconds).
(unlabeled) (of type format('a)): Encoding format. For shoutcast, should be mp3 or AAC(+).
(unlabeled) (of type source('a)): The source to output

`output.srt`

Send a SRT stream to a distant host.

Type:

(?id : string, ?clock_safe : bool, ?fallible : bool,
 ?host : string, ?messageapi : bool,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 ?payload_size : int, ?port : int, ?start : bool,
 format('a), source('a)) -> active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
clock_safe (of type bool, which defaults to true): Force the use of a decicated clock.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
host (of type string, which defaults to "localhost"): Address to connect to.
messageapi (of type bool, which defaults to true): Use message api
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
payload_size (of type int, which defaults to 1316): Payload size.
port (of type int, which defaults to 8000): Port to bind on the local machine. The term port as used in SRT is occasionally identical to the term UDP port. However SRT offers more flexibility than UDP because it manages ports as its own resources. For example, one port may be shared between various services.
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type source('a))

`output.udp`

Output encoded data to UDP, without any control whatsoever.

Type:

(?id : string, ?fallible : bool, host : string,
 ?on_start : (() -> unit), ?on_stop : (() -> unit),
 port : int, ?start : bool, format('a), source('a)) ->
active_source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
fallible (of type bool, which defaults to false): Allow the child source to fail, in which case the output will be (temporarily) stopped.
host (of type string)
on_start (of type () -> unit, which defaults to <fun>): Callback executed when outputting starts.
on_stop (of type () -> unit, which defaults to <fun>): Callback executed when outputting stops.
port (of type int)
start (of type bool, which defaults to true): Automatically start outputting whenever possible. If true, an infallible (normal) output will start outputting as soon as it is created, and a fallible output will (re)start as soon as its source becomes available for streaming.
(unlabeled) (of type format('a)): Encoding format.
(unlabeled) (of type source('a))

This function is experimental.

`output.youtube.live`

Stream live on youtube. You need the following Gstreamer plugins: flvmux, rtmpsink, x264enc and a suitable AAC encoder (see audio_encoder params).

Type:

(?id : string, ?video_bitrate : int,
 ?audio_encoder : string, ?audio_bitrate : int,
 ?url : string, key : string, source(audio='#a+1,
 video='#b+1, midi='#c)) -> active_source(audio='#a+1,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Source ID
video_bitrate (of type int, which defaults to 2000): Video bitrate
audio_encoder (of type string, which defaults to "fdkaacenc"): Audio encoder. Can be one of: “fdkaacenc”, “voaacenc”
audio_bitrate (of type int, which defaults to 128000): Audio bitrate
url (of type string, which defaults to "rtmp://a.rtmp.youtube.com/live2"): Server URL
key (of type string): Secret key
(unlabeled) (of type source(audio='#a+1, video='#b+1, midi='#c)): Source to stream

Source / Sound Processing

`add`

Mix sources, with optional normalization. Only relay metadata from the first source that is effectively summed.

Type:

(?id : string, ?normalize : bool, ?weights : [int],
 [source(audio='#a, video='#b, midi=0)]) ->
source(audio='#a, video='#b, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
normalize (of type bool, which defaults to true)
weights (of type [int], which defaults to []): Relative weight of the sources in the sum. The empty list stands for the homogeneous distribution.
(unlabeled) (of type [source(audio='#a, video='#b, midi=0)])

`amplify`

Multiply the amplitude of the signal.

Type:

(?id : string, ?override : string, {float},
 source(audio='#b, video='#c, midi='#d)) ->
source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_amplify"): Specify the name of a metadata field that, when present and well-formed, overrides the amplification factor for the current track. Well-formed values are floats in decimal notation (e.g. 0.7) which are taken as normal/linear multiplicative factors; values can be passed in decibels with the suffix dB (e.g. -8.2 dB, but the spaces do not matter). Set to empty string "" to disable.
(unlabeled) (of type {float}): Multiplicative factor.
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`bpm`

Detect the BPM.

Type:

(?id : string, ?every : float, ((float) -> unit),
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
every (of type float, which defaults to 1.0): Interval at which BPM is computed (in second).
(unlabeled) (of type (float) -> unit): Callback function.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`clip`

Clip samples, i.e. ensure that all values are between -1 and 1: values lower than -1 become -1 and values higher than 1 become 1.

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`comb`

Comb filter.

Type:

(?id : string, ?delay : float, ?feedback : {float},
 source(audio='#b, video='#c, midi='#d)) ->
source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
delay (of type float, which defaults to 0.001): Delay in seconds.
feedback (of type {float}, which defaults to -6.0): Feedback coefficient in dB.
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`compand`

Compand the signal

Type:

(?id : string, ?mu : float, source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mu (of type float, which defaults to 1.0)
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`compress`

Compress the signal.

Type:

(?id : string, ?attack : {float}, ?gain : {float},
 ?knee : {float}, ?ratio : {float}, ?release : {float},
 ?threshold : {float}, ?window : float, source(audio='#g,
 video='#h, midi='#i)) -> source(audio='#g, video='#h,
midi='#i)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type {float}, which defaults to 100.0): Attack time (ms).
gain (of type {float}, which defaults to 0.0): Additional gain (dB).
knee (of type {float}, which defaults to 1.0): Knee radius (dB).
ratio (of type {float}, which defaults to 2.0): Gain reduction ratio (n:1).
release (of type {float}, which defaults to 400.0): Release time (ms).
threshold (of type {float}, which defaults to -10.0): Threshold level (dB).
window (of type float, which defaults to 0.1): Window for computing RMS (in sec).
(unlabeled) (of type source(audio='#g, video='#h, midi='#i))

`compress.exponential`

Exponential compressor.

Type:

(?id : string, ?mu : float, source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mu (of type float, which defaults to 2.0): Exponential compression factor, typically greater than 1.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`cross`

Cross operator, allowing the composition of the N last seconds of a track with the beginning of the next track, using a transition function depending on the relative power of the signal before and after the end of track.

Type:

(?id : string, ?active : bool, ?conservative : bool,
 ?duration : float, ?minimum : float,
 ?override_duration : string, ?width : float,
 ((float, float, [string * string], [string * string],
   source(audio='#a+1, video=0, midi=0),
   source(audio='#a+1, video=0, midi=0)) ->
  source(audio='#a+1, video=0, midi=0)),
 source(audio='#a+1, video=0, midi=0)) ->
source(audio='#a+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
active (of type bool, which defaults to false): The active behavior is to keep ticking the child’s clock when the operator is not streaming. Otherwise the child’s clock is strictly based on what is streamed off the child source, which results in time-dependent active sources to be frozen when that source is stopped.
conservative (of type bool, which defaults to true): Do not trust remaining time estimations, always buffering data in advance. This avoids being tricked by skips, either manual or caused by skip_blank().
duration (of type float, which defaults to 5.0): Duration (in seconds) of buffered data from each track that is used to compute the transision between tracks.
minimum (of type float, which defaults to -1.0): Minimum duration (in sec.) for a cross: If the track ends without any warning (e.g. in case of skip) there may not be enough data for a decent composition. Set to 0. to avoid having transitions after skips, or more to avoid transitions on short tracks. With a negative default, transitions always occur.
override_duration (of type string, which defaults to "liq_cross_duration"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
width (of type float, which defaults to 2.0): Width of the power computation window.
(unlabeled) (of type (float, float, [string * string], [string * string], source(audio='#a+1, video=0, midi=0), source(audio='#a+1, video=0, midi=0)) -> source(audio='#a+1, video=0, midi=0)): Transition function, composing from the end of a track and the next track. It also takes the power of the signal before and after the transition, and the metadata.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0))

`echo`

Add echo.

Type:

(?id : string, ?delay : {float}, ?feedback : {float},
 ?ping_pong : bool, source(audio='#c, video='#d,
 midi='#e)) -> source(audio='#c, video='#d, midi='#e)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
delay (of type {float}, which defaults to 0.5): Delay in seconds.
feedback (of type {float}, which defaults to -6.0): Feedback coefficient in dB (negative).
ping_pong (of type bool, which defaults to false): Use ping-pong delay.
(unlabeled) (of type source(audio='#c, video='#d, midi='#e))

`fade.final`

Fade a stream to silence.

Type:

(?id : string, ?duration : float, ?type : string,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "fade.final"): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading.
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`fade.in`

Fade the beginning of tracks.

Type:

(?id : string, ?duration : float,
 ?override_duration : string, ?override_type : string,
 ?type : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "fade.in"): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override.
override_duration (of type string, which defaults to "liq_fade_in"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
override_type (of type string, which defaults to "liq_fade_type"): Metadata field which, if present and correct, overrides the ‘type’ parameter for current track.
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`fade.initial`

Fade the beginning of a stream.

Type:

(?id : string, ?duration : float, ?type : string,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "fade.initial"): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading.
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`fade.out`

Fade the end of tracks.

Type:

(?id : string, ?duration : float,
 ?override_duration : string, ?override_type : string,
 ?type : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "fade.out"): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override.
override_duration (of type string, which defaults to "liq_fade_out"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
override_type (of type string, which defaults to "liq_fade_type"): Metadata field which, if present and correct, overrides the ‘type’ parameter for current track.
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`fade.skip`

Fade when the metadata trigger is received and then skip.

Type:

(?id : string, ?duration : float,
 ?override_duration : string, ?override_type : string,
 ?override_skip : string, ?type : string,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to "fade.skip"): Force the value of the source ID.
duration (of type float, which defaults to 5.0): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override.
override_duration (of type string, which defaults to "liq_fade_skip"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
override_type (of type string, which defaults to "liq_fade_skip"): Metadata field which, if present and correct, overrides the ‘type’ parameter for current track.
override_skip (of type string, which defaults to "liq_skip_meta")
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter`

Perform several kinds of filtering on the signal

Type:

(?id : string, freq : {float}, mode : string,
 ?q : {float}, ?wetness : {float}, source(audio='#d,
 video='#e, midi='#f)) -> source(audio='#d, video='#e,
midi='#f)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
freq (of type {float})
mode (of type string): Available modes are ‘low’ (for low-pass filter), ‘high’ (for high-pass filter), ‘band’ (for band-pass filter) and ‘notch’ (for notch / band-stop / band-rejection filter).
q (of type {float}, which defaults to 1.0)
wetness (of type {float}, which defaults to 1.0): How much of the original signal should be added (1. means only filtered and 0. means only original signal).
(unlabeled) (of type source(audio='#d, video='#e, midi='#f))

`filter.fir`

Low-pass FIR filter.

