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osscore(7) OSS Devices osscore(7) NAME osscore - Open Sound Sytem core audio framework. DESCRIPTION Open Sound System core audio support psudo driver. This driver imple- ments 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: http://manuals.opensound.com/ OPTIONS 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 ex- ample) 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 us- ing a fully OSS 4.0 compatible mixer program such as ossxmix. Default: 0 - recording source is common to both channels. o ac97_amplifier When set to 1 this option enables the speaker power amplifier feature of AC97 codec (if available). Some boards have this in- verted, so this feature can be disabled by setting this option to 0. Affects all AC97 based audio devices in the system. De- fault: -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. Applica- tions that don't tolerate this kind of conversions usually dis- able them by using features of the OSS API (SNDCTL_DSP_COOKED- MODE). If this option is set to 0 then the format conversions will be disabled for all applications and devices unless the ap- plication 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 de- pendent buffsize. This option mustn't be changed unless it's absolutely necessary. o max_intrate Set the maximum number of interrupts per second. A value of 0 means the number is unlimited. Default: 100 interrupts per sec- ond which equals to about 10 msec minimum latencies. o vmix_disabled The virtual mixer subsystem can be disabled by setting this con- figuration option to 1. Default: 0 - virtual mixer is enabled. o vmix_loopdevs Optionally the virtual mixer subsystem can create special loop- back 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 loop- back devices. Default: 0 - no loopback devices are created. This setting should be left to 0 unless there are specific rea- sons 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). De- fault: 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. FILES /usr/local/lib/oss/conf/osscore.conf Device configuration file AUTHOR 4Front Technologies 12 April 2025 osscore(7)
NAME | DESCRIPTION | OPTIONS | FILES | AUTHOR
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