\" $NetBSD: audioctl.1,v 1.26 2025/06/03 19:31:25 kre Exp $

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\" Author: Lennart Augustsson and Charles M. Hannum
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Dd June 3, 2025
Dt AUDIOCTL 1
Os
Sh NAME
Nm audioctl
Nd control software audio format
Sh SYNOPSIS
Nm
Op Fl n
Op Fl d Ar device
Fl a
Nm
Op Fl n
Op Fl d Ar device
Ar name ...
Nm
Op Fl n
Op Fl d Ar device
Fl w
Ar name=value ...
Sh DESCRIPTION
The
Nm
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
Xr audio 4
API is not available, e.g. when playing or recording raw audio data from a
Xr sh 1
script, or from the command line.
It does not control the underlying hardware format, which can be
changed with
Xr audiocfg 1 .
Pp
The variables that can be inspected and changed with
Nm
are normally per-application and are reset when a
Pa /dev/audioX
device is opened.
This can be circumvented by using
Pa /dev/soundX
instead, which retains global state.
Pp
If a list of variables is present on the command line, then
Nm
prints the current value of those variables for the specified device.
If the
Fl a
flag is specified, all variables for the device are printed.
If the
Fl w
flag is specified
Nm
attempts to set the specified variables to the given values.
Pp
The
Fl d
flag can be used to give an alternative audio control device.
The default can be set using the
Ev AUDIOCTLDEVICE
variable in the environment,
or set for the system using
Xr audiocfg 1 ,
or if neither of those applies is
Pa /dev/audioctl0 .
Pp
The
Fl n
flag suppresses printing of the variable name.
Sh ENVIRONMENT
Bl -tag -width AUDIOCTLDEVICE
It Ev AUDIOCTLDEVICE
the audio control device to use,
unless overridden by
Fl d .
El
Sh FILES
Bl -tag -width /dev/audioctl0 -compact
It Pa /dev/audio
a symlink indicating the default audio device
It Pa /dev/audio0
state resetting audio I/O device
(others: audio1, audio2, ...)
It Pa /dev/sound
a symlink indicating the default sound device
It Pa /dev/sound0
state retaining audio I/O device
(also sound1, sound2, ...)
It Pa /dev/audioctl
a symlink indicating the default audio control device
It Pa /dev/audioctl0
audio control device
(and audioctl1, audioctl2, ...)
El
Pp
The
Pa /dev/audioN ,
Pa /dev/soundN ,
and
Pa /dev/audioctlN ,
devices with the same value of
Pa N
refer to the same audio stream.
Different values for
Pa N
refer to different audio streams,
which may use different parameters.
Sh EXAMPLES
To set the playing sampling rate to 11025, you can use
Dl audioctl -w play.sample_rate=11025
To set all of the play parameters for CD-quality audio, you can use
Dl audioctl -w play=44100,2,16,slinear_le
Sh COMPATIBILITY
The old
Fl f
flag is still supported.
This support will be removed eventually.
Sh SEE ALSO
Xr audiocfg 1 ,
Xr audioplay 1 ,
Xr audiorecord 1 ,
Xr mixerctl 1 ,
Xr audio 4 ,
Xr sysctl 8
Sh HISTORY
The
Nm
command first appeared in
Nx 1.3 .
Sh CAVEATS
Since the parameters controlled by
Nm
are global, they can be changed unexpectedly if another application
uses the same audio device.
Pp
It is always preferable to use
Dv AUDIO_SETINFO
on a per-process
Pa /dev/audioX
device, if the
Xr audio 4
ioctls are available in the programming environment.
Similarly,
Xr audioplay 1
and
Xr audiorecord 1
are more safe for use in scripting.