downsamp — Modify a signal by down-sampling.


Modify a signal by down-sampling.


kres downsamp asig [, iwlen]


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 file downsamp.csd.

Example 121. Example of the downsamp opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

; Select audio/midi flags here according to platform
; Audio out   Audio in    No messages
-odac           -iadc     -d     ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o downsamp.wav -W ;;; for file output any platform

; 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


; Table #1, a sine wave.
f 1 0 16384 10 1

; Play Instrument #1 for one second.
i 1 0 1


See Also

diff, integ, interp, samphold, upsamp


Example written by Kevin Conder.