| | Open Sound System |
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unsigned int (*adrv_set_channels) (int dev, unsigned int nch);
The first paramater (dev) is anways the audio engine number which is an index to the audio_engines table. The driver can use the audio_engines entry to find out some of the current parameters. In particular the devc, portc, portc_play and portc_record fields can be used to locate the driver defined structures for the audio engine.
The purpose of this audio driver method is very simple. It sets the number of channels to be used when the adrv_prepare_for_input and adrv_prepare_for_output methods get called to start the device. The change in the number of channels in no case take effect immediately. Instead the driver should store the new format in the portc structure for the engine until the adrv_prepare_for_* method gets called.
Audio driver entry point should return 0 if the call was successful. Negative return value (-errno) means that an error has occurred. However some of the functions have void type and they don't return any value.
| vmix_core/vmix_input.c | Virtual mixing audio driver recording routines |
| vmix_core/vmix_output.c | Virtual mixing audio driver output mixing routines |
| audio/oss_audio_core.c | Audio core functionality of OSS |
| include/ossddk.h | Source file oss-current/kernel/framework/include/ossddk/ossddk.h |
| remux/oss_remux.c | Multi channel playback support for devices with multiple stereo engines. |