Type:

(?id : string, beta : float, ?coeffs : int,
 frequency : float, source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
beta (of type float): Beta should range between 0 and 1.
coeffs (of type int, which defaults to 255): Number of coefficients
frequency (of type float): Corner frequency in Hz (frequency at which the response is 0.5, that is -6 dB).
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.butterworth.bandpass`

IIR filter

Type:

(?id : string, frequency1 : float, frequency2 : float,
 ?order : int, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency1 (of type float): First corner frequency
frequency2 (of type float): Second corner frequency
order (of type int, which defaults to 4): Filter order
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.butterworth.bandstop`

IIR filter

Type:

(?id : string, frequency1 : float, frequency2 : float,
 ?order : int, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency1 (of type float): First corner frequency
frequency2 (of type float): Second corner frequency
order (of type int, which defaults to 4): Filter order
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.butterworth.high`

IIR filter

Type:

(?id : string, frequency : float, ?order : int,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
order (of type int, which defaults to 4): Filter order
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.butterworth.low`

IIR filter

Type:

(?id : string, frequency : float, ?order : int,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
order (of type int, which defaults to 4): Filter order
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.allpass`

All pass biquad filter.

Type:

(?id : string, ?bandwidth : float, frequency : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
bandwidth (of type float, which defaults to 0.333333333333): Bandwidth (in octaves)
frequency (of type float): Center frequency
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.bandpass`

Band pass biquad filter.

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Center frequency
q (of type float, which defaults to 1.0): Q
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.high`

High pass biquad filter.

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
q (of type float, which defaults to 1.0): Q
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.highshelf`

High shelf biquad filter.

Type:

(?id : string, frequency : float, ?slope : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Center frequency
slope (of type float, which defaults to 1.0): Shelf slope (in dB/octave)
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.low`

Low pass biquad filter.

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
q (of type float, which defaults to 1.0): Q
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.lowshelf`

Low shelf biquad filter.

Type:

(?id : string, frequency : float, ?slope : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
slope (of type float, which defaults to 1.0): Shelf slope (dB/octave)
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.notch`

Band pass biquad filter.

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Center frequency
q (of type float, which defaults to 1.0): Q
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.eq.peak`

Peak EQ biquad filter.

Type:

(?id : string, frequency : float, ?gain : float,
 ?q : float, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Center frequency
gain (of type float, which defaults to 1.0): Gain (in dB)
q (of type float, which defaults to 1.0): Q
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.resonator.allpass`

IIR filter

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
q (of type float, which defaults to 60.0): Quality factor
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.resonator.bandpass`

IIR filter

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
q (of type float, which defaults to 60.0): Quality factor
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.iir.resonator.bandstop`

IIR filter

Type:

(?id : string, frequency : float, ?q : float,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type float): Corner frequency
q (of type float, which defaults to 60.0): Quality factor
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`filter.rc`

First-order filter (RC filter).

Type:

(?id : string, mode : string, rc : {float},
 ?wetness : {float}, source(audio='#c, video='#d,
 midi='#e)) -> source(audio='#c, video='#d, midi='#e)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
mode (of type string): Available modes are ‘low’ (for low-pass filter), ‘high’ (for high-pass filter).
rc (of type {float}): Time constant (in seconds).
wetness (of type {float}, which defaults to 1.0): How much of the original signal should be added (1. means only filtered and 0. means only original signal).
(unlabeled) (of type source(audio='#c, video='#d, midi='#e))

`flanger`

Flanger effect.

Type:

(?id : string, ?delay : float, ?feedback : {float},
 ?freq : {float}, ?phase : {float}, source(audio='#d,
 video='#e, midi='#f)) -> source(audio='#d, video='#e,
midi='#f)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
delay (of type float, which defaults to 0.001): Delay in seconds.
feedback (of type {float}, which defaults to 0.0): Feedback coefficient in dB.
freq (of type {float}, which defaults to 0.5): Frequency in Hz.
phase (of type {float}, which defaults to 1.0): Phase difference between channels in radians.
(unlabeled) (of type source(audio='#d, video='#e, midi='#f))

`helium`

Increases the pitch, making voices sound like on helium.

Type:

(source(audio='#a+1, video=0, midi=0)) ->
source(audio='#a+1, video=0, midi=0)

Arguments:

(unlabeled) (of type source(audio='#a+1, video=0, midi=0)): The input source.

`ladspa.amp_mono`

Mono Amplifier by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?gain : {float}, source(audio='#b,
 video='#c, midi='#d)) -> source(audio='#b, video='#c,
midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
gain (of type {float}, which defaults to 1.0): Gain (0 <= gain).
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`ladspa.amp_stereo`

Stereo Amplifier by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?gain : {float}, source(audio=2, video=0,
 midi=0)) -> source(audio=2, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
gain (of type {float}, which defaults to 1.0): Gain (0 <= gain).
(unlabeled) (of type source(audio=2, video=0, midi=0))

`ladspa.delay_5s`

Simple Delay Line by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?delay : {float},
 ?dry_wet_balance : {float}, source(audio='#c, video='#d,
 midi='#e)) -> source(audio='#c, video='#d, midi='#e)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
delay (of type {float}, which defaults to 1.0): Delay (Seconds) (0 <= delay <= 5).
dry_wet_balance (of type {float}, which defaults to 0.5): Dry/Wet Balance (0 <= dry_wet_balance <= 1).
(unlabeled) (of type source(audio='#c, video='#d, midi='#e))

`ladspa.hpf`

Simple High Pass Filter by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?cutoff_frequency : {float},
 source(audio='#b, video='#c, midi='#d)) ->
source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
cutoff_frequency (of type {float}, which defaults to 440.0): Cutoff Frequency (Hz) (0 <= cutoff_frequency <= 22050).
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`ladspa.lpf`

Simple Low Pass Filter by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?cutoff_frequency : {float},
 source(audio='#b, video='#c, midi='#d)) ->
source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
cutoff_frequency (of type {float}, which defaults to 440.0): Cutoff Frequency (Hz) (0 <= cutoff_frequency <= 22050).
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`ladspa.noise_white`

White Noise Source by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?amplitude : {float}) -> source(audio=1,
video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type {float}, which defaults to 1.0): Amplitude (0 <= amplitude).

`ladspa.sine_faaa`

Sine Oscillator (Freq:audio, Amp:audio) by Richard Furse (LADSPA example plugins).

Type:

(?id : string, source(audio=2, video=0, midi=0)) ->
source(audio=1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio=2, video=0, midi=0))

`ladspa.sine_faac`

Sine Oscillator (Freq:audio, Amp:control) by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?amplitude : {float}, source(audio='#b,
 video='#c, midi='#d)) -> source(audio='#b, video='#c,
midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type {float}, which defaults to 1.0): Amplitude (0 <= amplitude).
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`ladspa.sine_fcaa`

Sine Oscillator (Freq:control, Amp:audio) by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?frequency : {float}, source(audio='#b,
 video='#c, midi='#d)) -> source(audio='#b, video='#c,
midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
frequency (of type {float}, which defaults to 440.0): Frequency (Hz) (0 <= frequency <= 22050).
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`ladspa.sine_fcac`

Sine Oscillator (Freq:control, Amp:control) by Richard Furse (LADSPA example plugins).

Type:

(?id : string, ?amplitude : {float},
 ?frequency : {float}) -> source(audio=1, video=0,
midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
amplitude (of type {float}, which defaults to 1.0): Amplitude (0 <= amplitude).
frequency (of type {float}, which defaults to 440.0): Frequency (Hz) (0 <= frequency <= 22050).

`limit`

Limit the signal.

Type:

(?id : string, ?attack : {float}, ?gain : {float},
 ?knee : {float}, ?ratio : {float}, ?release : {float},
 ?threshold : {float}, ?window : float, source(audio='#g,
 video='#h, midi='#i)) -> source(audio='#g, video='#h,
midi='#i)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type {float}, which defaults to 100.0): Attack time (ms).
gain (of type {float}, which defaults to 0.0): Additional gain (dB).
knee (of type {float}, which defaults to 1.0): Knee radius (dB).
ratio (of type {float}, which defaults to 20.0): Gain reduction ratio (n:1).
release (of type {float}, which defaults to 400.0): Release time (ms).
threshold (of type {float}, which defaults to -10.0): Threshold level (dB).
window (of type float, which defaults to 0.1): Window for computing RMS (in sec).
(unlabeled) (of type source(audio='#g, video='#h, midi='#i))

`mic_filter`

Remove low frequencies often produced by microphones.

Type:

(source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

(unlabeled) (of type source(audio='#a, video='#b, midi='#c)): The input source.

`mix`

Mixing table controllable via the telnet interface.

Type:

(?id : string, [source(audio='#a, video='#b, midi='#c)]) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type [source(audio='#a, video='#b, midi='#c)])

`normalize`

Normalize the signal. Dynamic normalization of the signal is sometimes the only option, and can make a listening experience much nicer. However, its dynamic aspect implies some limitations which can go as far as creating saturation in some extreme cases. If possible, consider using some track-based normalization techniques such as those based on replay gain. See the documentation for more details.

