MP3Gain

MP3Gain is a free, platform-independent program that can normalize audio files of type mp3. Using Replay Gain the audio files adapted to a user-specified volume, without affecting the data stored in the file actual audio data is touched.

The program was written in C and is available in many languages. It is released under the GPL license.

Operation

MP3Gain can modify the files in two different ways:

• Writing metadata
• Change in the MP3 data, where information is stored to revoke the action as metadata in the audio file

In both cases, is first calculated on the replay gain algorithm, the rate of change of volume. This is done either per song or album.

In the first case, the program writes the calculated rate of change as the date in APEv2 format into the file. This tag can then be read by other programs that have ReplayGain implemented.

In the latter case, the average volume in each MP3 frame is changed and it will make the change to make stored as day undo information. These changes do not change the actual audio information, so are " lossless", and can be completely reversed if the undo information is stored in the file, which is optional.