Source / Audio processing

accelerate

Accelerate a stream by dropping frames. This is useful for testing scripts.

Type:

(?id : string?, ?randomize : {float}, ?ratio : {float}, source('a)) ->
source('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the source ID.
• randomize (of type {float}, which defaults to 1.0): Randomization (0 means no randomization).
• ratio (of type {float}, which defaults to 2.0): A value higher than 1 means speeding up.
• (unlabeled) (of type source('a))

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.
• 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

This function is experimental.

bass_boost

Add some bass to the sound.

Type:

(?frequency : {float}, ?gain : {float}, source(audio=pcm('a), 'b)) ->
source(audio=pcm('a), 'b)
where
  'b is a set of internal tracks and a set of tracks to be muxed into a source

Arguments:

• frequency (of type {float}, which defaults to 200.0): Frequency below which sound is considered as bass.
• gain (of type {float}, which defaults to 10.0): Amount of boosting (dB).
• (unlabeled) (of type source(audio=pcm('a), 'b) where 'b is a set of internal tracks and a set of tracks to be muxed into a source): Source whose bass should be boosted

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.
• 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

comb

Comb filter

Type:

(?id : string?, ?delay : float, ?feedback : {float}, source(audio=pcm('a),
 'b)) -> source(audio=pcm('a), 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• id (of type string?, which defaults to "comb"): Force the value of the track 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=pcm('a), 'b) where 'b is a set of tracks to be muxed into a source)

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.
• 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

compand

Compand the signal.

Type:

(?id : string?, ?mu : float, source(audio=source(pcm('a)), 'b)) ->
source(audio=pcm('a), 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• id (of type string?, which defaults to "compand"): Force the value of the track ID.
• mu (of type float, which defaults to 1.0)
• (unlabeled) (of type source(audio=source(pcm('a)), 'b) where 'b is a set of tracks to be muxed into a source)

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.
• 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

compress

Compress the signal.

Type:

(?id : string?, ?attack : {float}, ?release : {float}, ?lookahead : {float},
 ?threshold : {float}, ?track_sensitive : bool, ?knee : {float},
 ?pre_gain : {float}, ?gain : {float}, ?ratio : {float}, ?window : {float},
 ?wet : {float}, source(audio=pcm('a), 'b)) -> source(audio=pcm('a)
.{gain? : never, rms? : never}, 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• attack (of type {float}, which defaults to 50.0): Attack time (ms).
• release (of type {float}, which defaults to 400.0): Release time (ms).
• lookahead (of type {float}, which defaults to 0.0): Lookahead (ms).
• threshold (of type {float}, which defaults to -10.0): Threshold level (dB).
• track_sensitive (of type bool, which defaults to false): Reset on every track.
• knee (of type {float}, which defaults to 1.0): Knee width (dB).
• pre_gain (of type {float}, which defaults to 0.0): Pre-amplification (dB).
• gain (of type {float}, which defaults to 0.0): Post-amplification (dB).
• ratio (of type {float}, which defaults to 2.0): Gain reduction ratio (reduction is ratio:1). Must be at least 1.
• window (of type {float}, which defaults to 0.0): RMS window length (second). 0. means peak mode.
• wet (of type {float}, which defaults to 1.0): How much of input sound to output (between 0 and 1, 0 means only original sound, 1 means only compressed sound).
• (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]): 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.
• fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
• gain (of type () -> float):
• 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`.
• rms (of type () -> float):
• 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

compress.exponential

Exponential compressor.

Type:

(?id : string?, ?mu : float, source(audio=pcm('a), 'b)) ->
source(audio=pcm('a), 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• mu (of type float, which defaults to 2.0): Exponential compression factor, typically greater than 1.
• (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]): 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.
• 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

compress.multiband

Multiband compression. The list in argument specifies

• the frequency below which we should apply compression (it is above previous band)
• the attack time (ms)
• the release time (ms)
• the compression ratio
• the threshold for compression
• the gain for the band

Type:

(?limit : bool, ?wet : {float}, source(audio=pcm('a), 'b),
 [
  {
    attack : {float},
    frequency : {float},
    gain : {float},
    ratio : {float},
    release : {float},
    threshold : {float}
  }]) -> source(audio=pcm('a).{gain? : never, rms? : never}, 'b)
where
  'b is a set of tracks to be muxed into a source and a set of internal tracks

Arguments:

• limit (of type bool, which defaults to true): Also apply limiting to bands.
• wet (of type {float}, which defaults to 1.0)
• (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): Parameters for compression bands.
• (unlabeled) (of type [ { attack : {float}, frequency : {float}, gain : {float}, ratio : {float}, release : {float}, threshold : {float} }]): Source on which multiband compression should be applied.

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.
• fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
• gain (of type () -> float):
• 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`.
• rms (of type () -> float):
• 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

dry_wet

Mix between dry and wet sources. Useful for testing effects. Typically:

c = interactive.float("wetness", min=0., max=1., 1.)
s = dry_wet(c, s, effect(s))

and vary c to hear the difference between the source without and with the effect.

