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UAUDIO(4)                    Device Drivers 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 outputs.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
                 chorus 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/docs/devclass_docs/.

HISTORY
     The uaudio driver appeared in NetBSD 1.5.  Support for USB Audio Class
     2.0 devices appeared in NetBSD 11.0.

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.

NetBSD 11.99                     May 21, 2024                     NetBSD 11.99