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diff --git a/cmd/vmixctl/vmixctl.man b/cmd/vmixctl/vmixctl.man new file mode 100644 index 0000000..c7ac50e --- /dev/null +++ b/cmd/vmixctl/vmixctl.man @@ -0,0 +1,111 @@ +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 device is attached. +However possible secondary audio devices (engines) will not have vmix +attached by default. In additional professional audio 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 devices 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 "inputdev" parameter is the device file to be used for input direction. +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. However 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 default 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 specified. + +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 surround + +DETACHING VMIX FROM AN AUDIO DEVICE +It is possible to detach vmix from an audio device if it causes problems +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 +repeatedly. Use vmix detach only if you need to attach virtual mixer using +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/sbin/vmixct + +AUTHOR +4Front Technologies |