Provided by: normalize-audio_0.7.7-16_amd64 bug


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


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


       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

       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.


       -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.

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

              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.

              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.

              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

       -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.

              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.


       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.


       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


       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.


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


       Chris Vaill <>



                                        14 September 2005                      NORMALIZE-AUDIO(1)