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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



 NAME
      mpg123 - play audio MPEG 1.0/2.0/2.5 stream (layers 1, 2 and 3)

 SYNOPSIS
      mpg123 [ options ] file-or-URL...

 DESCRIPTION
      mpg123 reads one or more files (or standard input if ``-'' is
      specified) or URLs and plays them on the audio device (default) or
      outputs them to stdout.  file/URL is assumed to be an MPEG audio bit
      stream.

 OPERANDS
      The following operands are supported:

      file(s) The path name(s) of one or more input files.  They must be
              valid MPEG-1.0/2.0/2.5 audio layer 1, 2 or 3 bit streams.  If
              a dash ``-'' is specified, MPEG data will be read from the
              standard input.  Furthermore, any name starting with
              ``http://'' is recognized as URL (see next section).

 OPTIONS
      mpg123 options may be either the traditional POSIX one letter options,
      or the GNU style long options.  POSIX style options start with a
      single ``-'', while GNU long options start with ``--''.  Option
      arguments (if needed) follow separated by whitespace (not ``='').
      Note that some options can be absent from your installation when
      disabled in the build process.

 INPUT OPTIONS
      -k num, --skip num
           Skip first num frames.  By default the decoding starts at the
           first frame.

      -n num, --frames num
           Decode only num frames.  By default the complete stream is
           decoded.

      --fuzzy
           Enable fuzzy seeks (guessing byte offsets or using approximate
           seek points from Xing TOC).  Without that, seeks need a first
           scan through the file before they can jump at positions.  You can
           decide here: sample-accurate operation with gapless features or
           faster (fuzzy) seeking.

      -y, --no-resync
           Do NOT try to resync and continue decoding if an error occurs in
           the input file. Normally, mpg123 tries to keep the playback alive
           at all costs, including skipping invalid material and searching
           new header when something goes wrong.  With this switch you can
           make it bail out on data errors (and perhaps spare your ears a



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



           bad time). Note that this switch has been renamed from --resync.
           The old name still works, but is not advertised or recommened to
           use (subject to removal in future).

      --resync-limit bytes
           Set number of bytes to search for valid MPEG data once lost in
           stream; <0 means search whole stream.  If you know there are huge
           chunks of invalid data in your files... here is your hammer.
           Note: Only since version 1.14 this also increases the amount of
           junk skipped on beginning.

      -p URL | none, --proxy URL | none
           The specified proxy will be used for HTTP requests.  It should be
           specified as full URL (``http://host.domain:port/''), but the
           ``http://'' prefix, the port number and the trailing slash are
           optional (the default port is 80).  Specifying none means not to
           use any proxy, and to retrieve files directly from the respective
           servers.  See also the ``HTTP SUPPORT'' section.

      -u auth, --auth auth
           HTTP authentication to use when recieving files via HTTP.  The
           format used is user:password.

      --ignore-mime
           Ignore MIME types given by HTTP server. If you know better and
           want mpg123 to decode something the server thinks is image/png,
           then just do it.

      --no-seekbuffer
           Disable the default micro-buffering of non-seekable streams that
           gives the parser a safer footing.

      -@ file, --list file
           Read filenames and/or URLs of MPEG audio streams from the
           specified file in addition to the ones specified on the command
           line (if any).  Note that file can be either an ordinary file, a
           dash ``-'' to indicate that a list of filenames/URLs is to be
           read from the standard input, or an URL pointing to a an
           appropriate list file.  Note: only one -@ option can be used (if
           more than one is specified, only the last one will be
           recognized).

      -l n, --listentry n
           Of the playlist, play specified entry only. n is the number of
           entry starting at 1. A value of 0 is the default and means
           playling the whole list,  a negative value means showing of the
           list of titles with their numbers...

      --continue
           Enable playlist continuation mode. This changes frame skipping to
           apply only to the first track and also continues to play



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



           following tracks in playlist after the selected one. Also, the
           option to play a number of frames only applies to the whole
           playlist. Basically, this tries to treat the playlist more like
           one big stream (like, an audio book).  The current track number
           in list (1-based) and frame number (0-based) are printed at exit
           (useful if you interrupted playback and want to continue later).
           Note that the continuation info is printed to standard output
           unless the switch for piping audio data to standard out is used.
           Also, it really makes sense to work with actual playlist files
           instead of lists of file names as arguments, to keep track
           positions consistent.

