Version: 2.4.5

Source / Fade

`fade.skip`

Fade when the metadata trigger is received and then skip.

Type:

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

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.
delay (of type float, which defaults to 0.0): Initial delay before starting fade.
curve (of type float?, which defaults to null): Fade curve. Default if null.
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 the current track.
override_type (of type string, which defaults to "liq_fade_skip_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_skip_curve"): Metadata field which, if presents and correct, overrides the curve parameter for the current track. Use "default" to set to default value.
persist_overrides (of type bool, which defaults to false): Keep duration and type overrides on track change.
override_skip (of type string, which defaults to "liq_skip_meta"): Metadata field which, when present and set to "true", will trigger the fade
initial_metadata (of type [string * string], which defaults to []): Initial metadata.
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, 'b) where 'b is a set of tracks to be muxed into a source, 'a is a track and a track of type: pcm, pcm_s16 or pcm_f32)

Methods:

buffered (of type () -> [string * float]): Length of buffered data.
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 (?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.
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).{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).{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_frame (of type (?before : bool, synchronous : bool, (() -> unit)) -> 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)) -> 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)) -> 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)) -> 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)) -> unit): Call a given handler to be called when source shuts down
on_track (of type (synchronous : bool, (([string * string]) -> unit)) -> unit): Call a given handler on track marks
on_wake_up (of type (synchronous : bool, (() -> unit)) -> unit): Call a given handler to be called after the source is asked to get ready

`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.