oss_madi(7) [debian man page]
oss_madi(7) OSS Devices oss_madi(7) NAME
oss_madi - RME HDSP MADI and AES32 audio driver DESCRIPTION
Open Sound System driver for RME HDSP MADI and AES32 audio interfaces. This driver has been developed for RME HDSP MADI but it also supports HDSP AES32. The driver has been tested under Linux and Solaris under x86 and Sparc. The internal engine of the card supports 64 playback channels and 64 recording channels. Only the first channels are connected to the actual input and output ports of the card. The mixer section of the card has recording level settings for all inputs. There is also an output mixer. Each output channel has mixer sliders for corresponding input channel and corresponding audio playback channel. There is a full 64x(64+64) mixing matrix supported by the hardware. For the time being this mixer matrix cannot be accessed directly by the applications. However support for the SNDCTL_MIX_MATRIX_WRITE and SNDCTL_MIX_MATRIX_READ ioctl calls can be added in the future. DEVICE FILES
By default the driver will create input and output device files for each 32 stereo pairs. This can be changed by editing the settings in oss_madi.conf (see below). The application can set the devices to use 1, 2, 4, 8, 16, 32 or 64 channels. The device file being used selects the first channel slot within the available channels. For example pcm0 and pcmin0 sill select channel 0. Equally well pcm1 and pcmin1 will select channel slot 2 (assuming that madi_devsize option is set to 2). The first device (pcm0 and pcmin0) can be set to use up to 64 channels. The last devices (pcm31 and pcmin31) only support 1 or 2 channel mode. The other device files support channel configurations where the last channel doesn't exceed the number of total channels (madi_maxchannels). Also the driver will not let two device files to share any of the channels with some other open device file. This channel allocation mechanism gives maximum flexibility to the user. It is possible to use some output channels by multi channel appli- cation while the others are available for other applications. This works as long the channel allocations by different applications don't overlap. OPTIONS
o madi_maxchannels Number of channels supported by the driver. The default is 64 which is also the maximum. This parameter can be set to a lower value if full 64 channels are not required. With less channels the mixer/control panel interface will require less space on screen. o madi_devsize By default this parameter is set to 2 which means that a device file will be created for each stereo channel pair. Possible values are 1, 2, 4, 8, 16, 32 or 64. LIMITATIONS
o The current driver doesn't support all control panel features of the card. For example sampling rate is fixed to 48 kHz. More features will be added on contract. o Use of mmap() is and will not be supported. o Virtual mixer is not supported (yet). FILES
/etc/oss4/conf/oss_madi.conf Device configuration file. AUTHOR
4Front Technologies 16 December 2012 oss_madi(7)
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vmixctl(8) OSS 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 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 spec- ified. 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 confus- ing. SEE ALSO
soundoff(1), soundon(1), ossmix(1), ossxmix(1) FILES
/usr/sbin/vmixct AUTHOR
4Front Technologies 16 December 2012 vmixctl(8)