osscore - Open Sound Sytem core audio framework.
Open Sound System core audio support psudo driver. This driver
implements the core Open Sound System API for audio, midi, mixer and
synth functions. This driver also implements the OS driver interface as
well as device configuration and setup. More information on
programming on the OSS API is avaialable at:
When set to 1 this option enables independent recording source
selection for the left and the right channel on AC97 devices. In
this way it's possible to record audio streams so that (for
example) the left channel signal comes from the microphone and
the right channel signal from line-in. However when this option
is enabled it's only possible to select the recording source by
using a fully OSS 4.0 compatible mixer program such as ossxmix.
Default: 0 - recording source is common to both channels.
When set to 1 this option enables the speaker power amplifier
feature of AC97 codec (if available). Some boards have this
inverted, so this feature can be disabled by setting this option
to 0. Affects all AC97 based audio devices in the system.
Default: -1=autodetect correct setting.
By default OSS will let applications to use sampling rates and
formats that are not supported by the hardware. Instead OSS
performs the necessary format conversions in software.
Applications that don't tolerate this kind of conversions
usually disable them by using features of the OSS API
(SNDCTL_DSP_COOKEDMODE). If this option is set to 0 then the
format conversions will be disabled for all applications and
devices unless the application explicitly enables them.
Default: 1 - conversions are enabled. This option should not be
changed without very strong reasons.
Internal debugging (do not change). Default: 0
By default OSS will allocate audio DMA buffers with some system
dependent default size (usually 64k but sometimes smaller). It
is possible to change this default allocation by setting this
option. Value of 0 means that the default size will be used.
Value between 16 and 128 (kilobytes) can be used if the default
size is not suitable for some reason. Default: 0 - system
dependent buffsize. This option mustn't be changed unless it's
Set the maximum number of interrupts per second. Default: 100
interrupts per second which equals to about 10 msec minimum
The virtual mixer subsystem can be disabled by setting this
configuration option to 1. Default: 0 - virtual mixer is
Optionally the virtual mixer subsystem can create special
loopback audio devices that can be used to record the output mix
sent to the device. This option tells how many loopback devices
will be created (0, 1 or 2). If there are multiple audio devices
in the system the all of them will have the same number of
loopback devices. Default: 0 - no loopback devices are created.
This setting should be left to 0 unless there are specific
reasons to enable the loopback devices.
By default (0) the low level drivers for most sound cards will
automatically attach virtual mixer (vmix) to the primary audio
devices of the cards. In some situations it may be necessary to
attach virtual mixer using nonstandard parameters. If
vmix_no_autoattach is set to 1 then user can use vmixctl attach
command to attach virtual mixer manually to the device(s).
Default: 0 - Automatically attach virtual mixer.
The O_EXCL open() flag can be used by programs to bypass the
virtual mixer. Setting excl_policy to 1 or 2 makes OSS ignore
O_EXCL. A setting of 1 ignores O_EXCL from all but root
processes, while a setting of 2 always ignores O_EXCL. Default:
0 - Do not ignore O_EXCL.
By default OSS will set most volume controls to audible level.
If this causes problems then it's possible to ask OSS to set the
levels to zero when the drivers are loaded. However the levels
saved with the savemixer utility will get loaded few moments
later when all OSS drivers have been started. Note that just
some of the OSS drivers honor this setting. Values: 0 (default)
- Use audible volumes, 1 - Set volumes to low.
/usr/lib/oss/conf/osscore.conf Device configuration file
31 July 2010 osscore(7)