      --loop times
           for looping track(s) a certain number of times, < 0 means
           infinite loop (not with --random!).

      --keep-open
           For remote control mode: Keep loaded file open after reaching
           end.

      --timeout seconds
           Timeout in (integer) seconds before declaring a stream dead (if
           <= 0, wait forever).

      -z, --shuffle
           Shuffle play.  Randomly shuffles the order of files specified on
           the command line, or in the list file.

      -Z, --random
           Continuous random play.  Keeps picking a random file from the
           command line or the play list.  Unlike shuffle play above, random
           play never ends, and plays individual songs more than once.

      --no-icy-meta
           Do not accept ICY meta data.

      -i, --index
           Index / scan through the track before playback.  This fills the
           index table for seeking (if enabled in libmpg123) and may make
           the operating system cache the file contents for smoother
           operating on playback.

      --index-size size
           Set the number of entries in the seek frame index table.

      --preframes num
           Set the number of frames to be read as lead-in before a seeked-to
           position.  This serves to fill the layer 3 bit reservoir, which
           is needed to faithfully reproduce a certain sample at a certain
           position.  Note that for layer 3, a minimum of 1 is enforced
           (because of frame overlap), and for layer 1 and 2, this is



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



           limited to 2 (no bit reservoir in that case, but engine spin-up
           anyway).


 OUTPUT and PROCESSING OPTIONS
      -o module, --output module
           Select audio output module. You can provide a comma-separated
           list to use the first one that works.

      --list-modules
           List the available modules.

      -a dev, --audiodevice dev
           Specify the audio device to use.  The default is system-dependent
           (usually /dev/audio or /dev/dsp).  Use this option if you have
           multiple audio devices and the default is not what you want.

      -s, --stdout
           The decoded audio samples are written to standard output, instead
           of playing them through the audio device.  This option must be
           used if your audio hardware is not supported by mpg123.  The
           output format per default is raw (headerless) linear PCM audio
           data, 16 bit, stereo, host byte order (you can force mono or
           8bit).

      -O file, --outfile
           Write raw output into a file (instead of simply redirecting
           standard output to a file with the shell).

      -w file, --wav
           Write output as WAV file. This will cause the MPEG stream to be
           decoded and saved as file file , or standard output if - is used
           as file name. You can also use --au and --cdr for AU and CDR
           format, respectively. Note that WAV/AU writing to non-seekable
           files, or redirected stdout, needs some thought. Since 1.16.0,
           the logic changed to writing the header with the first actual
           data. This avoids spurious WAV headers in a pipe, for example.
           The result of decoding nothing to WAV/AU is a file consisting
           just of the header when it is seekable and really nothing when
           not (not even a header). Correctly writing data with prophetic
           headers to stdout is no easy business.

      --au file
           Does not play the MPEG file but writes it to file in SUN audio
           format.  If - is used as the filename, the AU file is written to
           stdout. See paragraph about WAV writing for header fun with non-
           seekable streams.

      --cdr file
           Does not play the MPEG file but writes it to file as a CDR file.
           If - is used as the filename, the CDR file is written to stdout.



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      --reopen
           Forces reopen of the audiodevice after ever song

      --cpu decoder-type
           Selects a certain decoder (optimized for specific CPU), for
           example i586 or MMX.  The list of available decoders can vary;
           depending on the build and what your CPU supports.  This options
           is only availabe when the build actually includes several
           optimized decoders.

      --test-cpu
           Tests your CPU and prints a list of possible choices for --cpu.

      --list-cpu
           Lists all available decoder choices, regardless of support by
           your CPU.

      -g gain, --gain gain
           [DEPRECATED] Set audio hardware output gain (default: don't
           change). The unit of the gain value is hardware and output module
           dependent.  (This parameter is only provided for backwards
           compatibility and may be removed in the future without prior
           notice. Use the audio player for playing and a mixer app for
           mixing, UNIX style!)

      -f factor, --scale factor
           Change scale factor (default: 32768).

