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 177. 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
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o downsamp.wav -W ;;; for file output any platform

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr	1

ifrq	= cpspch(p4)
ain	diskin2 "beats.wav", 1
aenv	follow	ain, .001	;take the amplitude every 1/1000th of a second
alow	tone	aenv, 25	;lowpass-filter (25 Hz) for a clean signal
kenv	downsamp alow
asig    pluck   kenv, ifrq, 15, 0, 1
	outs	asig, asig


i 1 0 2	 9
i 1 + .	 7
i 1 + .	 5


See Also

diff, integ, interp, samphold, upsamp