Version: 2.5.x (dev)

Source / Fade

`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?, ?duration : {float}, ?override_duration : string,
 ?persist_override : bool, ?width : float, ?deduplicate : bool,
 ((
   {
     db_level : float,
     metadata : [string * string],
     source : source(audio=pcm('a), 'b)
   }, 
   {
     db_level : float,
     metadata : [string * string],
     source : source(audio=pcm('a), 'b)
   }) -> source(audio=pcm('a), 'b)),
 source(audio=pcm('a), 'b)) -> source(audio=pcm('a), 'b)
where 'b is a set of tracks to be muxed into a source

Composition:

This source uses file composition by default.

Arguments:

id (of type string?, which defaults to null): Force the value of the source ID.
duration (of type {float}, which defaults to 5.0): Duration (in seconds) of buffered data from the end and start of each track that is used to compute the transition 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.
persist_override (of type bool, which defaults to false): Keep duration override on track change.
width (of type float, which defaults to 2.0): Width of the power computation window.
deduplicate (of type bool, which defaults to true): Crossfade transitions can generate duplicate metadata. When true, the operator removes duplicate metadata from the returned source.
(unlabeled) (of type ( { db_level : float, metadata : [string * string], source : source(audio=pcm('a), 'b) }, { db_level : float, metadata : [string * string], source : source(audio=pcm('a), 'b) }) -> source(audio=pcm('a), 'b) where 'b is a set of tracks to be muxed into a source): Transition function, composing from the end of a track and the next track. The sources corresponding to the two tracks are decorated with fields indicating the power of the signal before and after the transition (power), and the metadata (metadata).
(unlabeled) (of type source(audio=pcm('a), 'b) where 'b is a set of tracks to be muxed into a source)

Methods:

buffered (of type () -> [string * float]):
callbacks_count (of type () -> [string * int]): Callbacks a script has registered on this source, as pairs of callback name and count. A count that keeps growing is a function registering on a source it is handed without releasing what it registered.
clear_last_metadata (of type () -> unit): Clear the last metadata from the source.
clock (of type clock): The source's clock
cross_duration (of type () -> float):
duration (of type () -> float):
elapsed (of type () -> float): Elapsed time in the current track.
fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
id (of type () -> string): Identifier of the source.
insert_metadata (of type (?override : bool, ?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true. When override is false, metadata that the source provides itself takes precedence over the inserted one.
is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
log (of type {level : (() -> int).{exchange : (int) -> int, set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
remaining (of type () -> float): Estimation of remaining time in the current track.
reset_last_metadata_on_track (of type (() -> bool).{exchange : (bool) -> bool, set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
self_sync_description (of type () -> string):
skip (of type () -> unit): Skip to the next track.
time (of type () -> float): Get a source's time, based on its assigned clock.

Callbacks:

on_collect (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source is collected
on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> {release : () -> unit}): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler to execute on each metadata
on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
on_shutdown (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called after the source is asked to get ready

Composition methods:

composition_type (of type (() -> string).{exchange : (string) -> string, set : (string) -> unit}): This source uses file composition by default.
on_leave (of type ({source : source(audio=pcm('B), 'A), track_sensitive : bool}) -> unit where 'A is a set of tracks to be muxed into a source): Called after switching away from this source in a switch operator, once the transition using the ending source has completed. Receives a record with source (the source being left) and track_sensitive (true if the ending source's last frame had a track mark, i.e. it finished naturally; false if it was preempted mid-track). This function must return quickly as it runs in the streaming thread. The default depends on the active composition profile: file sources (source.composition.file) skip the source when preempted mid-track so it starts fresh on its next selection, and do nothing when it finished naturally; live sources (source.composition.live) do nothing.
on_select (of type ( { ending : source(audio=pcm('B), 'A)?, replay_metadata : bool, starting : source(audio=pcm('B), 'A) }) -> source(audio=pcm('B), 'A) where 'A is a set of tracks to be muxed into a source): Called when selecting this source in a switch operator. Receives a record with starting (the incoming source) and ending (the previous source, or null when the ending source reached a track boundary). Returns the source to use. By default, both file and live profiles fade out ending when non-null (up to 1 second). The default is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
replay_metadata (of type {bool}): Whether to replay the latest metadata on this source when it is selected in a switch operator. Defaults to true. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
single (of type bool): Forbid the selection of this source for two consecutive tracks in switch operators. Defaults to false.
track_sensitive (of type {bool}): Whether this source insists on track boundaries in switch operators: when true, it prefers not to be interrupted mid-track and not to be started mid-track. A switch may only cut into a track that is still playing when at least one of the two sources involved has track_sensitive set to false; otherwise it waits for the playing source to reach a track boundary. File-based sources default to true; live network and hardware inputs default to false. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).