Type:

(?id : string, ?gain_max : {float}, ?gain_min : {float},
 ?k_down : {float}, ?k_up : {float}, ?target : {float},
 ?threshold : {float}, ?window : float, source(audio='#g,
 video='#h, midi='#i)) -> source(audio='#g, video='#h,
midi='#i)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
gain_max (of type {float}, which defaults to 6.0): Maximal gain value (dB).
gain_min (of type {float}, which defaults to -6.0): Minimal gain value (dB).
k_down (of type {float}, which defaults to 0.1): Coefficient when the power must go down (between 0 and 1, slowest to fastest).
k_up (of type {float}, which defaults to 0.005): Coefficient when the power must go up (between 0 and 1, slowest to fastest).
target (of type {float}, which defaults to -13.0): Desired RMS (dB).
threshold (of type {float}, which defaults to -40.0): Minimal RMS for activaing gain control (dB).
window (of type float, which defaults to 0.1): Duration of the window used to compute the current RMS power (second).
(unlabeled) (of type source(audio='#g, video='#h, midi='#i))

`nrj`

Compress and normalize, producing a more uniform and “full” sound.

Type:

(source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

(unlabeled) (of type source(audio='#a, video='#b, midi='#c)): The input source.

`pipe`

Process audio signal through a given process stdin/stdout.

Type:

(?id : string, ?buffer : float, ?data_length : int,
 ?max : float, process : string, ?replay_delay : float,
 ?restart : bool, ?restart_on_error : bool,
 source(audio='#a+1, video=0, midi=0)) ->
source(audio='#b+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
buffer (of type float, which defaults to 1.0): Duration of the pre-buffered data.
data_length (of type int, which defaults to -1): Length passed in the WAV data chunk. Data is streamed so no the consuming program should process it as it comes. Some program operate better when this value is set to 0, some other when it is set to the maximum length allowed by the WAV specs. Use any negative value to set to maximum length.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
process (of type string): Process used to pipe data to.
replay_delay (of type float, which defaults to -1.0): Replay track marks and metadata from the input source on the output after a given delay. If negative (default) close and flush the process on each track and metadata to get an exact timing.
restart (of type bool, which defaults to true): Restart process when exited.
restart_on_error (of type bool, which defaults to true): Restart process when exited with error.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0))

`sky`

Multiband-compression.

Type:

(source(audio='#a, video='#b, midi=0)) ->
source(audio='#a, video='#b, midi=0)

Arguments:

(unlabeled) (of type source(audio='#a, video='#b, midi=0)): The input source.

`soundtouch`

Change the rate, the tempo or the pitch of the sound.

Type:

(?id : string, ?pitch : {float}, ?rate : {float},
 ?tempo : {float}, source(audio='#d+1, video=0, midi=0)) ->
source(audio='#d+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
pitch (of type {float}, which defaults to 1.0)
rate (of type {float}, which defaults to 1.0)
tempo (of type {float}, which defaults to 1.0)
(unlabeled) (of type source(audio='#d+1, video=0, midi=0))

This function is experimental.

`stereo.ms.decode`

Decode mid+side stereo (M/S) to left+right stereo.

Type:

(?id : string, ?width : float, source(audio=2, video=0,
 midi=0)) -> source(audio=2, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
width (of type float, which defaults to 1.0): Width of the stereo field.
(unlabeled) (of type source(audio=2, video=0, midi=0))

`stereo.ms.encode`

Encode left+right stereo to mid+side stereo (M/S).

Type:

(?id : string, source(audio=2, video=0, midi=0)) ->
source(audio=2, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio=2, video=0, midi=0))

`stereo.pan`

Pan a stereo sound.

Type:

(?id : string, ?field : {float}, ?pan : {float},
 source(audio=2, video=0, midi=0)) -> source(audio=2,
video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
field (of type {float}, which defaults to 90.0): Field width in degrees (between 0 and 90).
pan (of type {float}, which defaults to 0.0): Pan ranges between -1 and 1.
(unlabeled) (of type source(audio=2, video=0, midi=0))

`stretch`

Slow down or accelerate an audio stream by stretching (sounds lower) or squeezing it (sounds higher).

Type:

(?id : string, ?active : bool, ratio : {float},
 source(audio='#b+1, video=0, midi=0)) ->
source(audio='#c+1, video=0, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
active (of type bool, which defaults to true): The active behavior is to keep ticking the child’s clock when the operator is not streaming. Otherwise the child’s clock is strictly based on what is streamed off the child source, which results in time-dependent active sources to be frozen when that source is stopped.
ratio (of type {float}): A value higher than 1 means slowing down.
(unlabeled) (of type source(audio='#b+1, video=0, midi=0))

Source / Sound Synthesis

`dssi.register`

Resgister a DSSI plugin.

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string): Path of the DSSI plugin file.

`synth.all.saw`

Saw synthesizer. It creates one synthesizer for each channel.

Type:

(?id : string, ?attack : float, ?decay : float,
 ?envelope : bool, ?release : float, ?sustain : float,
 source(audio='#a+1, video='#b, midi='#c+16)) ->
source(audio='#a+1, video='#b, midi='#c+16)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.01): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+16))

`synth.all.sine`

Sine synthesizer. It creates one synthesizer for each channel.

Type:

(?id : string, ?attack : float, ?decay : float,
 ?envelope : bool, ?release : float, ?sustain : float,
 source(audio='#a+1, video='#b, midi='#c+16)) ->
source(audio='#a+1, video='#b, midi='#c+16)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.01): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+16))

`synth.all.square`

Square synthesizer. It creates one synthesizer for each channel.

Type:

(?id : string, ?attack : float, ?decay : float,
 ?envelope : bool, ?release : float, ?sustain : float,
 source(audio='#a+1, video='#b, midi='#c+16)) ->
source(audio='#a+1, video='#b, midi='#c+16)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.01): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+16))

`synth.saw`

Saw synthesizer.

Type:

(?id : string, ?attack : float, ?channel : int,
 ?decay : float, ?envelope : bool, ?release : float,
 ?sustain : float, ?volume : float, source(audio='#a+1,
 video='#b, midi='#c+1)) -> source(audio='#a+1,
video='#b, midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
channel (of type int, which defaults to 0): MIDI channel to handle.
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.05): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
volume (of type float, which defaults to 0.3): Initial volume.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+1))

`synth.sine`

Sine synthesizer.

Type:

(?id : string, ?attack : float, ?channel : int,
 ?decay : float, ?envelope : bool, ?release : float,
 ?sustain : float, ?volume : float, source(audio='#a+1,
 video='#b, midi='#c+1)) -> source(audio='#a+1,
video='#b, midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
channel (of type int, which defaults to 0): MIDI channel to handle.
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.05): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
volume (of type float, which defaults to 0.3): Initial volume.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+1))

`synth.square`

Square synthesizer.

Type:

(?id : string, ?attack : float, ?channel : int,
 ?decay : float, ?envelope : bool, ?release : float,
 ?sustain : float, ?volume : float, source(audio='#a+1,
 video='#b, midi='#c+1)) -> source(audio='#a+1,
video='#b, midi='#c+1)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
attack (of type float, which defaults to 0.02): Envelope attack (in seconds).
channel (of type int, which defaults to 0): MIDI channel to handle.
decay (of type float, which defaults to 0.01): Envelope decay (in seconds).
envelope (of type bool, which defaults to true): Use envelope.
release (of type float, which defaults to 0.05): Envelope release (in seconds).
sustain (of type float, which defaults to 0.9): Envelope sustain level.
volume (of type float, which defaults to 0.3): Initial volume.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c+1))

Source / Track Processing

`append`

Append an extra track to every track. Set the metadata ‘liq_append’ to ‘false’ to inhibit appending on one track.

Type:

(?id : string, ?insert_missing : bool, ?merge : bool,
 source('a), (([string * string]) -> source('a))) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
insert_missing (of type bool, which defaults to true): Treat track beginnings without metadata as having empty one.
merge (of type bool, which defaults to false): Merge the track with its appended track.
(unlabeled) (of type source('a))
(unlabeled) (of type ([string * string]) -> source('a)): Given the metadata, build the source producing the track to append. This source is allowed to fail (produce nothing) if no relevant track is to be appended.

`at`

Restrict a source to play only when a predicate is true.

Type:

((() -> bool), source('a)) -> source('a)

Arguments:

(unlabeled) (of type () -> bool): The predicate, typically a time interval such as {10h-10h30}.
(unlabeled) (of type source('a))

`chop`

Regularly insert track boundaries in a stream (useful for testing tracks).

Type:

(?duration : float, ?metadata : [string * string],
 source('a)) -> source('a)

Arguments:

duration (of type float, which defaults to 3.0): Duration of a track (in seconds).
metadata (of type [string * string], which defaults to []): Metadata for tracks.
(unlabeled) (of type source('a)): The stream.

`crossfade`

Crossfade between tracks, taking the respective volume levels into account in the choice of the transition.

Type:

(?duration : float, ?override_duration : string,
 ?fade_in : float, ?fade_out : float, ?smart : bool,
 ?default : ((source(audio='#a+1, video=0, midi=0),
              source(audio='#a+1, video=0, midi=0)) ->
             source(audio='#a+1, video=0, midi=0)),
 ?high : float, ?medium : float, ?margin : float,
 ?minimum : float, ?width : float, ?conservative : bool,
 source(audio='#a+1, video=0, midi=0)) ->
source(audio='#a+1, video=0, midi=0)

Arguments:

duration (of type float, which defaults to 5.0): Duration (in seconds) of buffered data from each track that is used to compute the transision between tracks.
override_duration (of type string, which defaults to "liq_cross_duration"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
fade_in (of type float, which defaults to 3.0): Fade-in duration, if any.
fade_out (of type float, which defaults to 3.0): Fade-out duration, if any.
smart (of type bool, which defaults to false): Enable smart crossfading
default (of type (source(audio='#a+1, video=0, midi=0), source(audio='#a+1, video=0, midi=0)) -> source(audio='#a+1, video=0, midi=0), which defaults to <fun>): Smart crossfade: transition used when no rule applies (default: sequence).
high (of type float, which defaults to -15.0): Smart crossfade: value, in dB, for loud sound level.
medium (of type float, which defaults to -32.0): Smart crossfade: value, in dB, for medium sound level.
margin (of type float, which defaults to 4.0): Smart crossfade: margin to detect sources that have too different sound level for crossing.
minimum (of type float, which defaults to -1.0): Minimum duration (in sec.) for a cross: If the track ends without any warning (e.g. in case of skip) there may not be enough data for a decent composition. Set to 0. to avoid having transitions after skips, or more to avoid transitions on short tracks. With a negative default, transitions always occur.
width (of type float, which defaults to 2.0): Width of the volume analysis window.
conservative (of type bool, which defaults to true): Always prepare for a premature end-of-track.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0)): The input source.

