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)

Debian                                             $Mdocdate$                                        SNDIOCTL(1)