dsp - Open Sound System audio devices
/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
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.
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
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.
See the Audio Programming section of the OSS Programmer's Guide
(DSP(2)) for more info.
Default audio device
Default audio device for applications using mmap(2)
Default audio device for applications sending Dolby Digital
(AC3) audio to an external receiver.
Default multichannel (4.0-7.1) audio output device
Default digital audio (S/PDIF) output device
Direct access device files for individual audio devices.
o /dev/dsp0 to /dev/dspN
Legacy style direct access audio device files.