`cross.simple`

Simple transition for crossfade

Type:

(?log : ((string) -> unit), ?fade_in : float, ?fade_out : float,
 ?initial_fade_in_metadata : [string * string],
 ?initial_fade_out_metadata : [string * string],
 ?ending_map : ((source(audio='a, 'b)) -> source(audio='a, 'b)),
 ?starting_map : ((source(audio='a, 'b)) -> source(audio='a, 'b)),
 source(audio='a, 'b), source(audio='a, 'b)) -> source(audio='a, 'b)
where
  'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type,
  'a is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks

Composition:

This source inherits composition from its effective source.

Arguments:

log (of type (string) -> unit, which defaults to fun (s) -> ...): Logging utility
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.
initial_fade_in_metadata (of type [string * string], which defaults to []): Initial fade-in metadata
initial_fade_out_metadata (of type [string * string], which defaults to []): Initial fade-out metadata
ending_map (of type (source(audio='a, 'b)) -> source(audio='a, 'b) where 'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'a is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks, which defaults to fun (s) -> ...): Optional mapping for the ending track
starting_map (of type (source(audio='a, 'b)) -> source(audio='a, 'b) where 'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'a is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks, which defaults to fun (s) -> ...): Optional mapping for the starting track
(unlabeled) (of type source(audio='a, 'b) where 'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'a is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks): Ending track
(unlabeled) (of type source(audio='a, 'b) where 'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'a is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks): Starting track

Methods:

buffered (of type () -> [string * float]): Length of buffered data.
callbacks_count (of type () -> [string * int]): Callbacks a script has registered on this source, as pairs of callback name and count. A count that keeps growing is a function registering on a source it is handed without releasing what it registered.
clear_last_metadata (of type () -> unit): Clear the last metadata from the source.
clock (of type clock): The source's clock
duration (of type () -> float): Estimation of the duration of the current track.
elapsed (of type () -> float): Elapsed time in the current track.
fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
id (of type () -> string): Identifier of the source.
insert_metadata (of type (?override : bool, ?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true. When override is false, metadata that the source provides itself takes precedence over the inserted one.
is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
log (of type {level : (() -> int).{exchange : (int) -> int, set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
remaining (of type () -> float): Estimation of remaining time in the current track.
reset_last_metadata_on_track (of type (() -> bool).{exchange : (bool) -> bool, set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
self_sync_description (of type () -> string):
skip (of type () -> unit): Skip to the next track.
time (of type () -> float): Get a source's time, based on its assigned clock.

Callbacks:

on_collect (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source is collected
on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> {release : () -> unit}): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler to execute on each metadata
on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
on_shutdown (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called after the source is asked to get ready