`cue_cut`

Start track after a cue in point and stop it at cue out point. The cue points are given as metadata, in seconds from the begining of tracks.

Type:

(?id : string, ?cue_in_metadata : string,
 ?cue_out_metadata : string, ?on_cue_in : (() -> unit),
 ?on_cue_out : (() -> unit), source(audio='#a, video='#b,
 midi='#c)) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
cue_in_metadata (of type string, which defaults to "liq_cue_in"): Metadata for cue in points.
cue_out_metadata (of type string, which defaults to "liq_cue_out"): Metadata for cue out points.
on_cue_in (of type () -> unit, which defaults to <fun>): Callback to execute on cue in
on_cue_out (of type () -> unit, which defaults to <fun>): Callback to execute on cue out
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`delay`

Prevents the child from being ready again too fast after a end of track

Type:

(?id : string, ?initial : bool, float, source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
initial (of type bool, which defaults to false): Start in unavailable state, as if a track had just finished.
(unlabeled) (of type float): The source won’t be ready less than this amount of seconds after any end of track
(unlabeled) (of type source('a))

`drop_metadata`

Removes all metadata coming from a source.

Type:

(source('a)) -> source('a)

Arguments:

(unlabeled) (of type source('a))

`eat_blank`

Eat blanks, i.e., drop the contents of the stream until it is not blank anymore.

Type:

(?id : string, ?at_beginning : bool, ?max_blank : float,
 ?min_noise : float, ?start_blank : bool,
 ?threshold : float, ?track_sensitive : bool,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
at_beginning (of type bool, which defaults to false): Only eat at the beginning of a track.
max_blank (of type float, which defaults to 20.0): Maximum duration of silence allowed, in seconds.
min_noise (of type float, which defaults to 0.0): Minimum duration of noise required to end silence, in seconds.
start_blank (of type bool, which defaults to false): Start assuming we have blank.
threshold (of type float, which defaults to -40.0): Power in decibels under which the stream is considered silent.
track_sensitive (of type bool, which defaults to true): Reset blank counter at each track.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`fallback`

At the beginning of each track, select the first ready child.

Type:

(?id : string, ?override : string,
 ?replay_metadata : bool, ?track_sensitive : {bool},
 ?transition_length : float,
 ?transitions : [(source('b), source('b)) -> source('b)],
 [source('b)]) -> source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_transition_length"): Metadata field which, if present and containing a float, overrides the transition_length parameter.
replay_metadata (of type bool, which defaults to true): Replay the last metadata of a child when switching to it in the middle of a track.
track_sensitive (of type {bool}, which defaults to true): Re-select only on end of tracks.
transition_length (of type float, which defaults to 5.0): Maximun transition duration.
transitions (of type [(source('b), source('b)) -> source('b)], which defaults to []): Transition functions, padded with fun (x,y) -> y functions.
(unlabeled) (of type [source('b)]): Select the first ready source in this list.

`fallback.skip`

Special track insensitive fallback that always skips current song before switching.

Type:

(input : source('a), source('a)) -> source('a)

Arguments:

input (of type source('a)): The input source
(unlabeled) (of type source('a)): The fallback source

`insert_metadata`

Dynamically insert metadata in a stream. Returns a pair (f,s) where s is a new source and f is a function of type (?new_track,metadata)->unit, used to insert metadata in s. f also inserts a new track with the given metadata if passed new_track=true.

Type:

(?id : string, source('a)) ->
((?new_track : bool, [string * string]) -> unit) *
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source('a))

`map_first_track`

Apply a function to the first track of a source

Type:

(?id : string, ((source('a)) -> source('a)), source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type (source('a)) -> source('a)): The applied function.
(unlabeled) (of type source('a)): The input source.

`map_metadata`

Rewrite metadata on the fly using a function.

Type:

(?id : string, ?insert_missing : bool, ?strip : bool,
 ?update : bool,
 (([string * string]) -> [string * string]), source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
insert_missing (of type bool, which defaults to true): Treat track beginnings without metadata as having empty ones. The operational order is: create empty if needed, map and strip if enabled.
strip (of type bool, which defaults to false): Completely remove empty metadata. Operates on both empty values and empty metadata chunk.
update (of type bool, which defaults to true): Update metadata. If false, existing metadata are cleared and only returned values are set as new metadata.
(unlabeled) (of type ([string * string]) -> [string * string]): A function that returns new metadata.
(unlabeled) (of type source('a))

`max_duration`

Limit source duration

Type:

(?id : string, ?override : string, float, source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_remaining"): Metadata field which, if present and containing a float, overrides the remaining play time.
(unlabeled) (of type float): Maximum duration
(unlabeled) (of type source('a))

`merge_tracks`

Merge consecutive tracks from the input source. They will be considered as one big track, so on_track() will not trigger for example.

Type:

(?id : string, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source('a))

`mkavailable`

Make a source available or not depending on a boolean.

Type:

(?id : string, ?track_sensitive : bool, ?active : bool,
 ?available : bool, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to "mkavailable"): The source ID
track_sensitive (of type bool, which defaults to true): Re-select only on end of tracks.
active (of type bool, which defaults to false): Whether the source should be pulled when not available
available (of type bool, which defaults to true): Whether the source is available (true) or not (false).
(unlabeled) (of type source('a)): The stream.

`mksafe`

Turn a source into an infaillible source by adding blank when the source is not available.

Type:

(?id : string, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to "mksafe")
(unlabeled) (of type source('a)): the source to turn infaillible

`notify_metadata`

Use notify to display metadata info.

Type:

(?urgency : string, ?icon : string, ?time : int,
 ?display : (([string * string]) -> string),
 ?title : string, source('a)) -> source('a)

Arguments:

urgency (of type string, which defaults to "low"): Urgency (low|normal|critical).
icon (of type string, which defaults to "stock_smiley-22"): Icon filename or stock icon to display.
time (of type int, which defaults to 3000): Timeout in milliseconds.
display (of type ([string * string]) -> string, which defaults to <fun>): Function used to display a metadata packet.
title (of type string, which defaults to "Liquidsoap: new track"): Title of the notification message.
(unlabeled) (of type source('a))

`on_blank`

Calls a given handler when detecting a blank.

Type:

(?id : string, ?max_blank : float, ?min_noise : float,
 ?on_noise : (() -> unit), ?start_blank : bool,
 ?threshold : float, ?track_sensitive : bool,
 (() -> unit), source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
max_blank (of type float, which defaults to 20.0): Maximum duration of silence allowed, in seconds.
min_noise (of type float, which defaults to 0.0): Minimum duration of noise required to end silence, in seconds.
on_noise (of type () -> unit, which defaults to <fun>): Handler called when noise is detected.
start_blank (of type bool, which defaults to false): Start assuming we have blank.
threshold (of type float, which defaults to -40.0): Power in decibels under which the stream is considered silent.
track_sensitive (of type bool, which defaults to true): Reset blank counter at each track.
(unlabeled) (of type () -> unit): Handler called when blank is detected.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`on_end`

Call a given handler when there is less than a given amount of time remaining before then end of track.

Type:

(?id : string, ?delay : {float},
 ((float, [string * string]) -> unit), source('b)) ->
source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
delay (of type {float}, which defaults to 5.0): Execute handler when remaining time is less or equal to this value.
(unlabeled) (of type (float, [string * string]) -> unit): Function to execute. First argument is the remaining time, second is the latest metadata. That function should be fast because it is executed in the main streaming thread.
(unlabeled) (of type source('b))

`on_metadata`

Call a given handler on metadata packets.

Type:

(?id : string, (([string * string]) -> unit), source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type ([string * string]) -> unit): Function called on every metadata packet in the stream. It should be fast because it is executed in the main streaming thread.
(unlabeled) (of type source('a))

`on_offset`

Call a given handler when position in track is equal or more than a given amount of time.

Type:

(?id : string, ?force : bool, ?offset : float,
 ?override : string,
 ((float, [string * string]) -> unit), source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
force (of type bool, which defaults to false): Force execution of callback if track ends before ‘offset’ position has been reached.
offset (of type float, which defaults to -1.0): Execute handler when position in track is equal or more than to this value.
override (of type string, which defaults to "liq_on_offset"): Metadata field which, if present and containing a float, overrides the ‘offset’ parameter.
(unlabeled) (of type (float, [string * string]) -> unit): Function to execute. First argument is the actual position within the current track, second is the latest metadata. That function should be fast because it is executed in the main streaming thread.
(unlabeled) (of type source('a))

`on_track`

Call a given handler on new tracks.

Type:

(?id : string, (([string * string]) -> unit), source('a)) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type ([string * string]) -> unit): Function called on every beginning of track in the stream, with the corresponding metadata as argument. If there is no metadata at the beginning of track, the empty list is passed. That function should be fast because it is executed in the main streaming thread.
(unlabeled) (of type source('a))

`once`

Creates a source that plays only one track of the input source.

Type:

(source('a)) -> source('a)

Arguments:

(unlabeled) (of type source('a)): The input source.

`osd_metadata`

Use X On Screen Display to display metadata info.

