AUDIO(3)AUDIO(3)NAMEaudio - digital audio input and output
SYNOPSIS
bind -a '#A' /dev
/dev/audio
/dev/audioctl
DESCRIPTION
The audio device serves a one-level directory containing two files,
giving access to the host or native audio device in a platform-indepen‐
dent way.
Audio is the data file, which can be read or written to exchange data
with the device. Audio data is a sequence of stereo samples, left sam‐
ple first, each of which is a 16 bit little-endian two's complement
integer.
Audioctl is the associated control file, which sets the characteristics
of the device. Reads return lines of the form
source [in out] value
source in value out value
source [in out] left value right value
source in left value right value out left value right value
The qualifiers in, out and left, right are omitted if they are
not applicable or if the input/output and/or left/right values
are the same. The source is one of audio, aux1, aux2, line,
mono, mic, rate, chans or bits. If source is one of the ports
audio, aux1, aux2, line, mono or mic, value represents the vol‐
ume on a scale of 0 (quiet) to 100 (loud). The default volume is
50 for the audio port and 0 for the remainder. If the source is
rate, value represents the rate at which the data was recorded
in Hz. The default is 22050. If the source is chans, value is
the number of channels of audio data - 2 (the default) for
stereo, otherwise mono. If the source is bits, value is one of
4, 8 or 16, the sample size in bits.
[in out] enc format
Outputs the recording format on the input and/or output chan‐
nels. Format is one of ulaw, alaw, pcm, pcm16 or adpcm
loop value
Value is 0 or 1 to disable or enable loopback respectively.
Writes control the device with strings of a similar format as that for
reads.
source [in out] value
source in value out value
source [in out] left value right value
source in left value right value out left value right value
Set the corresponding value/volume for the particular source.
The same conventions apply as in the read case above. The
default value of source is audio.
reset Set all attributes to their default value.
loop value
Enable (1) or disable (0) loopback mode.
[in out] enc format
Set the recording format on the input and/or output channels to
format. Format is one of ulaw, alaw, pcm, adpcm.
[left right] dev input
Set the input source of the left and/or right ADCs. Input is
one of mic, line, aux1, loop.
SOURCE
/emu/port/devaudio*.c
/emu/*/devaudio.c
/os/*/devaudio.c
/os/*/devcs4231.c
SEE ALSOauplay(1)audio(6)BUGS
The device has not been implemented on every platform that could pro‐
vide it, particularly hosted implementations.
/os/port/devaudio.c (a driver for the SB16) implements an older inter‐
face of broadly similar form, but using volume not audioctl, and sup‐
ports a subset of the commands described above.
The device is exclusive-use and cannot mix streams from several
clients.
AUDIO(3)