Composition methods:

composition_type (of type (() -> string).{exchange : (string) -> string, set : (string) -> unit}): This source inherits composition from its effective source.
on_leave (of type ({source : source(audio='B, 'A), track_sensitive : bool}) -> unit where 'A is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'B is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks): Called after switching away from this source in a switch operator, once the transition using the ending source has completed. Receives a record with source (the source being left) and track_sensitive (true if the ending source's last frame had a track mark, i.e. it finished naturally; false if it was preempted mid-track). This function must return quickly as it runs in the streaming thread. The default depends on the active composition profile: file sources (source.composition.file) skip the source when preempted mid-track so it starts fresh on its next selection, and do nothing when it finished naturally; live sources (source.composition.live) do nothing.
on_select (of type ( { ending : source(audio='B, 'A)?, replay_metadata : bool, starting : source(audio='B, 'A) }) -> source(audio='B, 'A) where 'A is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type, 'B is a track of type: pcm, pcm_s16 or pcm_f32 and a track and a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks): Called when selecting this source in a switch operator. Receives a record with starting (the incoming source) and ending (the previous source, or null when the ending source reached a track boundary). Returns the source to use. By default, both file and live profiles fade out ending when non-null (up to 1 second). The default is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
replay_metadata (of type {bool}): Whether to replay the latest metadata on this source when it is selected in a switch operator. Defaults to true. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
single (of type bool): Forbid the selection of this source for two consecutive tracks in switch operators. Defaults to false.
track_sensitive (of type {bool}): Whether this source insists on track boundaries in switch operators: when true, it prefers not to be interrupted mid-track and not to be started mid-track. A switch may only cut into a track that is still playing when at least one of the two sources involved has track_sensitive set to false; otherwise it waits for the playing source to reach a track boundary. File-based sources default to true; live network and hardware inputs default to false. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).

`crossfade`

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

Type:

(?id : string?, ?duration : {float}, ?override_duration : string,
 ?persist_override : bool, ?width : float, ?fade_in : float,
 ?fade_out : float, ?deduplicate : bool, source(audio=pcm('a), 'b)) ->
source(audio=pcm('a), 'b)
where
  'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type

Composition:

This source uses file composition by default.

Arguments:

id (of type string?, which defaults to null): Force the value of the source ID.
duration (of type {float}, which defaults to 5.0): Duration (in seconds) of buffered data from the end and start of each track that is used to compute the transition 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.
persist_override (of type bool, which defaults to false): Keep duration override on track change.
width (of type float, which defaults to 2.0): Width of the power computation window.
fade_in (of type float, which defaults to 3.0)
fade_out (of type float, which defaults to 3.0)
deduplicate (of type bool, which defaults to true): Crossfade transitions can generate duplicate metadata. When true, the operator removes duplicate metadata from the returned source.
(unlabeled) (of type source(audio=pcm('a), 'b) where 'b is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type): The input source.

Methods:

buffered (of type () -> [string * float]):
callbacks_count (of type () -> [string * int]): Callbacks a script has registered on this source, as pairs of callback name and count. A count that keeps growing is a function registering on a source it is handed without releasing what it registered.
clear_last_metadata (of type () -> unit): Clear the last metadata from the source.
clock (of type clock): The source's clock
cross_duration (of type () -> float):
duration (of type () -> float):
elapsed (of type () -> float): Elapsed time in the current track.
fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
id (of type () -> string): Identifier of the source.
insert_metadata (of type (?override : bool, ?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true. When override is false, metadata that the source provides itself takes precedence over the inserted one.
is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
log (of type {level : (() -> int).{exchange : (int) -> int, set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
remaining (of type () -> float): Estimation of remaining time in the current track.
reset_last_metadata_on_track (of type (() -> bool).{exchange : (bool) -> bool, set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
self_sync_description (of type () -> string):
skip (of type () -> unit): Skip to the next track.
time (of type () -> float): Get a source's time, based on its assigned clock.

