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osscore(7)			  OSS Devices			    osscore(7)

       osscore - Open Sound Sytem core audio framework.

       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:

       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

       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  pro-
	      cesses,  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.

       /usr/local/lib/oss/conf/osscore.conf Device configuration file

       4Front Technologies

				 08 July 2017			    osscore(7)


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