Type:

(?color : string, ?position : string, ?font : string,
 ?display : (([string * string]) -> string), source('a)) ->
source('a)

Arguments:

color (of type string, which defaults to "green"): Color of the text.
position (of type string, which defaults to "top"): Position of the text (top|middle|bottom).
font (of type string, which defaults to "-*-courier-*-r-*-*-*-240-*-*-*-*-*-*"): Font used (xfontsel is your friend…)
display (of type ([string * string]) -> string, which defaults to <fun>): Function used to display a metadata packet.
(unlabeled) (of type source('a))

`overlap_sources`

Rotate between overlapping sources. Next track starts according to ‘liq_start_next’ offset metadata.

Type:

(?id : string, ?normalize : bool, ?start_next : string,
 ?weights : [int],
 [source(audio='#a, video='#b, midi=0)]) ->
source(audio='#a, video='#b, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
normalize (of type bool, which defaults to false)
start_next (of type string, which defaults to "liq_start_next"): Metadata field indicating when the next track should start, relative to current track’s time.
weights (of type [int], which defaults to []): Relative weight of the sources in the sum. The empty list stands for the homogeneous distribution.
(unlabeled) (of type [source(audio='#a, video='#b, midi=0)]): Sources to toggle from

`playlist.merge`

Play the whole playlist as one track.

Type:

(?id : string, ?random : bool, ?default_duration : float,
 ?length : float, ?conservative : bool, string) ->
source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
random (of type bool, which defaults to false): Randomize playlist content
default_duration (of type float, which defaults to 30.0): When unknown, assume this duration (in sec.) for files.
length (of type float, which defaults to 10.0): How much audio (in sec.) should be queued in advance.
conservative (of type bool, which defaults to false): If true, estimated remaining time on the current track is not considered when computing queue length.
(unlabeled) (of type string): Playlist URI.

`prepend`

Prepend an extra track before every track. Set the metadata ‘liq_prepend’ to ‘false’ to inhibit prepending on one track.

Type:

(?id : string, ?merge : bool, source(audio='#a,
 video='#b, midi='#c),
 (([string * string]) -> source(audio='#a, video='#b,
  midi='#c))) -> source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
merge (of type bool, which defaults to false): Merge the track with its appended track.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))
(unlabeled) (of type ([string * string]) -> source(audio='#a, video='#b, midi='#c)): Given the metadata, build the source producing the track to prepend. This source is allowed to fail (produce nothing) if no relevant track is to be appended. However, success must be immediate or it will not be taken into account.

`random`

At the beginning of every track, select a random ready child.

Type:

(?id : string, ?override : string,
 ?replay_metadata : bool, ?track_sensitive : {bool},
 ?transition_length : float,
 ?transitions : [(source('b), source('b)) -> source('b)],
 ?weights : [{int}], [source('b)]) -> source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_transition_length"): Metadata field which, if present and containing a float, overrides the transition_length parameter.
replay_metadata (of type bool, which defaults to true): Replay the last metadata of a child when switching to it in the middle of a track.
track_sensitive (of type {bool}, which defaults to true): Re-select only on end of tracks.
transition_length (of type float, which defaults to 5.0): Maximun transition duration.
transitions (of type [(source('b), source('b)) -> source('b)], which defaults to []): Transition functions, padded with fun (x,y) -> y functions.
weights (of type [{int}], which defaults to []): Weights of the children (padded with 1), defining for each child the probability that it is selected.
(unlabeled) (of type [source('b)])

`rotate`

Rotate between the sources.

Type:

(?id : string, ?override : string,
 ?replay_metadata : bool, ?track_sensitive : {bool},
 ?transition_length : float,
 ?transitions : [(source('b), source('b)) -> source('b)],
 ?weights : [{int}], [source('b)]) -> source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_transition_length"): Metadata field which, if present and containing a float, overrides the transition_length parameter.
replay_metadata (of type bool, which defaults to true): Replay the last metadata of a child when switching to it in the middle of a track.
track_sensitive (of type {bool}, which defaults to true): Re-select only on end of tracks.
transition_length (of type float, which defaults to 5.0): Maximun transition duration.
transitions (of type [(source('b), source('b)) -> source('b)], which defaults to []): Transition functions, padded with fun (x,y) -> y functions.
weights (of type [{int}], which defaults to []): Weights of the children (padded with 1), defining for each child how many tracks are played from it per round, if that many are actually available.
(unlabeled) (of type [source('b)])

`rotate.merge`

Same operator as rotate but merges tracks from each sources. For instance, rotate.merge([intro,main,outro]) creates a source that plays a sequence [intro,main,outro] as single track and loops back.

Type:

(?id : string, ?track_sensitive : bool,
 ?transitions : [(source('a), source('a)) -> source('a)],
 ?weights : [{int}], [source('a)]) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
track_sensitive (of type bool, which defaults to true): Re-select only on end of tracks.
transitions (of type [(source('a), source('a)) -> source('a)], which defaults to []): Transition functions, padded with fun (x,y) -> y functions.
weights (of type [{int}], which defaults to []): Weights of the children (padded with 1), defining for each child how many tracks are played from it per round, if that many are actually available.
(unlabeled) (of type [source('a)]): Sequence of sources to be merged

`say_metadata`

Append speech-synthesized tracks reading the metadata.

Type:

(source(?A), ?pattern : string) -> source(?A)

Arguments:

(unlabeled) (of type source(?A)): The source to use
pattern (of type string, which defaults to "say:$(if $(artist),\"It was $(artist)$(if $(title),\\\", $(title)\\\").\")"): Pattern to use

`sequence`

Play only one track of every successive source, except for the last one which is played as much as available.

Type:

(?id : string, ?merge : bool, [source('a)]) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
merge (of type bool, which defaults to false): Merge tracks when advancing from one source to the next one. This will NOT merge consecutive tracks from the last source; see merge_tracks() if you need that too.
(unlabeled) (of type [source('a)])

`server.insert_metadata`

Register a server/telnet command to update a source’s metadata. Returns a new source, which will receive the updated metadata. The command has the following format: insert key1=“val1”,key2=“val2”,…

Type:

(?id : string, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source('a))

`skip_blank`

Skip track when detecting a blank.

Type:

(?id : string, ?threshold : float, ?max_blank : float,
 ?min_noise : float, ?track_sensitive : bool,
 source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
threshold (of type float, which defaults to -40.0): Power in decibels under which the stream is considered silent.
max_blank (of type float, which defaults to 20.0): Maximum silence length allowed, in seconds.
min_noise (of type float, which defaults to 0.0): Minimum duration of noise required to end silence, in seconds.
track_sensitive (of type bool, which defaults to true): Reset blank counter at each track.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`smooth_add`

Mixes two streams, with faded transitions between the state when only the normal stream is available and when the special stream gets added on top of it.

Type:

(?delay : float, ?p : float, normal : source(audio='#a,
 video='#b, midi=0), special : source(audio='#a,
 video='#b, midi=0)) -> source(audio='#a, video='#b,
midi=0)

Arguments:

delay (of type float, which defaults to 0.5): Delay before starting the special source.
p (of type float, which defaults to 0.2): Portion of amplitude of the normal source in the mix.
normal (of type source(audio='#a, video='#b, midi=0)): The normal source, which could be called the carrier too.
special (of type source(audio='#a, video='#b, midi=0)): The special source.

`source.dynamic`

Dynamically change the underlying source.

Type:

(?id : string, (() -> [source('a)])) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type () -> [source('a)])

This function is experimental.

`store_metadata`

Keep track of the last N metadata packets in the stream, and make the history available via a server command.

Type:

(?id : string, ?size : int, source('a)) -> source('a)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
size (of type int, which defaults to 10): Size of the history
(unlabeled) (of type source('a))

`strip_blank`

Make the source unavailable when it is streaming blank.

Type:

(?id : string, ?max_blank : float, ?min_noise : float,
 ?start_blank : bool, ?threshold : float,
 ?track_sensitive : bool, source(audio='#a, video='#b,
 midi='#c)) -> active_source(audio='#a, video='#b,
midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
max_blank (of type float, which defaults to 20.0): Maximum duration of silence allowed, in seconds.
min_noise (of type float, which defaults to 0.0): Minimum duration of noise required to end silence, in seconds.
start_blank (of type bool, which defaults to false): Start assuming we have blank.
threshold (of type float, which defaults to -40.0): Power in decibels under which the stream is considered silent.
track_sensitive (of type bool, which defaults to true): Reset blank counter at each track.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`switch`

At the beginning of a track, select the first source whose predicate is true.

Type:

(?id : string, ?override : string,
 ?replay_metadata : bool, ?single : [bool],
 ?track_sensitive : {bool}, ?transition_length : float,
 ?transitions : [(source('b), source('b)) -> source('b)],
 [(() -> bool) * source('b)]) -> source('b)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
override (of type string, which defaults to "liq_transition_length"): Metadata field which, if present and containing a float, overrides the transition_length parameter.
replay_metadata (of type bool, which defaults to true): Replay the last metadata of a child when switching to it in the middle of a track.
single (of type [bool], which defaults to []): Forbid the selection of a branch for two tracks in a row. The empty list stands for [false,...,false].
track_sensitive (of type {bool}, which defaults to true): Re-select only on end of tracks.
transition_length (of type float, which defaults to 5.0): Maximun transition duration.
transitions (of type [(source('b), source('b)) -> source('b)], which defaults to []): Transition functions, padded with fun (x,y) -> y functions.
(unlabeled) (of type [(() -> bool) * source('b)]): Sources with the predicate telling when they can be played.

Source / Video Processing

`input.external.ffmpeg`

Input from ffmpeg.

Type:

(?id : string, ?show_command : bool, ?restart : bool,
 ?restart_on_error : bool, ?buffer : float, ?max : float,
 string) -> source(audio=2, video=1, midi=0)

Arguments:

id (of type string, which defaults to "")
show_command (of type bool, which defaults to false)
restart (of type bool, which defaults to true): restart on exit.
restart_on_error (of type bool, which defaults to false): restart on exit with error.
buffer (of type float, which defaults to 0.2): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.
(unlabeled) (of type string): ffmpeg options specifying the input

`video.add_image`

Add a static image on the first video channel.

