xenial (1) normalize-audio.1.gz

Provided by: normalize-audio_0.7.7-13_amd64 bug

NAME

       normalize-audio - adjusts volume levels of WAV or MP3 audio files.

SYNOPSIS

       normalize-audio [ options ] [ -- ] file ...

DESCRIPTION

       normalize-audio  is used to adjust the volume of WAV or MP3 audio files to a standard volume level.  This
       is useful for things like creating mp3 mixes, where different recording levels on  different  albums  can
       cause the volume to vary greatly from song to song.

       normalize-audio operates in two phases.  In the first phase, it analyzes the specified files as WAV audio
       files, and computes the volume of each file.  In the second phase, it applies a volume adjustment to each
       file to set each file's volume to a standard level.

OPTIONS

       -a, --amplitude=AMPLITUDE
              Adjust the RMS volume to the target amplitude AMPLITUDE; must be between 0.0 and 1.0.  If a number
              suffixed by "dB" or "dBFS" is specified, the amplitude is assumed to  be  in  decibels  from  full
              scale.  The default is -12dBFS.

       -b, --batch
              Enable batch mode: see BATCH MODE, below.

       -c, --compression
              Deprecated.   In  previous  versions,  this enabled the limiter, but now the limiter is enabled by
              default.

       --clipping
              Disable the limiter, and just clip any samples that are too large.  Same effect as -l 0dBFS.

       --fractions
              Display all values as decimal fractions instead of in decibels.  By  default,  volume  adjustments
              are  shown  in  decibels, and volume levels in dBFS, where 0 dBFS is the level of a square wave of
              maximum amplitude.

       -g, --gain=GAIN
              Skip the volume computation phase: don't compute the volume adjustment from the current volumes of
              the  files.   Instead,  just apply the given gain as a volume adjustment to all files.  As a plain
              number this is just a multiplier applied  to  all  samples,  If  a  number  suffixed  by  "dB"  is
              specified, all volumes are adjusted by that many decibels.

       --id3-compat
              Use  this  option  when  adjusting  MPEG audio files if your MP3 player does not recognize ID3v2.4
              tags.  See MPEG AUDIO ADJUSTMENT, below, for details.

       --id3-unsync
              Use this option when adjusting MPEG audio files if your MP3 player does not recognize  ID3v2  tags
              and  has  trouble  playing  some  ID3v2  tagged  MP3 files.  See MPEG AUDIO ADJUSTMENT, below, for
              details.

       -l, --limiter=LEVEL
              This controls the behavior of the limiter.   By  default,  all  samples  above  -6dBFS  (0.5)  are
              limited,  but  this option sets the limiting level to LEVEL. Setting LEVEL to 1 (or 0dBFS) does no
              limiting (clipping is done instead); setting LEVEL to 0 does limiting on all samples.  The default
              value is recommended unless you know what you're doing.

       -m, --mix
              Enable mix mode: see MIX MODE, below.  Batch mode and mix mode are mutually exclusive.

       -n, --no-adjust
              Compute  and output the volume adjustment that would set the volume to the target, but don't apply
              it to any of the files (i.e. skip the second phase).  If you use this option, your files will  not
              be altered in any way.

       --no-progress
              Don't  print  any progress information.  All other messages are printed as normal according to the
              verbosity level.

       --peak Adjust using peak levels instead of RMS levels.  Each file will be adjusted so  that  its  maximum
              sample  is at full scale.  This just gives a file the maximum volume possible without clipping; no
              normalization is done.

       -q, --quiet
              Don't output progress information.  Only error messages are printed.

       -t, --average-threshold=THRESHOLD
              When averaging volume levels for batch mode or mix mode, throw out any volumes that are more  than
              THRESHOLD  decibels from the average.  A high value here (say, 50) will make sure that the volumes
              of all files are considered in the average.

       -T, --adjust-threshold=THRESHOLD
              If an adjustment to be made to a file is  smaller  than  THRESHOLD  decibels,  consider  the  file
              already  normalized  and don't do the adjustment.  This is 0.125 by default, or 0 if the -g option
              is given.

       -v, --verbose
              Increase verbosity.  This option can be repeated for more messages.

       -w, --output-bitwidth
              Force output files to have samples that are W bits wide.  This option is  ignored  when  adjusting
              MP3 files.

       -h, --help
              Display usage information and exit.

       -V, --version
              Print version information and exit.

       --     Terminate option list.

MIX MODE

       This  mode  is  made especially for making mixed CD's and the like.  You want every song on the mix to be
       the same volume, but it doesn't matter if they are the same volume as the songs on  some  other  mix  you
       made  last  week.   In  mix mode, average level of all the files is computed, and each file is separately
       normalized to this average volume.

BATCH MODE

       When operating on a group of unrelated files, you usually want all of them at the same level, and this is
       the  default  behavior.  However, a group of music files all from the same album is generally meant to be
       listened to at the relative volumes they were recorded at.  In batch mode, all the  specified  files  are
       considered  to  be  part  of  a  single  album and their relative volumes are preserved.  This is done by
       averaging the volumes of all the files, computing a single adjustment from that, and  applying  the  same
       adjustment  to  all  the  files.  Some analysis is also done so that files with volumes that appear to be
       statistical aberrations are not considered in the average.  This is useful if you have albums (like  many
       of the author's) in which there is one "quiet song" that throws off the average.

MPEG AUDIO ADJUSTMENT

       MP3  files  are  "adjusted"  by setting a relative volume adjustment frame in their ID3 tags.  There is a
       frame for this, called "RVA2", that does exactly what  we  want,  and  is  a  native  frame  in  ID3v2.4.
       Unfortunately,  many MP3 players do not support v2.4 tags, and the RVA2 tag is not native in previous ID3
       versions.  In fact, adding an RVA2 frame to a v2.3 tag confuses some MP3 players.  Therefore, we are left
       with two choices when trying to add volume adjustment information to an ID3 tag:

       1. Go  ahead and upgrade the tag to version 2.4, and use RVA2 tags.  This is the default behavior, in the
          hope that eventually MP3 players will support v2.4 tags and this won't be a problem anymore.

       2. Upgrade the tag to only version 2.3.  Instead of RVA2, use an "XRVA" tag with the same  format  as  an
          RVA2  tag.   This  isn't a native frame, but since it starts with an "X", it's considered experimental
          and therefore legal, according to the ID3 spec.  The --id3-compat option turns on this behavior.   The
          disadvantage  of  the  first  method  is  that your MP3 player may no longer read the ID3 tags on your
          files.  Bug the author of your favorite MP3 player to support ID3v2.4 tags!

       The disadvantage of the second method is that the XRVA frame is only recognized by  the  xmms-rva  plugin
       that  is  packaged with normalize.  On the other hand, I don't know of any MP3 players that recognize the
       RVA2 frame, either, so it may not make any difference.

       The other option related to ID3 tags, --id3-unsync, is only necessary  for  compatibility  with  old  MP3
       players  that don't recognize ID3v2 tags at all.  If your MP3 player complains of garbage at the start of
       tagged files, or is unable to play the files at all, turn this option on.  This option should never hurt,
       but if your MP3 player knows about ID3v2 tags, you don't need it.

CAVEATS

       Note  that  your version of normalize-audio must be compiled with MAD library support to analyze MP3 file
       volume levels.

AUTHOR

       Chris Vaill <chrisvaill@gmail.com>

SEE ALSO

       sox(1)

                                                14 September 2005                             NORMALIZE-AUDIO(1)