mp3applygain
============

mp3applygain applies gain information directly to mp3 files, by
modifying the frames of the file.  It is designed to normalize
audio volume for playback by mp3 players which do not support
replygain natively (common in hardware mp3 players).

Usage
-----

  mp3applygain gain mod filename

gain is the replaygain as a file, which should be a floating
point number.  You can use rgain or a similar program to
calculate the replaygain for the file.

mod is an integer modification to the calculated gain. This
can be 0 to not modify the calculated gain.

filename is the name of the file to modify.

Example:

  mp3applygain 3.85 2 file.mp3

Caveats
-------

Applying gain to the mp3 modifies the mp3, and this does not
store any information allowing you to undo the change, though
you can rerun it with the gain and mod both multiplied by -1
to reverse it.  Do not run this program on original mp3s, only
on copies that are safe to modify.

History
-------

mp3applygain was forked from mp3gain 1.5.2. Almost all code
was removed, including the insecure embedded mpglib code and
code related to replaygain calculation. The only code remaining
is the code related to applying gain information to the audio
data frames.

Maintainer
----------

Jeremy Evans <code@jeremyevans.net>