Type:

(?id : string, ?width : int, ?height : int, ?x : int,
 ?y : int, file : 'a, source(audio='#b, video='#c,
 midi=0)) -> source(audio='#b, video='#c, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
width (of type int, which defaults to 0): Scale to width (zero means frame width, negative means original width).
height (of type int, which defaults to 0): Scale to height (zero means frame height, negative means original height).
x (of type int, which defaults to 4611686018427387903): x position.
y (of type int, which defaults to 4611686018427387903): y position.
file (of type 'a): Path to the image file.
(unlabeled) (of type source(audio='#b, video='#c, midi=0))

`video.add_text.gd`

Display a text.

Type:

(?id : string, ?color : int, ?cycle : bool,
 ?font : string, ?metadata : string, ?size : int,
 ?speed : int, ?x : {int}, ?y : {int}, {string},
 source(audio='#d, video='#e+1, midi='#f)) ->
source(audio='#d, video='#e+1, midi='#f)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
color (of type int, which defaults to 16777215): Text color (in 0xRRGGBB format).
cycle (of type bool, which defaults to true): Cycle text when it reaches left boundary.
font (of type string, which defaults to "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"): Path to ttf font file.
metadata (of type string, which defaults to ""): Change text on a particular metadata (empty string means disabled).
size (of type int, which defaults to 18): Font size.
speed (of type int, which defaults to 70): Horizontal speed in pixels per second (0 means no scrolling and update according to x and y in case they are variable).
x (of type {int}, which defaults to 10): x offset.
y (of type {int}, which defaults to 10): y offset.
(unlabeled) (of type {string}): Text to display.
(unlabeled) (of type source(audio='#d, video='#e+1, midi='#f))

`video.add_text.gstreamer`

Display a text.

Type:

(?id : string, ?color : int, ?cycle : bool,
 ?font : string, ?metadata : string, ?size : int,
 ?speed : int, ?x : {int}, ?y : {int}, {string},
 source(audio='#d, video='#e+1, midi='#f)) ->
source(audio='#d, video='#e+1, midi='#f)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
color (of type int, which defaults to 16777215): Text color (in 0xRRGGBB format).
cycle (of type bool, which defaults to true): Cycle text when it reaches left boundary.
font (of type string, which defaults to "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"): Path to ttf font file.
metadata (of type string, which defaults to ""): Change text on a particular metadata (empty string means disabled).
size (of type int, which defaults to 18): Font size.
speed (of type int, which defaults to 70): Horizontal speed in pixels per second (0 means no scrolling and update according to x and y in case they are variable).
x (of type {int}, which defaults to 10): x offset.
y (of type {int}, which defaults to 10): y offset.
(unlabeled) (of type {string}): Text to display.
(unlabeled) (of type source(audio='#d, video='#e+1, midi='#f))

`video.add_text.native`

Display a text.

Type:

(?id : string, ?color : int, ?cycle : bool,
 ?font : string, ?metadata : string, ?size : int,
 ?speed : int, ?x : {int}, ?y : {int}, {string},
 source(audio='#d, video='#e+1, midi='#f)) ->
source(audio='#d, video='#e+1, midi='#f)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
color (of type int, which defaults to 16777215): Text color (in 0xRRGGBB format).
cycle (of type bool, which defaults to true): Cycle text when it reaches left boundary.
font (of type string, which defaults to "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"): Path to ttf font file.
metadata (of type string, which defaults to ""): Change text on a particular metadata (empty string means disabled).
size (of type int, which defaults to 18): Font size.
speed (of type int, which defaults to 70): Horizontal speed in pixels per second (0 means no scrolling and update according to x and y in case they are variable).
x (of type {int}, which defaults to 10): x offset.
y (of type {int}, which defaults to 10): y offset.
(unlabeled) (of type {string}): Text to display.
(unlabeled) (of type source(audio='#d, video='#e+1, midi='#f))

`video.external.testsrc`

ffmpeg’s test source video (useful for testing and debugging).

Type:

(?id : string, ?restart : bool, ?restart_on_error : bool,
 ?buffer : float, ?max : float) -> source(audio=2,
video=1, midi=0)

Arguments:

id (of type string, which defaults to "")
restart (of type bool, which defaults to true): restart on exit.
restart_on_error (of type bool, which defaults to false): restart on exit with error.
buffer (of type float, which defaults to 0.2): Duration of the pre-buffered data.
max (of type float, which defaults to 10.0): Maximum duration of the buffered data.

`video.fade.in`

Fade the beginning of tracks. Metadata ‘liq_video_fade_in’ can be used to set the duration for a specific track (float in seconds).

Type:

(?id : string, ?duration : float, ?override : string,
 ?transition : string, ?type : string, source(audio='#a,
 video='#b+1, midi='#c)) -> source(audio='#a,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override.
override (of type string, which defaults to "liq_video_fade_in"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
transition (of type string, which defaults to "fade"): Kind of transition (fade|slide_left|slide_right|slide_up|slide_down|grow|disc|random).
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.fade.out`

Fade the end of tracks. Metadata ‘liq_video_fade_out’ can be used to set the duration for a specific track (float in seconds).

Type:

(?id : string, ?duration : float, ?override : string,
 ?transition : string, ?type : string, source(audio='#a,
 video='#b+1, midi='#c)) -> source(audio='#a,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type float, which defaults to 3.0): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override.
override (of type string, which defaults to "liq_video_fade_out"): Metadata field which, if present and containing a float, overrides the ‘duration’ parameter for current track.
transition (of type string, which defaults to "fade"): Kind of transition (fade|slide_left|slide_right|slide_up|slide_down|grow|disc|random).
type (of type string, which defaults to "lin"): Fader shape (lin|sin|log|exp): linear, sinusoidal, logarithmic or exponential.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.fill`

Fill frame with a color.

Type:

(?id : string, ?color : int, source(audio='#a,
 video='#b+1, midi='#c)) -> source(audio='#a,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
color (of type int, which defaults to 0): Color to fill the image with.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.frame.height`

Height for all video frames.

Type:

() -> int

Arguments:

`video.frame.rate`

Rate for all video frames.

Type:

() -> int

Arguments:

`video.frame.width`

Width for all video frames.

Type:

() -> int

Arguments:

`video.greyscale`

Convert video to greyscale.

Type:

(?id : string, source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.invert`

Invert video.

Type:

(?id : string, source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.lomo`

Emulate the “Lomo effect”.

Type:

(?id : string, source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.opacity`

Scale opacity of video.

Type:

(?id : string, float, source(audio='#a, video='#b+1,
 midi='#c)) -> source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type float): Coefficient to scale opacity with.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.opacity.blur`

Blur opacity of video.

Type:

(?id : string, source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.rotate`

Rotate video.

Type:

(?id : string, ?angle : {float}, ?speed : {float},
 source(audio='#c, video='#d+1, midi='#e)) ->
source(audio='#c, video='#d+1, midi='#e)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
angle (of type {float}, which defaults to 0.0): Initial angle in radians.
speed (of type {float}, which defaults to 3.14159265359): Rotation speed in radians per sec.
(unlabeled) (of type source(audio='#c, video='#d+1, midi='#e))

`video.scale`

Scale and translate video.

Type:

(?id : string, ?scale : float, ?x : int, ?xscale : float,
 ?y : int, ?yscale : float, source(audio='#a,
 video='#b+1, midi='#c)) -> source(audio='#a,
video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
scale (of type float, which defaults to 1.0): Scaling coefficient in both directions.
x (of type int, which defaults to 0): x offset.
xscale (of type float, which defaults to 1.0): x scaling.
y (of type int, which defaults to 0): y offset.
yscale (of type float, which defaults to 1.0): y scaling.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.sepia`

Convert video to sepia.

Type:

(?id : string, source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

`video.tile`

Tile sources (same as add but produces tiles of videos).

Type:

(?id : string, ?normalize : bool, ?proportional : bool,
 ?weights : [int],
 [source(audio='#a, video='#b+1, midi='#c)]) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
normalize (of type bool, which defaults to true)
proportional (of type bool, which defaults to true): Scale preserving the proportions.
weights (of type [int], which defaults to []): Relative weight of the sources in the sum. The empty list stands for the homogeneous distribution.
(unlabeled) (of type [source(audio='#a, video='#b+1, midi='#c)])

`video.transparent`

Set a color to be transparent.

Type:

(?id : string, ?color : int, ?precision : float,
 source(audio='#a, video='#b+1, midi='#c)) ->
source(audio='#a, video='#b+1, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
color (of type int, which defaults to 0): Color which should be transparent (in 0xRRGGBB format).
precision (of type float, which defaults to 0.0): Precision in color matching (0. means match precisely the color and 1. means match every color).
(unlabeled) (of type source(audio='#a, video='#b+1, midi='#c))

Source / Visualization

`peak`

Get current peak volume of the source. Returns a pair (f,s) where s is a new source and f is a function of type () -> float and returns the current peak volume of the source, with 0.0 <= peak volume <= 1.0. Some operators like amplify and compress can produce amplitudes greater than 1.0 if misconfigured, inducing clipping in the output.

Type:

(?id : string, ?duration : {float}, source(audio='#b,
 video='#c, midi='#d)) ->
(() -> float) * source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type {float}, which defaults to 0.5): Duration of the window (in seconds). A value <= 0, means that computation should not be performed.
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`peak.stereo`

Type:

(?id : string, ?duration : {float}, source(audio='#b+2,
 video='#c, midi='#d)) ->
(() -> float * float) * source(audio='#b+2, video='#c,
midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type {float}, which defaults to 0.5): Duration of the window (in seconds). A value <= 0, means that computation should not be performed.
(unlabeled) (of type source(audio='#b+2, video='#c, midi='#d))

`rms`

Get current RMS volume of the source. Returns a pair (f,s) where s is a new source and f is a function of type () -> float and returns the current RMS volume of the source, with 0.0 <= RMS volume <= 1.0. Some operators like amplify and compress can produce amplitudes greater than 1.0 if misconfigured, inducing clipping in the output.

