Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
vmixctl(8)		System Administration Commands		    vmixctl(8)

NAME
       vmixctl - Open Sound System utility to control the vmix subsystem.

SYNOPSIS
       o       vmixctl attach [attach_options...] audiodev [inputdev]
       o       vmixctl detach [attach_options...] audiodev
       o       vmixctl rate audiodev samplerate
       o       vmixctl remap audiodev channels

DESCRIPTION
       The  vmixctl  program can be used to attach or detach the virtual mixer
       subsystem (vmix)	to/from	audio devices. In addition it can be  used  to
       control	vmix  related  parameters such as the sampling rate to be used
       with the	device.

       By default most OSS drivers will	attach virtual mixer  to  the  primary
       audio device of the sound card (or motherboard audio chip) when the de-
       vice is attached.  However possible secondary audio  devices  (engines)
       will  not have vmix attached by default.	In additional professional au-
       dio devices will	be attached without vmix because mixing	may cause some
       unwanted	distortion to the signal.

ATTACHING VMIX TO AN AUDIO DEVICE
       There are two forms of vmixctl attach command:

       o      vmixctl  attach audiodev This alternative	is to be used with de-
	      vices that support only output or	have  a	 single	 audio	device
	      file that	supports full duplex.

       o      vmixctl  attach  audiodev	inputdev The second form is to be used
	      with devices that	have separate output and input	device	files.
	      The  "audiodev" parameter	defines	the output device and the "in-
	      putdev" parameter	is the device file to be used for input	direc-
	      tion.   Note  that  both	device	files  must belong to the same
	      "physical" sound card.  In some cases it might  be  possible  to
	      use  one sound card for playback and another for recording. How-
	      ever this	configuration is not supported and the result may  not
	      be functional.

       To find out the right device file names (audiodev and inputdev) you can
       use the "ossinfo	-a" command.

   ATTACH OPTIONS
       o      -r      Disable recording	functionality. By  default  vmix  will
	      support recording	if the master device(s)	support	it.

       o      -p       Do not preallocate client engines. By default vmix will
	      preallocate first	4 (out of 8) client engines when attaching  to
	      the device. The remaining	engines	will be	allocated on-demand if
	      there are	more concurrent	applications that use the device.

       o      -M      Make vmix	use more fragments.

       o      -V      Make client devices visible (have	private	 device	 nodes
	      under /dev).

       o      -c  <n>  Preallocate <n> client engines instead of 4. However -p
	      option makes this	option ineffective.

   EXAMPLES
       o      vmixctl attach /dev/oss/oss_envy240/pcm0

       o      vmixctl		  attach	     /dev/oss/oss_envy240/pcm0
	      /dev/oss/oss_envy240/pcmin0

SETTING	THE SAMPLING RATE USED BY VMIX
       The virtual mixer subsystem will	set the	physical audio devce(s)	to use
       fixed sampling rate that	is 48000 Hz by default.	It is possible to  use
       "vmixctl	 rate audiodev"	to switch vmix to use some different rate with
       this device (pair). You should use "ossinfo -a -v2" to verify that  the
       sampling	rate is	actually supported by the device. Otherwise the	actual
       device may enforce vmix to use the nearest supported rate (or some  de-
       fault rate).

       The  "audiodev" parameter is the	device file name (see ossinfo -a) that
       is used for playback. The input device name doesn't need	to  be	speci-
       fied.

       Note  that  some	 professional  audio devices may be locked to external
       sampling	rate or	some fixed rate	(defined in ossmix/ossxmis).  In  such
       case the	rate is	not changeable by vmixctl.

   EXAMPLE
       o      vmixctl rate /dev/oss/oss_envy240/pcm0 44100

CHANGING THE VMIX CHANNEL MAP
       The  vmix  subsystem  can  remap	channels, so that all output sent to a
       channel via vmix	will end up being played on a different	 channel.  The
       syntax  uses  a	list  of  channels, where typically 0=default, 1=left,
       2=right,	3=center, 4=lfe, 5=left	 surround,  6=right  surround,	7=left
       rear  and 8=right rear.	Note that vmix-channels	should be set first to
       Multich if vmix is to recognize the extra channels.

   EXAMPLES
       o      vmixctl remap /dev/dsp 2 1 #switch left and right

       o      vmixctl remap /dev/dsp 0 0 0 0 6 5 #switch left and  right  sur-
	      round

DETACHING VMIX FROM AN AUDIO DEVICE
       It  is  possible	to detach vmix from an audio device if it causes prob-
       lems with applications by using "vmix detach audiodev".

       It is not possible to detach and	(re)attach vmix	 to  the  same	device
       more  than  few times. Use the vmix-enable setting in the control panel
       (ossxmix	or ossmix) to disable/re-enable	vmix if	you need to do it  re-
       peatedly.  Use vmix detach only if you need to attach virtual mixer us-
       ing different parameters.

   EXAMPLE
       o      vmix detach /dev/oss/oss_envy240/pcm0

POSSIBLE BUGS
       o      The control panel	elements related with  vmix  are  not  removed
	      from  the	 mixer	API when vmix is detached. This	may be somehow
	      confusing.

SEE ALSO
       soundoff(1), soundon(1),	ossmix(1), ossxmix(1)

FILES
       /usr/local/sbin/vmixct

AUTHOR
       4Front Technologies

				 08 July 2017			    vmixctl(8)

NAME | SYNOPSIS | DESCRIPTION | ATTACHING VMIX TO AN AUDIO DEVICE | SETTING THE SAMPLING RATE USED BY VMIX | CHANGING THE VMIX CHANNEL MAP | DETACHING VMIX FROM AN AUDIO DEVICE | POSSIBLE BUGS | SEE ALSO | FILES | AUTHOR

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=vmixctl&sektion=8&manpath=FreeBSD+12.1-RELEASE+and+Ports>

home | help