.\" $OpenBSD: sndioctl.1,v 1.10 2020/04/21 13:24:29 ratchov Exp $
.\"
.\" Copyright (c) 2014-2020 Alexandre Ratchov <alex@caoua.org>
.\"
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.Dd $Mdocdate: April 21 2020 $
.Dt SNDIOCTL 1
.Os
.Sh NAME
.Nm sndioctl
.Nd control audio parameters
.Sh SYNOPSIS
.Nm
.Bk -words
.Op Fl dimnqv
.Op Fl f Ar device
.Op Ar command ...
.Ek
.Sh DESCRIPTION
The
.Nm
utility can display or change parameters of
.Xr sndio 7
audio devices.
The options are as follows:
.Bl -tag -width Ds
.It Fl d
Dump the raw list of available parameters and exit.
Useful as a debugging tool.
.It Fl f Ar device
Use this
.Xr sndio 7
audio device.
.It Fl i
Display characteristics of requested parameters
instead of their values.
.It Fl m
Monitor and display audio parameter changes.
.It Fl n
Suppress printing of the variable name.
.It Fl q
Suppress all printing when setting a variable.
.It Fl v
Enable verbose mode, a.k.a. multi-channel mode.
By default parameters affecting different channels
of the same stream are disguised as a single mono
parameter to hide details that are not essential.
.El
.Pp
If no commands are specified all valid parameters are displayed on
.Em stdout .
Unless
.Fl d ,
.Fl m ,
.Fl n ,
or
.Fl i
are used, displayed parameters are valid commands.
The set of available controls depends on the control device.
.Pp
Commands use the following two formats to display and set
parameters respectively:
.Pp
.Dl group/stream[channel].function
.Dl group/stream[channel].function=value
.Pp
On the left-hand side are specified the parameter group (if any),
the affected stream name, and the optional channel number.
Examples of left-hand side terms:
.Pp
.Dl output.level
.Dl output[0].level
.Pp
If the channel number (including the brackets) is omitted,
the command is applied to all channels.
.Pp
Values are numbers between 0 and 1.
Two-state controls (switches) take either 0 or 1 as value,
typically corresponding to the
.Em off
and
.Em on
states respectively.
.Pp
If a decimal is prefixed by the plus (minus) sign then
the given value is added to (subtracted from) the
current value of the control.
If
.Qq \&!
is used instead of a number, then the switch is toggled.
.Sh EXAMPLES
The following will set all
.Ar output
channels
.Ar level
control to zero:
.Pp
.Dl $ sndioctl output.level=0
.Pp
The following set all
.Ar output
channels
.Ar mute
control:
.Pp
.Dl $ sndioctl output.mute=0
.Sh SEE ALSO
.Xr sioctl_open 3