LV2 Parameters

ID	http://lv2plug.in/ns/ext/parameters
Version	1.4
Date	2020-03-20
Discuss	devel@lists.lv2plug.in (subscribe)

Index
History
API

This vocabulary describes parameters common in audio processing software. A parameter is purely a metadata concept, unrelated to any particular code mechanism. Parameters are used to assign meaning to controls (e.g. using lv2:designation for ports) so they can be used more intelligently or presented to the user more efficiently.

Index

Classes	Instances
ControlGroup CompressorControls EnvelopeControls FilterControls OscillatorControls	amplitude attack bypass cutoffFrequency decay delay dryLevel frequency gain hold pulseWidth ratio release resonance sampleRate sustain threshold waveform wetDryRatio wetLevel

Classes

CompressorControls

Class

Label

Compressor Controls

Subclass of

ControlGroup

Class

Label	Control Group
Subclass of	pg:Group
Superclass of	CompressorControls
	EnvelopeControls
	FilterControls
	OscillatorControls

A group representing a set of associated controls.

EnvelopeControls

Class

Label

DAHDSR Envelope Controls

Subclass of

ControlGroup

pg:element

lv2:designation	delay
lv2:index	0

pg:element

lv2:designation	attack
lv2:index	1

pg:element

lv2:designation	hold
lv2:index	2

pg:element

lv2:designation	decay
lv2:index	3

pg:element

lv2:designation	sustain
lv2:index	4

pg:element

lv2:designation	release
lv2:index	5

FilterControls

Class

Label

Filter Controls

Subclass of

OscillatorControls

Class

Label

Oscillator Controls

Subclass of

Instances

amplitude

Instance

Type	lv2:Parameter

attack

Instance

Type	lv2:Parameter

The duration of an envelope's attack stage.

bypass

Instance

Type	lv2:Parameter

A boolean parameter that disabled processing if true.

cutoffFrequency

Instance

Type	lv2:Parameter

decay

Instance

Type	lv2:Parameter

The duration of an envelope's decay stage.

delay

Instance

Type	lv2:Parameter

The duration of an envelope's delay stage.

dryLevel

Instance

Type	lv2:Parameter

The level of the unprocessed component of a signal.

frequency

Instance

Type	lv2:Parameter

gain

Instance

Type	lv2:Parameter
units:unit	units:db
lv2:default	0.0
lv2:maximum	20.0
lv2:minimum	-20.0

Gain in decibels.

hold

Instance

Type	lv2:Parameter

The duration of an envelope's hold stage.

pulseWidth

Instance

Type	lv2:Parameter

The width of a pulse of a rectangular waveform.

ratio

Instance

Type	lv2:Parameter

Compression ratio.

release

Instance

Type	lv2:Parameter

The duration of an envelope's release stage.

resonance

Instance

Type	lv2:Parameter

The resonance of a filter.

sampleRate

Instance

Type	lv2:Parameter

A sample rate in Hz.

sustain

Instance

Type	lv2:Parameter

The level (not duration) of an envelope's sustain stage.

threshold

Instance

Type	lv2:Parameter

Compression threshold.

waveform

Instance

Type	lv2:Parameter

wetDryRatio

Instance

Type	lv2:Parameter

The ratio between processed and bypass components in output signal. The dry and wet percentages can be calculated from the following equations:

    dry = (wetDryRatio.maximum - wetDryRatio.value) / wetDryRatio.maximum
    wet = wetDryRatio.value / wetDryRatio.maximum

Typically, maximum value of 1 or 100 and minimum value of 0 should be used.

wetLevel

Instance

Type	lv2:Parameter

The level of the processed component of a signal.

History

Version 1.4 (2015-04-07)

Add range to parameters so hosts know how to control them.

Version 1.2 (2012-10-14)

Use consistent label style.
Add param:sampleRate.
Add parameters.h of URI defines for convenience.

Version 1.0 (2012-04-17)

Initial release.