Type:

(?id : string, ?duration : {float}, source(audio='#b,
 video='#c, midi='#d)) ->
(() -> float) * source(audio='#b, video='#c, midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type {float}, which defaults to 0.5): Duration of the window (in seconds). A value <= 0, means that computation should not be performed.
(unlabeled) (of type source(audio='#b, video='#c, midi='#d))

`rms.stereo`

Type:

(?id : string, ?duration : {float}, source(audio='#b+2,
 video='#c, midi='#d)) ->
(() -> float * float) * source(audio='#b+2, video='#c,
midi='#d)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
duration (of type {float}, which defaults to 0.5): Duration of the window (in seconds). A value <= 0, means that computation should not be performed.
(unlabeled) (of type source(audio='#b+2, video='#c, midi='#d))

`server.rms`

Type:

(?id : string, source(audio='#a, video='#b, midi='#c)) ->
source(audio='#a, video='#b, midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a, video='#b, midi='#c))

`video.volume`

Graphical visualization of the sound.

Type:

(?id : string, source(audio='#a+1, video=0, midi=0)) ->
source(audio='#a+1, video=1, midi=0)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
(unlabeled) (of type source(audio='#a+1, video=0, midi=0))

`vumeter`

VU meter (display the audio volume).

Type:

(?id : string, ?scroll : bool, source(audio='#a+1,
 video='#b, midi='#c)) -> source(audio='#a+1, video='#b,
midi='#c)

Arguments:

id (of type string, which defaults to ""): Force the value of the source ID.
scroll (of type bool, which defaults to false): Scroll.
(unlabeled) (of type source(audio='#a+1, video='#b, midi='#c))

String

`%`

pattern % [...,(k,v),...] changes in the pattern occurences of:

$(k) into v
`$(if $(k2),“a”,“b”) into “a” if k2 is found in the list, “b” otherwise.

Type:

(string, [string * string]) -> string

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type [string * string])

`^`

Concatenate strings.

Type:

(string, string) -> string

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type string)

`base64.decode`

Decode a Base64 encoded string.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`base64.encode`

Encode a string in Base64.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`bool_of_string`

Convert a string to a bool.

Type:

(?default : bool, string) -> bool

Arguments:

default (of type bool, which defaults to false)
(unlabeled) (of type string)

`float_of_string`

Convert a string to a float.

Type:

(?default : float, string) -> float

Arguments:

default (of type float, which defaults to 0.0)
(unlabeled) (of type string)

`int_of_string`

Convert a string to a int.

Type:

(?default : int, string) -> int

Arguments:

default (of type int, which defaults to 0)
(unlabeled) (of type string)

`json_of`

Convert a value to a json string.

Type:

(?compact : bool, 'a) -> string

Arguments:

compact (of type bool, which defaults to false): Output compact text.
(unlabeled) (of type 'a)

`of_json`

Parse a json string into a liquidsoap value. The value provided in the default parameter is quite important: only the part of the JSON data which has the same type as the default parameter will be kept (heterogeneous data cannot be represented in Liquidsoap because of typing). For instance, if the JSON j is

{
 "a": "test",
 "b": 5
}

the value returned by of_json(default=[("",0)], j) will be [("b",5)]: the pair ("a","test") is not kept because it is not of type string * int.

Type:

(default : 'a, string) -> 'a

Arguments:

default (of type 'a): Default value if string cannot be parsed.
(unlabeled) (of type string)

`string.capitalize`

Return a string with the first character set to upper case (capitalize), or to lower case (uncapitalize).

Type:

(?capitalize : bool, ?space_sensitive : bool, string) ->
string

Arguments:

capitalize (of type bool, which defaults to true): Capitalize if true, uncapitalize otherwise
space_sensitive (of type bool, which defaults to true): Capitalize each space separated sub-string.
(unlabeled) (of type string)

`string.case`

Convert a string to lower or upper case.

Type:

(?lower : bool, string) -> string

Arguments:

lower (of type bool, which defaults to true): Convert to lower case if true and uppercase otherwise.
(unlabeled) (of type string)

`string.concat`

Concatenate strings.

Type:

(?separator : string, [string]) -> string

Arguments:

separator (of type string, which defaults to "")
(unlabeled) (of type [string])

`string.contains`

Test whether a string contains a given prefix, substring or suffix.

Type:

(?prefix : string, ?substring : string, ?suffix : string,
 string) -> bool

Arguments:

prefix (of type string, which defaults to ""): Prefix to look for.
substring (of type string, which defaults to ""): Substring to look for.
suffix (of type string, which defaults to ""): Suffix to look for.
(unlabeled) (of type string): The string to look into.

`string.escape`

Escape special characters in a string. String is parsed char by char. See string.utf8.escape for an UTF8-aware parsing function.

Type:

(?special_chars : [string],
 ?escape_char : ((string) -> string), string) -> string

Arguments:

special_chars (of type [string], which defaults to ["\127", "\\", "\"", "\000", "\001", "\002", "\003", "\004", "\005", "\006", "\007", "\b", "\t", "\n", "\011", "\012", "\r", "\014", "\015", "\016", "\017", "\018", "\019", "\020", "\021", "\022", "\023", "\024", "\025", "\026", "\027", "\028", "\029", "\030", "\031"]): List of characters that should be escaped. The first character of each element in the list is considered.
escape_char (of type (string) -> string, which defaults to <fun>): Function used to escape a character.
(unlabeled) (of type string)

`string.extract`

Extract substrings from a string. Perl compatible regular expressions are recognized. Hence, special characters should be escaped. Returns a list of (index,value). If the list does not have a pair associated to some index, it means that the corresponding pattern was not found.

Type:

(pattern : string, string) -> [string * string]

Arguments:

pattern (of type string)
(unlabeled) (of type string)

`string.length`

Get the length of a string.

Type:

(string) -> int

Arguments:

(unlabeled) (of type string)

`string.match`

Match a string with an expression. Perl compatible regular expressions are recognized. Hence, special characters should be escaped.

Type:

(pattern : string, string) -> bool

Arguments:

pattern (of type string)
(unlabeled) (of type string)

`string.quote`

Escape shell metacharacters.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`string.recode`

Convert a string. Effective only if Camomile is enabled.

Type:

(?in_enc : string, ?out_enc : string, string) -> string

Arguments:

in_enc (of type string, which defaults to ""): Input encoding. Autodetected if empty.
out_enc (of type string, which defaults to "UTF-8"): Output encoding.
(unlabeled) (of type string)

`string.replace`

Replace substrings in a string. Will replace all substrings matched in the pattern by the string returned by the replace function.

Type:

(pattern : string, ((string) -> string), string) ->
string

Arguments:

pattern (of type string)
(unlabeled) (of type (string) -> string)
(unlabeled) (of type string)

`string.split`

Split a string at ‘separator’. Perl compatible regular expressions are recognized. Hence, special characters should be escaped.

Type:

(separator : string, string) -> [string]

Arguments:

separator (of type string)
(unlabeled) (of type string)

`string.sub`

Get a substring of a string. Returns “” if no such substring exists.

Type:

(string, start : int, length : int) -> string

Arguments:

(unlabeled) (of type string)
start (of type int): Return a sub string starting at this position. First position is 0.
length (of type int): Return a sub string of length characters.

`string.trim`

Return a string without leading and trailing whitespace.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`string.utf8.escape`

Escape special charaters in an UTF8 string.

Type:

(?special_chars : [string],
 ?escape_char : ((string) -> string), string) -> string

Arguments:

special_chars (of type [string], which defaults to ["\127", "\\", "\"", "\000", "\001", "\002", "\003", "\004", "\005", "\006", "\007", "\b", "\t", "\n", "\011", "\012", "\r", "\014", "\015", "\016", "\017", "\018", "\019", "\020", "\021", "\022", "\023", "\024", "\025", "\026", "\027", "\028", "\029", "\030", "\031"]): List of characters that should be escaped. The first character of each element in the list is considered.
escape_char (of type (string) -> string, which defaults to <fun>): Function used to escape a character.
(unlabeled) (of type string)

`string_of`

Return the representation of a value.

Type:

('a) -> string

Arguments:

(unlabeled) (of type 'a)

`string_of_metadata`

Standard function for displaying metadata. Shows artist and title, using “Unknown” when a field is empty.

Type:

([string * string]) -> string

Arguments:

(unlabeled) (of type [string * string]): Metadata packet to be displayed.

`url.decode`

Decode an encoded url (e.g. “%20” becomes ” “).

Type:

(?plus : bool, string) -> string

Arguments:

plus (of type bool, which defaults to true)
(unlabeled) (of type string)

`url.encode`

Encode an url (e.g. ” ” becomes “%20”).

Type:

(?plus : bool, string) -> string

Arguments:

plus (of type bool, which defaults to true)
(unlabeled) (of type string)

`url.split`

Split an url of the form foo?arg=bar&arg2=bar2 into (“foo”,[(“arg”,“bar”),(“arg2”,“bar2”)]).

Type:

(string) -> string * [string * string]

Arguments:

(unlabeled) (of type string): Url to split

`url.split_args`

Split the arguments of an url of the form arg=bar&arg2=bar2 into [(“arg”,“bar”),(“arg2”,“bar2”)].

Type:

(string) -> [string * string]

Arguments:

(unlabeled) (of type string): Agument string to split

System

`argv`

Get command-line parameters. The parameters are numbered starting from 1, the zeroth parameter being the script name.

Type:

(?default : string, int) -> string

Arguments:

default (of type string, which defaults to "")
(unlabeled) (of type int)

`environment`

Return the process environment.

Type:

() -> [string * string]

Arguments:

`exe_ext`

Executable file extension.

Type:

string

Arguments:

`exec_at`

Execute a given action when a predicate is true. This will be run in background.