Type:

(?power : bool, {float}, source('a), source('a)) -> source('a)
where 'a is a set of internal tracks

Arguments:

• power (of type bool, which defaults to false): If true use constant power mixing.
• (unlabeled) (of type {float}): Wetness coefficient, from 0 (fully dry) to 1 (fully wet).
• (unlabeled) (of type source('a) where 'a is a set of internal tracks): Dry source.
• (unlabeled) (of type source('a) where 'a is a set of internal tracks): Wet source.

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.
• 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

filter.iir.eq.low_high

A bandpass filter obtained by chaining a low-pass and a high-pass filter.

Type:

(?id : string?, low : {float}, high : {float}, ?q : float, source('a)) ->
source('a)

Arguments:

• id (of type string?, which defaults to null)
• low (of type {float}): Lower frequency of the bandpass filter.
• high (of type {float}): Higher frequency of the bandpass filter.
• q (of type float, which defaults to 1.0): Q factor.
• (unlabeled) (of type source('a)): Force the value of the source ID.

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.
• 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

helium

Increases the pitch, making voices sound like on helium.

Type:

(source(audio=pcm('a), 'b)) -> source(audio=pcm('a), 'b)

Arguments:

• (unlabeled) (of type source(audio=pcm('a), 'b)): The input source.

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.
• 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

limit

A limiter. This is a compress with tweaked parameters.

Type:

(?id : string?, ?attack : {float}, ?release : {float}, ?ratio : {float},
 ?threshold : {float}, ?pre_gain : {float}, ?gain : {float},
 source(audio=pcm('a), 'b)) -> source(audio=pcm('a)
.{gain? : never, rms? : never}, 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• id (of type string?, which defaults to null)
• attack (of type {float}, which defaults to 50.0)
• release (of type {float}, which defaults to 200.0)
• ratio (of type {float}, which defaults to 20.0)
• threshold (of type {float}, which defaults to -2.0)
• pre_gain (of type {float}, which defaults to 0.0)
• gain (of type {float}, which defaults to 0.0)
• (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]): 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.
• fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
• gain (of type () -> float):
• 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`.
• rms (of type () -> float):
• 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

mic_filter

Remove low frequencies often produced by microphones.

Type:

(?frequency : float, source(audio=pcm('a), 'b)) -> source(audio=pcm('a), 'b)

Arguments:

• frequency (of type float, which defaults to 200.0): Frequency under which sound should be lowered.
• (unlabeled) (of type source(audio=pcm('a), 'b)): The input source.

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.
• 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

mix

Mixing table controllable via source methods and optional server/telnet commands.

Type:

(?id : string?, ?register_server_commands : bool, ?normalize : bool,
 [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,
  'a is a track and a track of type: pcm, pcm_s16, pcm_f32, canvas, metadata or track_marks and a track of type: pcm, pcm_s16 or pcm_f32

Arguments:

• id (of type string?, which defaults to null): Force the value of the source ID.
• register_server_commands (of type bool, which defaults to true): Register corresponding server commands
• normalize (of type bool, which defaults to false): Normalize source's volume by the number of mixed sources.
• (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, 'a is a track and a track of type: pcm, pcm_s16, pcm_f32, canvas, metadata or track_marks 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.
• 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.
• inputs (of type [ { selected : (() -> bool) .{set : (bool) -> unit }, single : (() -> bool) .{set : (bool) -> unit }, source : source(audio='B, 'A), volume : (() -> float) .{set : (float) -> unit } }] where 'A is a set of tracks to be muxed into a source and a set of internal tracks, 'B is a track and a track of type: pcm, pcm_s16, pcm_f32, canvas, metadata or track_marks and a track of type: pcm, pcm_s16 or pcm_f32):
• 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

nrj

Compress and normalize, producing a more uniform and "full" sound.

Type:

(source(audio=pcm('a), 'b)) -> source(audio=pcm('a)
.{gain? : never, rms? : never}, 'b)
where 'b is a set of tracks to be muxed into a source

Arguments:

• (unlabeled) (of type source(audio=pcm('a), 'b) where 'b is a set of tracks to be muxed into a source): The input source.

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.
• fallible (of type bool): Indicate if a source may fail, i.e. may not be ready to stream.
• gain (of type () -> float):
• 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`.
• rms (of type () -> float):
• 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

sky

Multiband-compression.

Type:

(source(audio=pcm('a), 'b)) -> source(audio=pcm('a)
.{gain? : never, rms? : never}, 'b)
where
  'b is a set of internal tracks and a set of tracks to be muxed into a source

Arguments:

• (unlabeled) (of type source(audio=pcm('a), 'b) where 'b is a set of internal tracks and a set of tracks to be muxed into a source): The input source.

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.
• 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