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NAME
dsp - Open Sound System audio devices
DESCRIPTION
/dev/dsp is the default audio device in the system. It's connected to the
main speakers and the primary recording source (such as microphone). The system
administrator can set /dev/dsp to be a symbolic link to the desired default
device. The ossinfo utility can be used to list the available audio devices
in the system.
/dev/dsp_mmap, /dev/dsp_ac3, /dev/dsp_multich and /dev/dsp_spdifout are
default audio devices for specific applications such as games or media (DVD)
players.
DIRECT ACCESS AUDIO DEVICE FILES
OSS 4.0 (and later) will create audio devices under /dev/oss/<device> directory.
For example /dev/oss/sblive0/pcm0 is the first audio device that belongs to the
first Sound Blaster Live! or Audigy card in the system. These direct devices
are used when an application needs to access specific audio device (instead of
the default one).
You can use the ossinfo(1) utility with the -a option to get a list of the
available audio devices in the system.
LEGACY AUDIO DEVICE FILES
Traditionally OSS has created device files like /dev/dsp0 to /dev/dspN for
each audio device in the system. OSS 4.0 still supports this legacy naming.
These files are symbolic links to the actual device files located under
/dev/oss. The ossdevlinks(8) utility is used to manage these links and it
will be automatically invoked when OSS is started.
COMPATIBILITY
o The /dev/dsp (default() audio device file will be supported by all OSS
implementations and versions.
o The special purpose audio default devices (such as /dev/dsp_mmap) are only
supported by OSS 4.0 and later.
o The legacy audio device files (such as /dev/dsp1) are supported by all OSS
versions and implementations.
o New style audio device files (under /dev/oss) are only supported by OSS 4.0
and later. However some independent OSS implementations may only support
the legacy naming even they are otherwise OSS 4.0 compatible.
o /dev/dsp0 doesn't exist in all Linux systems which use /dev/dsp for the same
purpose. In such systems /dev/dsp points to the first audio device and
/dev/dsp1 to the second.
PROGRAMMING INFORMATION
See the Audio Programming section of the OSS Programmer's Guide (DSP(2)) for
more info.
OPTIONS
None
FILES
o /dev/dsp Default audio device
o /dev/dsp_mmap Default audio device for applications using mmap(2)
o /dev/dsp_ac3 Default audio device for applications sending Dolby
Digital (AC3) audio to an external receiver.
o /dev/dsp_multich Default multichannel (4.0-7.1) audio output device
o /dev/dsp_spdifout Default digital audio (S/PDIF) output device
o /dev/oss/<driver>/pcmN Direct access device files for individual audio
devices.
o /dev/dsp0 to /dev/dspN Legacy style direct access audio device files.
AUTHOR
4Front Technologies
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