      --rva-mix, --rva-radio
           Enable RVA (relative volume adjustment) using the values stored
           for ReplayGain radio mode / mix mode with all tracks roughly
           equal loudness.  The first valid information found in ID3V2 Tags
           (Comment named RVA or the RVA2 frame) or ReplayGain header in
           Lame/Info Tag is used.

      --rva-album, --rva-audiophile
           Enable RVA (relative volume adjustment) using the values stored
           for ReplayGain audiophile mode / album mode with usually the
           effect of adjusting album loudness but keeping relative loudness
           inside album.  The first valid information found in ID3V2 Tags
           (Comment named RVA_ALBUM or the RVA2 frame) or ReplayGain header
           in Lame/Info Tag is used.

      -0, --single0; -1,
           Decode only channel 0 (left) or channel 1 (right), respectively.
           These options are available for stereo MPEG streams only.

      -m, --mono, --mix,
           Mix both channels / decode mono. It takes less CPU time than full
           stereo decoding.




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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      --stereo
           Force stereo output

      -r rate, --rate rate
           Set sample rate (default: automatic).  You may want to change
           this if you need a constant bitrate independent of the mpeg
           stream rate. mpg123 automagically converts the rate. You should
           then combine this with --stereo or --mono.

      -2, --2to1; -4,
           Performs a downsampling of ratio 2:1 (22 kHz) or 4:1 (11 kHz) on
           the output stream, respectively. Saves some CPU cycles, but at
           least the 4:1 ratio sounds ugly.

      --pitch value
           Set hardware pitch (speedup/down, 0 is neutral; 0.05 is 5%). This
           changes the output sampling rate, so it only works in the range
           your audio system/hardware supports.

      --8bit
           Forces 8bit output

      --float
           Forces f32 encoding

      -e enc, --encoding enc
           Choose output sample encoding. Possible values look like f32
           (32-bit floating point), s32 (32-bit signed integer), u32 (32-bit
           unsigned integer) and the variants with different numbers of bits
           (s24, u24, s16, u16, s8, u8) and also special variants like ulaw
           and alaw 8-bit.  See the output of mpg123's longhelp for actually
           available encodings.

      -d n, --doublespeed n
           Only play every n'th frame.  This will cause the MPEG stream to
           be played n times faster, which can be used for special effects.
           Can also be combined with the --halfspeed option to play 3 out of
           4 frames etc.  Don't expect great sound quality when using this
           option.

      -h n, --halfspeed n
           Play each frame n times.  This will cause the MPEG stream to be
           played at 1/n'th speed (n times slower), which can be used for
           special effects. Can also be combined with the --doublespeed
           option to double every third frame or things like that.  Don't
           expect great sound quality when using this option.

      -E file, --equalizer
           Enables equalization, taken from file.  The file needs to contain
           32 lines of data, additional comment lines may be prefixed with
           #.  Each data line consists of two floating-point entries,



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



           separated by whitespace.  They specify the multipliers for left
           and right channel of a certain frequency band, respectively.  The
           first line corresponds to the lowest, the 32nd to the highest
           frequency band.  Note that you can control the equalizer
           interactively with the generic control interface.

      --gapless
           Enable code that cuts (junk) samples at beginning and end of
           tracks, enabling gapless transitions between MPEG files when
           encoder padding and codec delays would prevent it.  This is
           enabled per default beginning with mpg123 version 1.0.0 .

      --no-gapless
           Disable the gapless code. That gives you MP3 decodings that
           include encoder delay and padding plus mpg123's decoder delay.

      --no-infoframe
           Do not parse the Xing/Lame/VBR/Info frame, decode it instead just
           like a stupid old MP3 hardware player.  This implies disabling of
           gapless playback as the necessary information is in said metadata
           frame.

      -D n, --delay n
           Insert a delay of n seconds before each track.

      -o h, --headphones
           Direct audio output to the headphone connector (some hardware
           only; AIX, HP, SUN).

      -o s, --speaker
           Direct audio output to the speaker  (some hardware only; AIX, HP,
           SUN).

      -o l, --lineout
           Direct audio output to the line-out connector (some hardware
           only; AIX, HP, SUN).

