downsamp
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## downsamp

downsamp — Modify a signal by down-sampling.

## Description

Modify a signal by down-sampling.

## Syntax

    kres downsamp asig [, iwlen]

## Initialization

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.

## Performance

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.

## Examples

Here is an example of the downsamp opcode. It uses the file downsamp.csd.

Example 187. Example of the downsamp opcode.

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

    <CsoundSynthesizer>
    <CsOptions>
    ; 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
    </CsOptions>
    <CsInstruments>

    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
    	endin

    </CsInstruments>
    <CsScore>

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

    e
    </CsScore>
    </CsoundSynthesizer>

## See Also

diff, integ, interp, samphold, upsamp

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