iwlen (optional) -- window length in samples over which the audio signal is averaged to determine a downsampled value. Maximum length is ksmps; 0 and 1 imply no window averaging. The default value is 0.
downsamp converts an audio signal to a control signal by downsampling. It produces one kval for each audio control period. The optional window invokes a simple averaging process to suppress foldover.
Here is an example of the downsamp opcode. It uses the files downsamp.orc and downsamp.sco.
Example 1. Example of the downsamp opcode.
/* downsamp.orc */
; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
; Instrument #1.
instr 1
; Create a noise signal at a-rate.
anoise noise 20000, 0.2
; Downsample the noise signal to k-rate.
knoise downsamp anoise
; Use the noise signal at k-rate.
a1 oscil 30000, knoise, 1
out anoise
endin
/* downsamp.orc */
/* downsamp.sco */
; Table #1, a sine wave.
f 1 0 16384 10 1
; Play Instrument #1 for one second.
i 1 0 1
e
/* downsamp.sco */