Callbacks:

on_collect (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source is collected
on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> {release : () -> unit}): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler to execute on each metadata
on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
on_shutdown (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called after the source is asked to get ready

Composition methods:

composition_type (of type (() -> string).{exchange : (string) -> string, set : (string) -> unit}): This source uses file composition by default.
on_leave (of type ({source : source(audio=pcm('B), 'A), track_sensitive : bool}) -> unit where 'A is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type): Called after switching away from this source in a switch operator, once the transition using the ending source has completed. Receives a record with source (the source being left) and track_sensitive (true if the ending source's last frame had a track mark, i.e. it finished naturally; false if it was preempted mid-track). This function must return quickly as it runs in the streaming thread. The default depends on the active composition profile: file sources (source.composition.file) skip the source when preempted mid-track so it starts fresh on its next selection, and do nothing when it finished naturally; live sources (source.composition.live) do nothing.
on_select (of type ( { ending : source(audio=pcm('B), 'A)?, replay_metadata : bool, starting : source(audio=pcm('B), 'A) }) -> source(audio=pcm('B), 'A) where 'A is a set of tracks to be muxed into a source and a set of internal tracks and an orderable type): Called when selecting this source in a switch operator. Receives a record with starting (the incoming source) and ending (the previous source, or null when the ending source reached a track boundary). Returns the source to use. By default, both file and live profiles fade out ending when non-null (up to 1 second). The default is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
replay_metadata (of type {bool}): Whether to replay the latest metadata on this source when it is selected in a switch operator. Defaults to true. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
single (of type bool): Forbid the selection of this source for two consecutive tracks in switch operators. Defaults to false.
track_sensitive (of type {bool}): Whether this source insists on track boundaries in switch operators: when true, it prefers not to be interrupted mid-track and not to be started mid-track. A switch may only cut into a track that is still playing when at least one of the two sources involved has track_sensitive set to false; otherwise it waits for the playing source to reach a track boundary. File-based sources default to true; live network and hardware inputs default to false. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).

`fade.in`

Fade the beginning of tracks.

Type:

(?id : string, ?duration : float?, ?delay : float, ?curve : float?,
 ?override_duration : string, ?override_type : string,
 ?override_curve : string, ?override_delay : string,
 ?persist_overrides : bool, ?track_sensitive : bool,
 ?initial_metadata : [string * string], ?type : string?,
 source(audio='a, 'b)) -> source(audio='a, 'b)
where
  'a is a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks and a track and a track of type: pcm, pcm_s16 or pcm_f32,
  'b is an orderable type and a set of internal tracks and a set of tracks to be muxed into a source

Composition:

This source uses file composition by default.

Arguments:

id (of type string, which defaults to "fade.in"): Force the value of the source ID.
duration (of type float?, which defaults to null): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override. Defaults to settings.fade.in.duration if null.
delay (of type float, which defaults to 0.0): Initial delay before starting fade.
curve (of type float?, which defaults to null): Fade curve. Defaults to settings.fade.in.curve if null.
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 the current track.
override_type (of type string, which defaults to "liq_fade_in_type"): Metadata field which, if present and correct, overrides the 'type' parameter for the current track.
override_curve (of type string, which defaults to "liq_fade_in_curve"): Metadata field which, if presents and correct, overrides the curve parameter for the current track. Use "default" to set to default value.
override_delay (of type string, which defaults to "liq_fade_in_delay"): Metadata field which, if presents and correct, overrides the initial fade delay.
persist_overrides (of type bool, which defaults to false): Keep duration and type overrides on track change.
track_sensitive (of type bool, which defaults to false): Be track sensitive (if false we only fade in once at the beginning of the track).
initial_metadata (of type [string * string], which defaults to []): Initial metadata.
type (of type string?, which defaults to null): Fader shape. One of: "lin"", "sin", "log" or "exp". Defaults to settings.fade.in.type if null.
(unlabeled) (of type source(audio='a, 'b) where 'a is a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks and a track and a track of type: pcm, pcm_s16 or pcm_f32, 'b is an orderable type and a set of internal tracks and a set of tracks to be muxed into a source)

