AUDIO(1)                                                 AUDIO(1)

     NAME
          mp3dec, mp3enc, oggdec, oggenc, flacdec, sundec, wavdec,
          pcmconv, mixfs - decode and encode audio files

     SYNOPSIS
          audio/mp3dec [ -d ]
          audio/oggdec
          audio/flacdec
          audio/wavdec
          audio/sundec

          audio/oggenc
          audio/mp3enc [ -hprv ] [ -b bitrate ] [ -B bitrate ] [ -m
          mode ] [ -q q ] [ -s sfreq ] [ -V q ] [ long or silly
          options ]

          audio/pcmconv [ -i fmt ] [ -o fmt ] [ -l length ]

          audio/mixfs [ -D ] [ -s srvname ] [ -m mtpt ]

     DESCRIPTION
          These programs decode and encode various audio formats from
          and to 16-bit stereo PCM (little endian). The decoders read
          the compressed audio data from standard input and produce
          PCM on standard output at a sampling frequency of 44.1KHz.

          Mp3dec decodes MPEG audio (layer 1, 2 and 3). The -d option
          enables debug output to standard error.  Oggdec, flacdec,
          sunwdec and wavdec are like mp3dec but decode OGG Vorbis,
          FLAC lossless audio, Sun audio and RIFF wave.

          The encoders read PCM on standard input and produce com-
          pressed audio on standard output.

          Oggenc and mp3enc produce OGG Vorbis and MP3 audio. For
          mp3enc, the MP3 file will use `constant bit-rate' (CBR)
          encoding by default, but that can be changed via --abr
          (average bitrate desired, ABR) or -v (variable bitrate,
          VBR).

          Oggenc accepts raw PCM in the same byte order as /dev/audio
          (little-endian), t mp3enc -r expects big-endian.

        Options
          -b   set minimum allowed bitrate in Kb/s for VBR, default
               32Kb/s.  For CBR, set the exact bitrate in Kb/s, which
               defaults to 128Kb/s.
          -B   set maximum allowed bitrate in Kb/s for VBR, default
               256Kb/s.
          -h   same as `-q 2'.

     AUDIO(1)                                                 AUDIO(1)

          -m   mode may be (s)tereo, (j)oint, (f)orce or (m)ono
               (default j).  force forces mid/side stereo on all
               frames.
          -p   add CRC error protection (adds an additional 16 bits
               per frame to the stream).  This seems to break play-
               back.
          -q   sets output quality to q (see -V).
          -r   input is raw pcm
          -s   set sampling frequency of input file (in KHz) to sfreq,
               default is 44.1.
          -v   use variable bitrate (VBR) encoding
          -V   set quality setting for VBR to q. Default q is 4; 0
               produces highest-quality and largest files, and 9 pro-
               duces lowest-quality and smallest files.

        Long options
          --abr bitrate      sets average bitrate desired in Kb/s,
                             instead of setting quality, and generates
                             ABR encoding.
          --resample sfreq   set sampling frequency of output file (in
                             KHz) to sfreq, default is input sfreq.
          --mp3input input   is an MP3 file

        Silly options
          -f        same as `-q 7'.  Such a deal.
          -o        mark as non-original (i.e. do not set the original
                    bit)
          -c        mark as copyright
          -k        disable sfb=21 cutoff
          -e emp    de-emphasis n/5/c (default n)
          -d        allow channels to have different blocktypes
          -t        disable Xing VBR informational tag
          -a        autoconvert from stereo to mono file for mono
                    encoding
          -x        force byte-swapping of input (see dd(1) instead)
          -S        don't print progress report, VBR histograms
          --athonly only use the ATH for masking
          --nohist  disable VBR histogram display
          --voice   experimental voice mode

          Pcmconv is a helper program used to convert various PCM sam-
          ple formats. The -i and -o options specify the input and
          output format fmt of the conversion.  Fmt is a concatenated
          string of the following parts:

          s#   sample format is little-endian signed integer where #
               specifies the number of bits

          u#   unsigned little-endian integer format

          S#   singed big-endian integer format

     AUDIO(1)                                                 AUDIO(1)

          U#   unsigned big-endian integer format

          f#   floating point format where # has to be 32 or 64 for
               single- or double-precision

          a8   8-bit a-law format

          µ8   8-bit µ-law format

          c#   specifies the number of channels

          r#   gives the samplerate in Hz

          The program reads samples from standard input converting the
          data and writes the result to standard output until it
          reached end of file or, if -l was given, a number of length
          bytes have been consumed from input.

          Mixfs is a fileserver serving a single audio file which
          allows simultaneous playback of audio streams. When run, it
          binds over /dev/audio and mixes the audio samples that are
          written to it.  A service name srvname can be given with the
          -s option which gets posted to /srv.  By default, mixfs
          mounts itself on /mnt/mix and then binds /mnt/mix/audio over
          /dev.  A alternative mountpoint mtpt can be specified with
          the -m option.  The -D option causes 9p debug messages to be
          written to file-descriptor 2.

     EXAMPLE
          Play back an `.mp3'

               audio/mp3dec <foo.mp3 >/dev/audio

          Encode a `.wav' file as highest-quality MP3.

               audio/mp3enc -q 0 -b 320 <foo.wav >foo.mp3

          Create a fixed 128Kb/s MP3 file from a `.wav' file.

               audio/mp3enc -h <foo.wav >foo.mp3

          Streaming from stereo 44.1KHz raw PCM data, encoding mono at
          16KHz (you may not need dd):

               dd -conv swab | audio/mp3enc -a -r -m m --resample 16 -b 24

     SOURCE
          /sys/src/cmd/audio

     SEE ALSO
          play(1), juke(7), playlistfs(7)
          http://www.underbit.com/products/mad/

     AUDIO(1)                                                 AUDIO(1)

          http://xiph.org/doc/
          http://flac.sourceforge.net/documentation.html

     HISTORY
          Pcmconv first appeared in 9front (December, 2012).  Mixfs
          first appeared in 9front (December, 2013).