NetBSD/share/man/man4/uaudio.4

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.Dd July 12, 1998
.Dt UAUDIO 4
.Os
.Sh NAME
.Nm uaudio
.Nd USB audio device driver
.Sh SYNOPSIS
.Cd "uaudio* at uhub?"
.Cd "audio*  at uaudio?"
.Pp
.Sh DESCRIPTION
The
.Nm
driver provides support for 
.Tn USB
audio class devices.
.Pp
A 
.Tn 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
.Nm
driver and are accessible via the mixer (see
.Xr audio 4 )
interface:
.Bl -tag -width -offset 3n -compact
.It 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
.Ar mixN-S ,
where 
.Ar N
is a number that identifies which mixer it is and
.Ar S
which input.
.It selector
Not implemented yet.
.It feature
A feature unit changes the sound in some way, like bass, treble, or
volume.
The name of the control is
.Ar feaN-S-F ,
where 
.Ar N
is a number that identifies which feature unit it is,
.Ar S
which input, and
.Ar F
which feature is affected.
.It 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
.Ar proN.M-enable ,
where 
.Ar N
is a number that identifies which processing unit it is and
.Ar M
which kind.
Depending on the type of processing unit there may be other controls
as well.
.It extension
An extension unit performs some unspecified audio processing
The name of the on-off control is
.Ar extN-enable ,
where 
.Ar N
is a number that identifies which processing unit it is.
.El
.Pp
For more information the
.Tn USB
Audio class specification is indispensable
reading.
.Sh BUGS
The mixer interface is really incomplete.
.Pp
There should be some heuristics that allows important controls,
e.g., volume, to be identified and given its traditional name.
.Sh SEE ALSO
The 
.Tn USB 
specifications can be found at
.Dv http://www.usb.org/developers/docs.htm .
.Pp
.Xr audio 4 ,
.Xr usb 4
.Sh HISTORY
The
.Nm
driver
appeared in
.Nx 1.5 .