Methods:

buffered (of type () -> [string * float]): Length of buffered data.
callbacks_count (of type () -> [string * int]): Callbacks a script has registered on this source, as pairs of callback name and count. A count that keeps growing is a function registering on a source it is handed without releasing what it registered.
clear_last_metadata (of type () -> unit): Clear the last metadata from the source.
clock (of type clock): The source's clock
duration (of type () -> float): Estimation of the duration of the current track.
elapsed (of type () -> float): Elapsed time in the current track.
fade_delay (of type () -> float):
fade_duration (of type () -> float):
fade_type (of type () -> string):
fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
id (of type () -> string): Identifier of the source.
insert_metadata (of type (?override : bool, ?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true. When override is false, metadata that the source provides itself takes precedence over the inserted one.
is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
log (of type {level : (() -> int).{exchange : (int) -> int, set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
remaining (of type () -> float): Estimation of remaining time in the current track.
reset_last_metadata_on_track (of type (() -> bool).{exchange : (bool) -> bool, set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
self_sync_description (of type () -> string):
skip (of type () -> unit): Skip to the next track.
time (of type () -> float): Get a source's time, based on its assigned clock.

Callbacks:

on_collect (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source is collected
on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> {release : () -> unit}): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler to execute on each metadata
on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
on_shutdown (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called after the source is asked to get ready

Composition methods:

composition_type (of type (() -> string).{exchange : (string) -> string, set : (string) -> unit}): This source uses file composition by default.
on_leave (of type ({source : source(audio='B, 'A), track_sensitive : bool}) -> unit where 'B is a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks and a track and a track of type: pcm, pcm_s16 or pcm_f32, 'A is an orderable type and a set of internal tracks and a set of tracks to be muxed into a source): Called after switching away from this source in a switch operator, once the transition using the ending source has completed. Receives a record with source (the source being left) and track_sensitive (true if the ending source's last frame had a track mark, i.e. it finished naturally; false if it was preempted mid-track). This function must return quickly as it runs in the streaming thread. The default depends on the active composition profile: file sources (source.composition.file) skip the source when preempted mid-track so it starts fresh on its next selection, and do nothing when it finished naturally; live sources (source.composition.live) do nothing.
on_select (of type ( { ending : source(audio='B, 'A)?, replay_metadata : bool, starting : source(audio='B, 'A) }) -> source(audio='B, 'A) where 'B is a track of type: pcm, pcm_s16, pcm_f32, yuv420p, metadata or track_marks and a track and a track of type: pcm, pcm_s16 or pcm_f32, 'A is an orderable type and a set of internal tracks and a set of tracks to be muxed into a source): Called when selecting this source in a switch operator. Receives a record with starting (the incoming source) and ending (the previous source, or null when the ending source reached a track boundary). Returns the source to use. By default, both file and live profiles fade out ending when non-null (up to 1 second). The default is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
replay_metadata (of type {bool}): Whether to replay the latest metadata on this source when it is selected in a switch operator. Defaults to true. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
single (of type bool): Forbid the selection of this source for two consecutive tracks in switch operators. Defaults to false.
track_sensitive (of type {bool}): Whether this source insists on track boundaries in switch operators: when true, it prefers not to be interrupted mid-track and not to be started mid-track. A switch may only cut into a track that is still playing when at least one of the two sources involved has track_sensitive set to false; otherwise it waits for the playing source to reach a track boundary. File-based sources default to true; live network and hardware inputs default to false. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).

`fade.out`

Fade the end of tracks.

Type:

(?id : string, ?duration : float?, ?delay : float, ?curve : float?,
 ?override_duration : string, ?override_type : string,
 ?override_curve : string, ?override_delay : string,
 ?persist_overrides : bool, ?track_sensitive : bool,
 ?initial_metadata : [string * string], ?type : string?,
 source(audio='a, 'b)) -> source(audio='a, 'b)
where 'a is a track and a track of type: pcm, pcm_s16 or pcm_f32,
  'b is an orderable type and a set of tracks to be muxed into a source

Composition:

This source uses file composition by default.

