filenchnls
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## filenchnls

filenchnls — Returns the number of channels in a sound file.

## Description

Returns the number of channels in a sound file.

## Syntax

    ir filenchnls ifilcod [, iallowraw]

## Initialization

ifilcod -- sound file to be queried

iallowraw -- (Optional) Allow raw sound files (default=1)

## Performance

filenchnls returns the number of channels in the sound file ifilcod. filechnls can return the number of channels of convolve and PVOC files if the iallowraw flag is not zero (it is non-zero by default).

## Examples

Here is an example of the filenchnls opcode. It uses the file filenchnls.csd, fox.wav, and kickroll.wav.

Example 251. Example of the filenchnls 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 filechnls.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

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

    instr 1 ; choose between mono or stereo file

    ilen   filelen p4	;calculate length of soundfile
    ;print  ilen
    ichn filenchnls  p4	;check number of channels
    print  ichn

    if (ichn == 1) then
    ;mono signal
    asig diskin2 p4, 1
         outs    asig, asig

    else
    ;stereo signal
    aL, aR diskin2 p4, .5, 0, 1
           outs    aL, aR

    endif

    endin
    </CsInstruments>
    <CsScore>

    i 1 0 3 "fox.wav"	;mono signal
    i 1 5 2 "kickroll.wav"	;stereo signal

    e
    </CsScore>
    </CsoundSynthesizer>

The audio file “fox.wav” is monoaural (1 channel), while “kickroll.wav” is stereo (2 channels) So filenchnls's output should include lines like this:

    instr 1:  ichn = 1.000
    instr 1:  ichn = 2.000

## See Also

filebit, filelen, filepeak, filesr

## Credits

Author: Matt Ingalls
July 1999

New in Csound version 3.57

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