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uaudio(4) [netbsd man page]

UAUDIO(4)						   BSD Kernel Interfaces Manual 						 UAUDIO(4)

NAME
uaudio -- USB audio device driver SYNOPSIS
uaudio* at uhub? audio* at audiobus? DESCRIPTION
The uaudio driver provides support for USB audio class devices. A USB audio device consists of a number of components: input terminals (e.g. USB digital input), output terminals (e.g. speakers), and a number of units in between (e.g. volume control). The following types of units are handled by the uaudio driver and are accessible via the mixer (see audio(4)) interface: mixer A mixer has a number of inputs and one output. Each input has a control that determines its volume in the output. The name of the control is mixN-S, where N is a number that identifies which mixer it is and S which input. selector A selector unit selects one of multiple audio sources such as mic-in and line-in. The name of the control is selN-S1S2S3..., where N is a number that identifies which selector unit it is and the sequence of Sn indicates candidate units for the audio source. feature A feature unit changes the sound in some way, like bass, treble, mute, or volume. The name of the control is determined in a heuristic way. If the unit changes the sound to a speaker output terminal, the names of the controls may be out- puts.speaker.bass, outputs.speaker.treble, outputs.speaker.mute, outputs.speaker, or likewise. processing A processing unit does one of a number of audio processing functions (e.g., channel up-down mixing, Dolby ProLogic, or cho- rus effects). The name of the on-off control is proN.M-enable, where N is a number that identifies which processing unit it is and M which kind. Depending on the type of processing unit there may be other controls as well. extension An extension unit performs some unspecified audio processing The name of the on-off control is extN-enable, where N is a number that identifies which processing unit it is. For more information the USB Audio class specification is indispensable reading. SEE ALSO
audio(4), usb(4) USB Approved Class Specification Documents, http://www.usb.org/developers/devclass_docs/. HISTORY
The uaudio driver appeared in NetBSD 1.5. BUGS
There is no support for multiple-endpoints audio stream, adaptive recording, async playback, and TYPE-II/III formats. There is the possibility that a device has multiple mixer items which have the same name. BSD
September 20, 2011 BSD

Check Out this Related Man Page

oss_usb(7)							    OSS Devices 							oss_usb(7)

NAME
oss_usb - USB Audio/MIDI/Mixer driver DESCRIPTION
The Open Sound System driver for USB Audio and MIDI devices. AUDIO The Audio driver supports: o 8-96Khz Playback/Recording o 8 or 16 or 32 bits o 2, 4, 6 or 8 channel audio. o SPDIF digital output and Input o AC3 passthrough o Volume control and device input mixer MIDI The oss_usb driver supports all MIDI devices that are compatible with the official USB MIDI specification. In addition the driver supports few devices that use their own private protocol (including some Yamaha and Midiman models). USB MIXER The USB Audio mixer is a new type of mixer that doesn't have the normal volume controls found on AC97 or Legacy SB devices. The USB audio mixer provides control for selecting the Alternate device setting - this usually allows the device to be switched into a Professional audio mode (eg 24bit or 96Khz mode) ALTERNATIVE SETTINGS Some USB audio devices use a feature called as alternative settings for bandwidth management. Typically such devices have multiple high speed inputs and outputs that may require more bandwidth than provided by the USB bus. The alternative settings feature is used to select between multiple low speed devices or just few high speed devices. When the device has multiple alternative settings an "altsetting" selector will be visible in the control panel for the device (use oss- mix(1) or ossxmix(1) to change it). Alternative setting OFF means that all audio devices are disabled. The other settings provide different combinations of high/medium speed devices. You can use the ossinfo(1) command (ossinfo -a -v3) to find out the devices supported by the currently selected alternative settings and the capabilities of them. KNOWN BUGS
Under Linux it is necessary to run the ossdetect -d and ossdevlinks commands after an USB device has been hot-plugged. Alternatively you can execute soundoff and soundon to reload OSS. OPTIONS
None FILES
/etc/oss4/conf/oss_usb.conf Device configuration file AUTHOR
4Front Technologies 16 December 2012 oss_usb(7)
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