Arguments:

id (of type string, which defaults to "fade.out"): Force the value of the source ID.
duration (of type float?, which defaults to null): Duration of the fading. This value can be set on a per-file basis using the metadata field passed as override. Defaults to settings.fade.out.curve if null.
delay (of type float, which defaults to 0.0): Initial delay before starting fade. Defaults to settings.fade.out.delay if null.
curve (of type float?, which defaults to null): Fade curve. Defaults to settings.fade.out.curve if null.
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 the current track.
override_type (of type string, which defaults to "liq_fade_out_type"): Metadata field which, if present and correct, overrides the 'type' parameter for the current track.
override_curve (of type string, which defaults to "liq_fade_out_curve"): Metadata field which, if presents and correct, overrides the curve parameter for the current track. Use "default" to set to default value.
override_delay (of type string, which defaults to "liq_fade_out_delay"): Metadata field which, if presents and correct, overrides the initial fade delay.
persist_overrides (of type bool, which defaults to false): Keep duration and type overrides on track change.
track_sensitive (of type bool, which defaults to false): Be track sensitive (if false we only fade ou once at the beginning of the track).
initial_metadata (of type [string * string], which defaults to []): Initial metadata.
type (of type string?, which defaults to null): Fader shape. One of: "lin"", "sin", "log" or "exp". Defaults to settings.fade.out.type if null.
(unlabeled) (of type source(audio='a, 'b) where 'a is a track and a track of type: pcm, pcm_s16 or pcm_f32, 'b is an orderable type and a set of tracks to be muxed into a source)

Methods:

buffered (of type () -> [string * float]): Length of buffered data.
callbacks_count (of type () -> [string * int]): Callbacks a script has registered on this source, as pairs of callback name and count. A count that keeps growing is a function registering on a source it is handed without releasing what it registered.
clear_last_metadata (of type () -> unit): Clear the last metadata from the source.
clock (of type clock): The source's clock
duration (of type () -> float): Estimation of the duration of the current track.
elapsed (of type () -> float): Elapsed time in the current track.
fade_duration (of type () -> float):
fade_type (of type () -> string):
fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
generate_frame (of type () -> unit): Generate a frame from the source without consuming it. This can be useful in advanced cases where generating a frame is required to trigger some side effect like calculating some metadata before making a decision. You should make sure that the source is available before calling this function and it should only be called inside synchronous streaming loop callback such as on_frame!
id (of type () -> string): Identifier of the source.
insert_metadata (of type (?override : bool, ?new_track : bool, [string * string]) -> unit): Dynamically insert metadata in a stream. Inserts a new track with the given metadata if new_track is true. When override is false, metadata that the source provides itself takes precedence over the inserted one.
is_active (of type () -> bool): true if the source is active, i.e. it is continuously animated by its own clock whenever it is ready. Typically, true for outputs and sources such as input.http.
is_ready (of type () -> bool): Indicate if a source is ready to stream. This does not mean that the source is currently streaming, just that its resources are all properly initialized.
is_up (of type () -> bool): Indicate that the source can be asked to produce some data at any time. This is true when the source is currently being used or if it could be used at any time, typically inside a switch or fallback.
last_metadata (of type () -> [string * string]?): Return the last metadata from the source.
log (of type {level : (() -> int).{exchange : (int) -> int, set : (int) -> unit}}): Get or set the source's log level, from 1 to 5.
register_command (of type (?usage : string?, description : string, string, ((string) -> string)) -> unit): Register a server command for this source. Command is registered under the source's id namespace when it gets up and de-registered when it gets down.
remaining (of type () -> float): Estimation of remaining time in the current track.
reset_last_metadata_on_track (of type (() -> bool).{exchange : (bool) -> bool, set : (bool) -> unit}): If true, the source's last_metadata is reset on each new track. If a metadata is present along with the track mark, then it becomes the new last_metadata, otherwise, last_metadata becomes null`.
seek (of type (float) -> float): Seek forward, in seconds (returns the amount of time effectively seeked).
self_sync (of type () -> bool): Is the source currently controlling its own real-time loop.
self_sync_description (of type () -> string):
skip (of type () -> unit): Skip to the next track.
time (of type () -> float): Get a source's time, based on its assigned clock.