      -b size, --buffer size
           Use an audio output buffer of size Kbytes.  This is useful to
           bypass short periods of heavy system activity, which would
           normally cause the audio output to be interrupted. You should
           specify a buffer size of at least 1024 (i.e. 1 Mb, which equals
           about 6 seconds of audio data) or more; less than about 300 does
           not make much sense.  The default is 0, which turns buffering
           off.

      --preload fraction
           Wait for the buffer to be filled to fraction before starting
           playback (fraction between 0 and 1). You can tune this
           prebuffering to either get faster sound to your ears or safer
           uninterrupted web radio.  Default is 0.2 (wait for 20 % of buffer



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



           to be full, changed from 1 in version 1.23).

      --devbuffer seconds
           Set device buffer in seconds; <= 0 means default value. This is
           the small buffer between the application and the audio backend,
           possibly directly related to hardware buffers.

      --smooth
           Keep buffer over track boundaries -- meaning, do not empty the
           buffer between tracks for possibly some added smoothness.


 MISC OPTIONS
      -t, --test
           Test mode.  The audio stream is decoded, but no output occurs.

      -c, --check
           Check for filter range violations (clipping), and report them for
           each frame if any occur.

      -v, --verbose
           Increase the verbosity level.  For example, displays the frame
           numbers during decoding.

      -q, --quiet
           Quiet.  Suppress diagnostic messages.

      -C, --control
           Enable terminal control keys. This is enabled automatically if a
           terminal is detected.  By default use 's' or the space bar to
           stop/restart (pause, unpause) playback, 'f' to jump forward to
           the next song, 'b' to jump back to the beginning of the song, ','
           to rewind, '.' to fast forward, and 'q' to quit.  Type 'h' for a
           full list of available controls.

      --no-control
           Disable terminal control even if terminal is detected.

      --title
           In an xterm, rxvt, screen, iris-ansi (compatible, TERM
           environment variable is examined), change the window's title to
           the name of song currently playing.

      --name name
           Set the name of this instance, possibly used in various places.
           This sets the client name for JACK output.

      --long-tag
           Display ID3 tag info always in long format with one line per item
           (artist, title, ...)




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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      --utf8
           Regardless of environment, print metadata in UTF-8 (otherwise,
           when not using UTF-8 locale, you'll get ASCII stripdown).

      -R, --remote
           Activate generic control interface.  mpg123 will then read and
           execute commands from stdin. Basic usage is ``load <filename> ''
           to play some file and the obvious ``pause'', ``command.  ``jump
           <frame>'' will jump/seek to a given point (MPEG frame number).
           Issue ``help'' to get a full list of commands and syntax.

      --remote-err
           Print responses for generic control mode to standard error, not
           standard out.  This is automatically triggered when using -s N.

      --fifo path
           Create a fifo / named pipe on the given path and use that for
           reading commands instead of standard input.

      --aggressive
           Tries to get higher priority

      -T, --realtime
           Tries to gain realtime priority.  This option usually requires
           root privileges to have any effect.

      -?, --help
           Shows short usage instructions.

      --longhelp
           Shows long usage instructions.

      --version
           Print the version string.

 HTTP SUPPORT
      In addition to reading MPEG audio streams from ordinary files and from
      the standard input, mpg123 supports retrieval of MPEG audio files or
      playlists via the HTTP protocol, which is used in the World Wide Web
      (WWW).  Such files are specified using a so-called URL, which starts
      with ``http://''.  When a file with that prefix is encountered, mpg123
      attempts to open an HTTP connection to the server in order to retrieve
      that file to decode and play it.

      It is often useful to retrieve files through a WWW cache or so-called
      proxy.  To accomplish this, mpg123 examines the environment for
      variables named MP3_HTTP_PROXY, http_proxy and HTTP_PROXY, in this
      order.  The value of the first one that is set will be used as proxy
      specification.  To override this, you can use the -p command line
      option (see the ``OPTIONS'' section).  Specifying -p none will enforce
      contacting the server directly without using any proxy, even if one of



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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      the above environment variables is set.

