NAME

     sndioctl — manipulate audio device controls

SYNOPSIS

     sndioctl [-dimnqv] [-f device] [command ...]

DESCRIPTION

     The sndioctl utility can display or manipulate controls of sndio(7) audio devices, like the
     output level.  The options are as follows:

     -d      Dump the raw list of available controls and exit.  Useful as a debugging tool.

     -f device
             Use this sndio(7) audio device.

     -i      Display characteristics of requested controls instead of their values.

     -m      Monitor and display audio controls changes.

     -n      Suppress printing of the variable name.

     -q      Suppress all printing when setting a variable.

     -v      Enable verbose mode, a.k.a. multi-channel mode.  By default controls affecting
             different channels of the same stream are disguised as a single mono control to hide
             details that are not essential.

     If no commands are specified, all valid controls are displayed on stdout.  Unless -d, -m,
     -n, or -i are used, displayed lines are valid commands.  The set of available controls
     depends on the audio device.

     Commands use the following two formats to display and change controls respectively:

           [group/]stream[channel].function
           [group/]stream[channel].function=value

     On the left-hand side are specified the control group (if any), the affected stream name,
     and the optional channel number.  Examples of left-hand side terms:

           output.level
           output[0].level

     If the channel number (including the brackets) is omitted, the command is applied to all
     channels.

     Values are numbers between 0 and 1.  Two-state controls (switches) take either 0 or 1 as
     value, typically corresponding to the off and on states respectively.

     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 "!" is used instead of a number,
     then the switch is toggled.

EXAMPLES

     Increase the level control affecting all output channels by 10% of the maximum:

           $ sndioctl output.level=+0.1

     Mute all output channels:

           $ sndioctl output.mute=1

     Toggle the above mute control:

           $ sndioctl output.mute=!

     Allow audio recording and set all input channels to 50%:

           # sysctl kern.audio.record=1
           $ sndioctl input.mute=0 input.level=0.5

SEE ALSO

     sioctl_open(3)