index :: array

array.stretch

array time-stretch, pitch-shift or rate-change

available since version: 0.4

---

information

Based on SoundTouch library for changing the Tempo, Pitch and Playback Rates of arrays. Copies time-stretched data from source to destination array

arguments:

• SRC source array
  type: symbol
  

• DEST destination array
  type: symbol
  

properties:

• @src Get/set source array
  type: symbol
  

• @dest Get/set destination array
  type: symbol
  

• @tempo Get/set relative tempo change without affecting the sound pitch
  type: float
  units: %
  range: -50..100
  default: 0
  

• @pitch Get/set relative pitch change while keeping the original tempo
  type: float
  units: semitone
  default: 0
  

• @rate Get/set playback rate - changes both tempo and pitch together as if a vinyl disc was played at different RPM rate
  type: float
  range: 0.1..2
  default: 1
  

• @speech Get/set optimize for speech sound source
  type: bool
  default: 0
  

• @antialias Get/set use of anti-alias filter. Anti-alias filter is used to prevent folding of high frequencies when transposing the sample rate with interpolation.
  type: bool
  default: 0
  

• @aalength Get/set pitch transposer anti-alias filter length
  type: int
  range: 8..128
  default: 64
  

• @sequence Get/set Default length of a single processing sequence, in milliseconds. This determines to how long sequences the original sound is chopped in the time- stretch algorithm. The larger this value is, the lesser sequences are used in processing. In principle a bigger value sounds better when slowing down tempo, but worse when increasing tempo and vice versa. Increasing this value reduces computational burden & vice versa. Giving 0 value for the sequence length sets automatic parameter value according to tempo setting (recommended).
  type: int
  units: ms
  range: 0..100
  default: 0
  

• @seekwindow Get/set Seeking window default length in milliseconds for algorithm that finds the best possible overlapping location. This determines from how wide window the algorithm may look for an optimal joining location when mixing the sound sequences back together. The bigger this window setting is, the higher the possibility to find a better mixing position will become, but at the same time large values may cause a "drifting" artifact because consequent sequences will be taken at more uneven intervals. If there's a disturbing artifact that sounds as if a constant frequency was drifting around, try reducing this setting. Increasing this value increases computational burden & vice versa. Giving 0 value for the seek window length sets automatic parameter value according to tempo setting (recommended)
  type: int
  units: ms
  range: 0..100
  default: 0
  

• @overlap Get/set Overlap length in milliseconds. When the chopped sound sequences are mixed back together, to form a continuous sound stream, this parameter defines over how long period the two consecutive sequences are let to overlap each other. Increasing this value increases computational burden & vice versa.
  type: int
  units: ms
  range: 0..100
  default: 8
  

inlets:

• starts processing
  type: control

outlets:

• float value - number of result samples
  type: control

keywords:

array stretch

Authors: Olli Parviainen, Serge Poltavsky

License: GPL3 or later