.TH AUDIO 3 
.SH NAME
audio \- audio device
.SH SYNOPSIS
.nf
.B bind -a #A /dev
.sp 0.3v
.B /dev/audio
.B /dev/volume
.fi
.SH DESCRIPTION
The audio device serves a one-level directory,
giving access to the stereo audio ports.
.B Audio
is the data file, which can be written for audio playback.
Audio data is a sequence of stereo samples, left sample first.
Each sample is a 16 bit little-endian two's complement integer;
the default sampling rate is 44.1 kHz.
.PP
The length of the
.B audio
file as returned by
.IR stat (2)
represents the number of bytes buffered for input or output.
.PP
.B Volume
is the control file associated with the audio port.
Each input and output source has an associated stereo volume control,
ranging from 0 (quiet) to 100 (loud).
In addition, there are controls for the sampling rate of the D/A and A/D converters
latency control and for any tone controls.
Reads
return lines of the form
.IP
.I source
.B in left
.I value 
.B right
.I value
.B out left
.I value
.B right
.I value
.PP
possibly abbreviated if the values are shared or non-existent.
For example, if all of the values are shared, the form degenerates to
.RI ` source
.IR value '.
Valid sources depend on the particular audio device,
though all devices have an
.B audio
stereo source, which controls the output volume from the D/A converter
connected to
.BR audio .
.PP
Writes accept the same format with same abbreviations.
.SH SOURCE
.B /sys/src/9/port/devaudio.c
.SH SEE ALSO
.IR nusb (4)