Callbacks:

on_collect (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source is collected
on_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler on frame. When before is true, callback is executed before computing the frame and after otherwise
on_frame_checksum (of type (?before : ((string?) -> unit)?, synchronous : bool, ((cache : string?, string) -> unit)) -> {release : () -> unit}): Call a given handler Register callbacks to compute frame checksums for debugging purposes. This is useful to track frame content changes through the streaming pipeline. The before callback is called before computing the frame with the checksum of the cached frame (if any, null otherwise). The main callback is called after computing the frame with the checksum of the generated frame and the remaining cache (if any).
on_metadata (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler to execute on each metadata
on_position (of type (position : {float}, ?remaining : bool, ?allow_partial : bool, synchronous : bool, ((float, [string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track position. If remaining is false, callback is executed when position in track is more or equal to position. If remaining is true, callback is executed when remaining time in the current track is less or equal to position. Keep in mind that elapsed time is exact while remaining time is always estimated. Remaining time is usually more accurate for file-based sources. When allow_partial is true, if the current track ends before the offset position is reached, callback is still executed
on_shutdown (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> {release : () -> unit}): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> {release : () -> unit}): Call a given handler to be called after the source is asked to get ready

Composition methods:

composition_type (of type (() -> string).{exchange : (string) -> string, set : (string) -> unit}): This source uses file composition by default.
on_leave (of type ({source : source(audio='B, 'A), track_sensitive : bool}) -> unit where 'B is a track and a track of type: pcm, pcm_s16 or pcm_f32, 'A is an orderable type and a set of tracks to be muxed into a source): Called after switching away from this source in a switch operator, once the transition using the ending source has completed. Receives a record with source (the source being left) and track_sensitive (true if the ending source's last frame had a track mark, i.e. it finished naturally; false if it was preempted mid-track). This function must return quickly as it runs in the streaming thread. The default depends on the active composition profile: file sources (source.composition.file) skip the source when preempted mid-track so it starts fresh on its next selection, and do nothing when it finished naturally; live sources (source.composition.live) do nothing.
on_select (of type ( { ending : source(audio='B, 'A)?, replay_metadata : bool, starting : source(audio='B, 'A) }) -> source(audio='B, 'A) where 'B is a track and a track of type: pcm, pcm_s16 or pcm_f32, 'A is an orderable type and a set of tracks to be muxed into a source): Called when selecting this source in a switch operator. Receives a record with starting (the incoming source) and ending (the previous source, or null when the ending source reached a track boundary). Returns the source to use. By default, both file and live profiles fade out ending when non-null (up to 1 second). The default is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
replay_metadata (of type {bool}): Whether to replay the latest metadata on this source when it is selected in a switch operator. Defaults to true. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).
single (of type bool): Forbid the selection of this source for two consecutive tracks in switch operators. Defaults to false.
track_sensitive (of type {bool}): Whether this source insists on track boundaries in switch operators: when true, it prefers not to be interrupted mid-track and not to be started mid-track. A switch may only cut into a track that is still playing when at least one of the two sources involved has track_sensitive set to false; otherwise it waits for the playing source to reach a track boundary. File-based sources default to true; live network and hardware inputs default to false. The value is looked up at runtime from the active composition profile (source.composition.file or source.composition.live depending on composition_type).

`mkfade`

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

Type:

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

Arguments:

curve (of type float?, which defaults to null): Fade curve for "log" and "exp" shapes. If null, depends on the type of fade. The higher the value, the shaper the curve.
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.
delay (of type float, which defaults to 0.0): Initial delay before starting fade.
duration (of type float, which defaults to 3.0): Duration in seconds.
on_done (of type () -> unit, which defaults to {()}): Function to execute when the fade is finished
(unlabeled) (of type source('a))

cross​

cross.simple​

crossfade​

fade.in​

fade.out​

mkfade​

`cross`

`cross.simple`

`crossfade`

`fade.in`

`fade.out`

`mkfade`