Type:

(?freq : float, pred : (() -> bool), (() -> unit)) ->
unit

Arguments:

freq (of type float, which defaults to 1.0): Frequency for checking the predicate, in seconds.
pred (of type () -> bool): Predicate indicating when to execute the function, typically a time interval such as {10h-10h30}.
(unlabeled) (of type () -> unit): Function to execute when the predicate is true.

`exit`

Immediately stop the application. This should only be used in extreme cases or to specify an exit value. The recommended way of stopping Liquidsoap is to use shutdown.

Type:

(int) -> unit

Arguments:

(unlabeled) (of type int): Exit value.

`file.contents`

Read the whole contents of a file.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`file.exists`

Returns true if the file or directory exists.

Type:

(string) -> bool

Arguments:

(unlabeled) (of type string)

`file.extension`

Returns a file’s extension.

Type:

(?dir_sep : string, ?leading_dot : bool, string) ->
string

Arguments:

dir_sep (of type string, which defaults to "/"): Directory separator.
leading_dot (of type bool, which defaults to true): Return extension with a leading dot, e.g. .foo.
(unlabeled) (of type string)

`file.is_directory`

Returns true if the file exists and is a directory.

Type:

(string) -> bool

Arguments:

(unlabeled) (of type string)

`file.mime_default`

Alias of file.mime (because it is available)

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`file.read`

Read the content of a file. Returns a function of type ()->string. File is done reading when function returns the empty string "".

Type:

(string) -> () -> string

Arguments:

(unlabeled) (of type string)

`file.rmdir`

Remove a directory and its content.

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`file.size`

File size in bytes.

Type:

(string) -> int

Arguments:

(unlabeled) (of type string)

`file.temp`

Return a fresh temporary filename. The temporary file is created empty, with permissions 0o600 (readable and writable only by the file owner).

Type:

(string, string) -> string

Arguments:

(unlabeled) (of type string): File prefix
(unlabeled) (of type string): File suffix

`file.temp_dir`

Return a fresh temporary directory name. The temporary directory is created empty, with permissions 0o700 (readable, writable and listable only by the file owner).

Type:

(string, string) -> string

Arguments:

(unlabeled) (of type string): Directory prefix
(unlabeled) (of type string): Directory suffix

`file.unlink`

Remove a file.

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`file.watch`

Call a function when a file is modified. Returns unwatch function.

Type:

(string, (() -> unit)) -> () -> unit

Arguments:

(unlabeled) (of type string): File to watch.
(unlabeled) (of type () -> unit): Handler function.

`file.write`

Write data to a file. Returns true if successful.

Type:

(data : string, ?append : bool, ?perms : int, string) ->
bool

Arguments:

data (of type string): Data to write
append (of type bool, which defaults to false): Append data if file exists.
perms (of type int, which defaults to 420): Default file rights if created
(unlabeled) (of type string): Path to write to

`get_mime`

Generic mime test. First try to use file.mime if it exist. Otherwise try to get the value using the file binary. Returns “” (empty string) if no value can be found.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string): The file to test

`get_process_lines`

Perform a shell call and return the list of its output lines.

Type:

(?timeout : float, ?env : [string * string],
 ?inherit_env : bool, string) -> [string]

Arguments:

timeout (of type float, which defaults to -1.0): Cancel process after timeout has elapsed. Ignored if negative.
env (of type [string * string], which defaults to []): Process environment
inherit_env (of type bool, which defaults to true): Inherit calling process’s environment when env parameter is empty.
(unlabeled) (of type string): Command to run

`get_process_output`

Perform a shell call and return its output.

Type:

(?timeout : float, ?env : [string * string],
 ?inherit_env : bool, string) -> string

Arguments:

timeout (of type float, which defaults to -1.0): Cancel process after timeout has elapsed. Ignored if negative.
env (of type [string * string], which defaults to []): Process environment
inherit_env (of type bool, which defaults to true): Inherit calling process’s environment when env parameter is empty.
(unlabeled) (of type string): Command to run

`getenv`

Get the value associated to a variable in the process environment. Return “” if variable is not set.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`getopt`

Parse command line options: getopt("-o") returns “1” if “-o” was passed without any parameter, “0” otherwise. getopt(default="X","-o") returns “Y” if “-o Y” was passed, “X” otherwise. The result is removed from the list of arguments, affecting subsequent calls to argv() and getopt().

Type:

(?default : string, string) -> string

Arguments:

default (of type string, which defaults to "")
(unlabeled) (of type string)

`getpid`

Get the process’ pid.

Type:

() -> int

Arguments:

`gettimeofday`

Return the current time since 00:00:00 GMT, Jan. 1, 1970, in seconds.

Type:

() -> float

Arguments:

`gmtime`

Convert a time in seconds into a date in the UTC time zone and execute passed callback with the result. Fields meaning same as POSIX’s tm struct. Warning: “year” is: year - 1900, i.e. 117 for 2017!

Type:

(float,
 ((sec : int, min : int, hour : int, mday : int,
   mon : int, year : int, wday : int, yday : int,
   isdst : bool) -> 'a)) -> 'a

Arguments:

(unlabeled) (of type float)
(unlabeled) (of type (sec : int, min : int, hour : int, mday : int, mon : int, year : int, wday : int, yday : int, isdst : bool) -> 'a)

`localtime`

Convert a time in seconds into a date in the local time zone and execute passed callback with the result. Fields meaning same as POSIX’s tm struct. Warning: “year” is: year - 1900, i.e. 117 for 2017!

Type:

(float,
 ((sec : int, min : int, hour : int, mday : int,
   mon : int, year : int, wday : int, yday : int,
   isdst : bool) -> 'a)) -> 'a

Arguments:

(unlabeled) (of type float)
(unlabeled) (of type (sec : int, min : int, hour : int, mday : int, mon : int, year : int, wday : int, yday : int, isdst : bool) -> 'a)

`on_shutdown`

Type:

((() -> unit)) -> unit

Arguments:

(unlabeled) (of type () -> unit)

`on_start`

Type:

((() -> unit)) -> unit

Arguments:

(unlabeled) (of type () -> unit)

`os.type`

Type of OS running liquidsoap.

Type:

string

Arguments:

`path.basename`

Get the base name of a path.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`path.concat`

Concatenate two paths, using the appropriate directory separator.

Type:

(string, string) -> string

Arguments:

(unlabeled) (of type string)
(unlabeled) (of type string)

`path.dirname`

Get the directory name of a path.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`path.home.unrelate`

Expand path that start with ‘~’ with the current home directory.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`path.remove_extension`

Remove the file extension from a path.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`process.quote`

Return a quoted copy of the given string, suitable for use as one argument in a command line, escaping all meta-characters. Warning: under Windows, the output is only suitable for use with programs that follow the standard Windows quoting conventions.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)

`read`

Read some value from standard input (console).

Type:

(?hide : bool) -> string

Arguments:

hide (of type bool, which defaults to false): Hide typed characters (for passwords).

`reopen.stderr`

Reopen standard error on the given file

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`reopen.stdin`

Reopen standard input on the given file

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`reopen.stdout`

Reopen standard output on the given file

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`restart`

Restart the application.

Type:

() -> unit

Arguments:

`run_process`

Run a process in a shell environment. Returns: ((stdout,stderr,status) where status is one of: ("exit",""), ("killed","<signal number>"), ("stopped","<signal number>"), ("exception","<exception description>"), ("timeout","<run time>").

Type:

(?env : [string * string], ?inherit_env : bool,
 ?rwdirs : [string], ?rodirs : [string],
 ?network : string, ?timeout : float, string) ->
string * string * (string * string)

Arguments:

env (of type [string * string], which defaults to []): Process environment
inherit_env (of type bool, which defaults to true): Inherit calling process’s environment when env parameter is empty.
rwdirs (of type [string], which defaults to ["default"]): Read/write directories for sandboxing. "default" expands to sandbox default.
rodirs (of type [string], which defaults to ["default"]): Read-only directories for sandboxing. "default" expands to sandbox default.
network (of type string, which defaults to "default"): Enable or disable network inside sandboxed environment. One of: "default", "true" or "false". "default" is sandbox default.
timeout (of type float, which defaults to -1.0): Cancel process after timeout has elapsed. Ignored if negative.
(unlabeled) (of type string): Command to run

`setenv`

Set the value associated to a variable in the process environment.

Type:

(string, string) -> unit

Arguments:

(unlabeled) (of type string): Variable to be set.
(unlabeled) (of type string): Value to set.

`shutdown`

Shutdown the application.

Type:

() -> unit

Arguments:

`sleep`

Sleep for a given amount of seconds (beware that it freezes the thread executing it).

Type:

(float) -> unit

Arguments:

(unlabeled) (of type float): Number of seconds of sleep.

`source.is_up`

Check whether a source is up.

Type:

(source('a)) -> bool

Arguments:

(unlabeled) (of type source('a))

`source.on_shutdown`

Type:

(source('a), (() -> unit)) -> unit

Arguments:

(unlabeled) (of type source('a))
(unlabeled) (of type () -> unit)

`system`

Shell command call.

Type:

(string) -> unit

Arguments:

(unlabeled) (of type string)

`test_process`

Return true if process exited with 0 code.

Type:

(?timeout : float, ?env : [string * string],
 ?inherit_env : bool, string) -> bool

Arguments:

timeout (of type float, which defaults to -1.0): Cancel process after timeout has elapsed. Ignored if negative.
env (of type [string * string], which defaults to []): Process environment
inherit_env (of type bool, which defaults to true): Inherit calling process’s environment when env parameter is empty.
(unlabeled) (of type string): Command to test

`time`

Return the current time since 00:00:00 GMT, Jan. 1, 1970, in seconds.

Type:

() -> float

Arguments:

`which`

which(“progname”) searches for an executable named “progname” using directories from the PATH environment variable and returns “” if it could not find one.

Type:

(string) -> string

Arguments:

(unlabeled) (of type string)