uaudio(4) - NetBSD Manual Pages

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UAUDIO(4)               NetBSD Kernel Interfaces Manual              UAUDIO(4)


NAME

     uaudio - USB audio device driver


SYNOPSIS

     uaudio* at uhub?
     audio*  at uaudio?


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      Not implemented yet.
        feature       A feature unit changes the sound in some way, like bass,
                      treble, or volume.  The name of the control is feaN-S-F,
                      where N is a number that identifies which feature unit
                      it is, S which input, and F which feature is affected.
        processing    A processing unit does one of a number of audio process-
                      ing functions (e.g., channel up-down mixing, Dolby Pro-
                      Logic, or chorus effects).  The name of the on-off con-
                      trol is proN.M-enable, where N is a number that identi-
                      fies 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 pro-
                      cessing 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

     The USB specifications can be found at:
     http://www.usb.org/developers/docs.html

     audio(4), usb(4)


HISTORY

     The uaudio driver appeared in NetBSD 1.5.


BUGS

     The mixer interface is really incomplete.

     There should be some heuristics that allows important controls, e.g.,
     volume, to be identified and given its traditional name.

NetBSD 2.1                       July 12, 1998                      NetBSD 2.1