      Note that, in order to play MPEG audio files from a WWW server, it is
      necessary that the connection to that server is fast enough.  For
      example, a 128 kbit/s MPEG file requires the network connection to be
      at least 128 kbit/s (16 kbyte/s) plus protocol overhead.  If you
      suffer from short network outages, you should try the -b option
      (buffer) to bypass such outages.  If your network connection is
      generally not fast enough to retrieve MPEG audio files in realtime,
      you can first download the files to your local harddisk (e.g. using
      wget(1)) and then play them from there.

      If authentication is needed to access the file it can be specified
      with the -u user:pass.

 INTERRUPT
      When in terminal control mode, you can quit via pressing the q key,
      while any time you can abort mpg123 by pressing Ctrl-C. If not in
      terminal control mode, this will skip to the next file (if any). If
      you want to abort playing immediately in that case, press Ctrl-C twice
      in short succession (within about one second).

      Note that the result of quitting mpg123 pressing Ctrl-C might not be
      audible immediately, due to audio data buffering in the audio device.
      This delay is system dependent, but it is usually not more than one or
      two seconds.


 PLAYBACK STATUS LINE
      In verbose mode, mpg123 updates a line with various information
      centering around the current playback position. On any decent
      terminal, the line also works as a progress bar in the current file by
      reversing video for a fraction of the line according to the current
      position. An example for a full line is this:

           > 0291+0955  00:01.68+00:28.22 [00:05.30] mix 100=085 192 kb/s
      576 B acc   18 clip p+0.014

      The information consists of, in order:

      >    single-character playback state (``>'' for playing, ``='' for
           pausing/looping, ``_'' for stopped)

      0291+0955
           current frame offset and number of remaining frames after the
           plus sign

      00:01.68+00:28.22
           current position from and remaining time in human terms (hours,
           minutes, seconds)




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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      [00:05.30]
           fill of the output buffer in terms of playback time, if the
           buffer is enabled

      mix  selected RVA mode (possible values: mix, alb (album), and ---
           (neutral, off))

      100=085
           set volume and the RVA-modified effective volume after the equal
           sign

      192 kb/s
           current bitrate

      576 B
           size of current frame in bytes

      acc  if positions are accurate, possible values are ``acc'' for
           accurate positions or ``fuz'' for fuzzy (with guessed byte
           offsets using mean frame size)

      18 clip
           amount of clipped samples, non-zero only if decoder reports that
           (generic does, some optimized ones not)

      p+0.014
           pitch change (increased/decreased playback sampling rate on user
           request)


 NOTES
      MPEG audio decoding requires a good deal of CPU performance,
      especially layer-3.  To decode it in realtime, you should have at
      least an i486DX4, Pentium, Alpha, SuperSparc or equivalent processor.
      You can also use the -m option to decode mono only, which reduces the
      CPU load somewhat for layer-3 streams.  See also the -2 and -4
      options.

      If everything else fails, have mpg123 decode to a file and then use an
      appropriate utility to play that file with less CPU load.  Most
      probably you can configure mpg123 to produce a format suitable for
      your audio device (see above about encodings and sampling rates).

      If your system is generally fast enough to decode in realtime, but
      there are sometimes periods of heavy system load (such as cronjobs,
      users logging in remotely, starting of ``big'' programs etc.) causing
      the audio output to be interrupted, then you should use the -b option
      to use a buffer of reasonable size (at least 1000 Kbytes).

 BUGS




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 mpg123(1)                                                         mpg123(1)
                                 29 Feb 2016



      Mostly MPEG-1 layer 2 and 3 are tested in real life.  Please report
      any issues and provide test files to help fixing them.

      No CRC error checking is performed.

      Some platforms lack audio hardware support; you may be able to use the
      -s switch to feed the decoded data to a program that can play it on
      your audio device.

 AUTHORS
      Maintainer:
           Thomas Orgis <maintainer@mpg123.org>, <thomas@orgis.org>

      Original Creator:
           Michael Hipp

      Uses code or ideas from various people, see the AUTHORS file
      accompanying the source code.

 LICENSE
      mpg123 is licensed under the GNU Lesser/Library General Public
      License, LGPL, version 2.1 .

 WEBSITE
      http://www.mpg123.org
      http://sourceforge.net/projects/mpg123




























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