AUDIO(3)                                                 AUDIO(3)

     NAME
          audio - 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-independent 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 sample 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 volume 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
               channels.  Format is one of ulaw, alaw, pcm, pcm16 or
               adpcm

     AUDIO(3)                                                 AUDIO(3)

          loop value
               Value is 0 or 1 to disable or enable loopback respec-
               tively.

          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 ALSO
          auplay(1)
          audio(6)

     BUGS
          The device has not been implemented on every platform that
          could provide it, particularly hosted implementations.
          /os/port/devaudio.c (a driver for the SB16) implements an
          older interface of broadly similar form, but using volume
          not audioctl, and supports a subset of the commands
          described above.
          The device is exclusive-use and cannot mix streams from sev-
          eral clients.