Envelope
Description
An envelope is a time-variant control signal which can be used to control parameters of sounds that are to change over time (e.g. amplitude, frequency, filter characteristics, modulation amount, etc.).
Envelope Items use a function defined by a set of points in time-level space described by an array of DataTimePairs (defined in audio.h). The function is a continuous set of line segments drawn between the points in the DataTimePair array.
Envelopes are used in conjunction with Instruments that accept the Envelope Item's data and output the control signal (e.g. envelope.dsp).
Folio
Item Type
Create
CreateEnvelope()
CreateItem()
Delete
DeleteEnvelope()
DeleteItem()
Query
Modify
Use
AF_TAG_MICROSPERUNIT (int32) Create, Modify. Number of microseconds for each time unit specified in DataTimePairs and time related envelope tags. Defaults to 1000 on creation, which sets each time unit equal to one millisecond.
AF_TAG_RELEASEBEGIN (int32) Create, Modify. Index in DataTimePair array for beginning of release loop. -1 indicates no loop, which is the default on creation. If not -1, must ⇐ the value set by AF_TAG_RELEASEEND.
AF_TAG_RELEASEEND (int32) Create, Modify. Index in DataTimePair array for end of release loop. -1 indicates no loop, which is the default on creation. If not -1, must >= the value set by AF_TAG_RELEASEBEGIN.
AF_TAG_RELEASEJUMP (int32) Create, Modify. Index in DataTimePair array to jump to on release. When set, release causes escape from normal envelope processing to the specified index without disturbing the current output envelope value. From there, the envelope proceeds to the next DataTimePair from the current value. -1 to disable, which is the default on creation.
AF_TAG_SUSTAINBEGIN (int32) Create, Modify. Index in DataTimePair array for beginning of sustain loop. -1 indicates no loop, which is the default on creation. If not -1, ⇐ the value set by AF_TAG_SUSTAINEND.
AF_TAG_SUSTAINEND (int32) Create, Modify. Index in DataTimePair array for end of sustain loop. -1 indicates no loop, which is the default on creation. If not -1, >= the value set by AF_TAG_SUSTAINBEGIN.
Flags
See Also