Track / Audio processing

track.audio.add

Mix audio tracks with optional normalization.

Type:

(?id : string?, [pcm('a).{weight? : {float}}], ?normalize : {bool},
 ?power : {bool}) -> pcm('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type [pcm('a).{weight? : {float}}])
• normalize (of type {bool}, which defaults to true): Divide by the sum of weights of ready sources (or by the number of ready sources if weights are not specified).
• power (of type {bool}, which defaults to false): Perform constant-power normalization.

track.audio.amplify

Multiply the amplitude of the signal.

Type:

(?id : string?, ?override : {string?}, {float}, pcm*) -> pcm*

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• override (of type {string?}, which defaults to "liq_amplify"): Specify the name of a metadata field that, when present and well-formed, overrides the amplification factor for the current track. Well-formed values are floats in decimal notation (e.g. 0.7) which are taken as normal/linear multiplicative factors; values can be passed in decibels with the suffix dB (e.g. -8.2 dB, but the spaces do not matter). Defaults to settings.amplify.metadata. Set to null to disable.
• (unlabeled) (of type {float}): Multiplicative factor.
• (unlabeled) (of type anything that is a track of type: pcm, pcm_s16 or pcm_f32)

track.audio.clip

Clip samples, i.e. ensure that all values are between -1 and 1: values lower than -1 become -1 and values higher than 1 become 1. nan values become 0.

Type:

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

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm('a))

track.audio.comb

Comb filter.

Type:

(?id : string?, ?delay : float, ?feedback : {float}, pcm('a)) -> pcm('a)

Arguments:

• id (of type string?, which defaults to null): 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 pcm('a))

track.audio.compand

Compand the signal.

Type:

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

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• mu (of type float, which defaults to 1.0)
• (unlabeled) (of type source(pcm('a)))

track.audio.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}, pcm('a)) -> pcm('a)

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 pcm('a))

Methods:

• gain (of type () -> float): Gain (dB).
• rms (of type () -> float): RMS or peak power (linear).

track.audio.compress.exponential

Exponential compressor.

Type:

(?id : string?, ?mu : float, pcm('a)) -> pcm('a)

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 pcm('a))

track.audio.map

Map a function to all audio samples. This is SLOW!

Type:

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

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type (float) -> float)
• (unlabeled) (of type pcm('a))

This function is experimental.

track.audio.stereo.ms.decode

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

Type:

(?id : string?, ?width : float, pcm(stereo)) -> pcm(stereo)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• width (of type float, which defaults to 1.0): Width of the stereo field.
• (unlabeled) (of type pcm(stereo))

track.audio.stereo.ms.encode

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

Type:

(?id : string?, pcm(stereo)) -> pcm(stereo)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm(stereo))

track.audio.stereo.pan

Pan a stereo sound.

Type:

(?id : string?, ?field : {float}, {float}, pcm(stereo)) -> pcm(stereo)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• field (of type {float}, which defaults to 90.0): Field width in degrees (between 0 and 90).
• (unlabeled) (of type {float}): Pan value. Should be between -1 (left side) and 1 (right side).
• (unlabeled) (of type pcm(stereo))

track.audio.stereo.width

Spacializer which allows controlling the width of the signal.

Type:

(?id : string?, ?{float}, pcm(stereo)) -> pcm(stereo)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type {float}, which defaults to 0.0): Width of the signal (-1: mono, 0.: original, 1.: wide stereo).
• (unlabeled) (of type pcm(stereo))

track.audio.stereotool

Process the given audio track with StereoTool.

Type:

(?id : string?, library_file : string, ?license_key : string?,
 ?preset : string?, ?load_type : string, ?active : bool, pcm('a)) -> pcm('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• library_file (of type string): Path to the shared library file.
• license_key (of type string?, which defaults to null)
• preset (of type string?, which defaults to null): Path to a preset file to load when initializing the operator.
• load_type (of type string, which defaults to "totalinit"): Load type for preset. One of: "totalinit", "all_settings", "audiofm", "audio", "processing", "repair", "repair_no_pnr" or "sublevel_pnr".
• active (of type bool, which defaults to false): Set to true to keep the source streaming even when not actively used by an output.
• (unlabeled) (of type pcm('a))

Methods:

• api_version (of type () -> int): API version.
• latency (of type () -> float): Get the operator's latency.
• software_version (of type () -> int): Software version.
• unlincensed_used_features (of type () -> string?): Check if the license is valid for the current settings.
• valid_license (of type () -> bool): Check if the license is valid for the current settings.

track.audio.stretch

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

Type:

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

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• ratio (of type {float}): A value higher than 1 means slowing down.
• (unlabeled) (of type pcm('a))

track.decode.audio.pcm_f32

Decode an audio track using PCM signed 16 bit integers.

Type:

(?id : string?, pcm_f32('a)) -> pcm('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm_f32('a))

track.decode.audio.pcm_s16

Decode an audio track using PCM signed 16 bit integers.

Type:

(?id : string?, pcm_s16('a)) -> pcm('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm_s16('a))

track.encode.audio.pcm_f32

Encode an audio track using PCM signed 16 bit integers.

Type:

(?id : string?, pcm('a)) -> pcm_f32('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm('a))

track.encode.audio.pcm_s16

Encode an audio track using PCM signed 16 bit integers.

Type:

(?id : string?, pcm('a)) -> pcm_s16('a)

Arguments:

• id (of type string?, which defaults to null): Force the value of the track ID.
• (unlabeled) (of type pcm('a))