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:
/usr/local/lib/oss/conf/osscore.conf Device configuration file
- o ac97_recselect
- 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
- o ac97_amplifier
- 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.
- o cooked_enable
- 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.
- o detect_trace
- Internal debugging (do not change). Default: 0
- o dma_buffsize
- 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
- o max_intrate
- Set the maximum number of interrupts per second. A value of 0 means the
number is unlimited. Default: 100 interrupts per second which equals to
about 10 msec minimum latencies.
- o vmix_disabled
- The virtual mixer subsystem can be disabled by setting this configuration
option to 1. Default: 0 - virtual mixer is enabled.
- o vmix_loopdevs
- 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.
- o vmix_no_autoattach
- 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.
- o excl_policy
- 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.
- o mixer_muted
- 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.
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