audio – audio device
bind -a #A /dev
unhandled troff command .sp
The audio device serves a one-level directory,
giving access to the stereo audio ports.
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.
The length of the
file as returned by
represents the number of bytes buffered for output.
is driver specific control file and left undocumented here.
is a read only status file. The first line has a length of 32 bytes
including the newline and starts with the string
followed by the preferred write unit (in bytes) and the string
followed by the number of bytes currently queued for output. The
numbers are decimal and right-padded with spaces to fit.
After this fixed header, the contents of the file is driver specific.
is the control file associated with the audio port. Each source has
an associated stereo volume control,
ranging from 0 (quiet) to 100 (loud).
In addition, there are controls for the sampling rate,
latency control and for any tone controls.
return lines of the form
Valid sources depend on the particular audio device,
though all devices have an
stereo source, which controls the output volume from the D/A converter.
set the sampling frequency of the audio device and
limits the audio data output buffering to a number of samples.
Writes accept the same format except that for stereo sources
can be abbreviated to a single
if both should be set the same.