12 The audio device serves a one-level directory,
13 giving access to the stereo audio ports.
15 is the data file, which can be written for audio playback.
16 Audio data is a sequence of stereo samples, left sample first.
17 Each sample is a 16 bit little-endian two's complement integer;
18 the default sampling rate is 44.1 kHz.
24 represents the number of bytes buffered for input or output.
27 is the control file associated with the audio port.
28 Each input and output source has an associated stereo volume control,
29 ranging from 0 (quiet) to 100 (loud).
30 In addition, there are controls for the sampling rate of the D/A and A/D converters
31 latency control and for any tone controls.
33 return lines of the form
45 possibly abbreviated if the values are shared or non-existent.
46 For example, if all of the values are shared, the form degenerates to
49 Valid sources depend on the particular audio device,
50 though all devices have an
52 stereo source, which controls the output volume from the D/A converter
56 Writes accept the same format with same abbreviations.
58 .B /sys/src/9/port/devaudio.c