audioctl(1) - NetBSD Manual Pages

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AUDIOCTL(1)             NetBSD General Commands Manual             AUDIOCTL(1)


NAME

     audioctl -- control software audio format


SYNOPSIS

     audioctl [-n] [-d device] -a
     audioctl [-n] [-d device] name ...
     audioctl [-n] [-d device] -w name=value ...


DESCRIPTION

     The audioctl command displays or sets the parameters that determine the
     playback and recording format for software using an audio device.  It is
     most useful when the full audio(4) API is not available, e.g. when play-
     ing or recording raw audio data from a sh(1) script, or from the command
     line.  It does not control the underlying hardware format, which can be
     changed with audiocfg(1).

     The variables that can be inspected and changed with audioctl are nor-
     mally per-application and are reset when a /dev/audioX device is opened.
     This can be circumvented by using /dev/soundX instead, which retains
     global state.

     If a list of variables is present on the command line, then audioctl
     prints the current value of those variables for the specified device.  If
     the -a flag is specified, all variables for the device are printed.  If
     the -w flag is specified audioctl attempts to set the specified variables
     to the given values.

     The -d flag can be used to give an alternative audio control device, the
     default is /dev/audioctl0.

     The -n flag suppresses printing of the variable name.


ENVIRONMENT

     AUDIOCTLDEVICE  the audio control device to use.


FILES

     /dev/sound0     audio I/O device
     /dev/audioctl0  audio control device


EXAMPLES

     To set the playing sampling rate to 11025, you can use
           audioctl -w play.sample_rate=11025
     To set all of the play parameters for CD-quality audio, you can use
           audioctl -w play=44100,2,16,slinear_le


COMPATIBILITY

     The old -f flag is still supported.  This support will be removed eventu-
     ally.


SEE ALSO

     audiocfg(1), audioplay(1), audiorecord(1), mixerctl(1), audio(4),
     sysctl(8)


HISTORY

     The audioctl command first appeared in NetBSD 1.3.


CAVEATS

     Since the parameters controlled by audioctl are global, they can be
     changed unexpectedly if another application uses the same audio device.

     It is always preferable to use AUDIO_SETINFO on a per-process /dev/audioX
     device, if the audio(4) ioctls are available in the programming environ-
     ment.  Similarly, audioplay(1) and audiorecord(1) are more safe for use
     in scripting.

NetBSD 9.4                      March 21, 2021                      NetBSD 9.4