Overview:
ReplayGain [Add explanation of lossless ReplayGain, how it does not modify the original music data, only writes a metadata tag, usually uses Ogg Vorbis tags instead of mp3 tags, etc.]
WaveGain is an application of gain algorithms to standard PCM wave files. Where it differs from the other applications of this principle is that the gain adjustments are applied directly to adjusting the scaling of the samples. In other words, the option to write tags that can be read by other applications to apply the gain adjustment does not exist, so the adjustments are made directly to the data on-file. Therefore, in the strictest meaning of the word, this process is NOT lossless.
Samples of Song Using Different Techniques and Players
The following song has been encoded to allow comparison of the differences between the original song, the song with ReplayGain applied, and the song with WaveGain applied. To fully understand the differences, you will need a two different audio players, one that supports ReplayGain (foobar2000) and one that ignores ReplayGain (most currently ingore replay, Iâ??m using
Yahoo! Music Engine Beta 1 v1.0.1.108).
The song used for comparison is the first 60 seconds of the song â??All Along the Watchtowerâ?? performed by Dave Matthews on 1993-04-09. This song was chosen because 1) it was recorded from the audience and is relatively quite and requires gain adjustment and 2) because it can be freely redistributed due to the DMB taping policy.
| Files | foobar2000 Result (supports ReplayGain) |
Yahoo Music Engine Result (no ReplayGain support) |
| Original, unaltered flac mp3 |
Song is too quite. Original data unaltered. |
Song is too quite. Original data unaltered. |
| ReplayGain applied flac mp3 |
Song is proper volume. Original data unaltered. |
Song is too quite. Original data unaltered. |
| WaveGain applied flac mp3 | Song is proper volume. Original data altered. | Song is proper volume. Original data altered. |
Note: Green is Desired,
Red is Undesired
What the above illustrates is that it is possible to adjust the volume of a
song so that is is not noticeably louder or quieter than other songs in your
music collection. If the playback device supports the ReplayGain header
metadata, the relative volume of the song can be altered without modifying the
original song data. However, if the playback device does not support
ReplayGain, the original song data must be altered in order to achieve the
proper playback volume for multiple songs.
Song Gain vs. Album Gain
How to apply ReplayGain tags using foobar2000
Links
http://wiki.etree.org/index.php?page=ReplayGain
http://heaven.ravenquest.net/audio/info/info8.htm
http://wiki.hydrogenaudio.org/index.php?title=Replaygain
http://www.soundstageav.com/audiovideotrends/20050415.htm
http://flac.sourceforge.net/documentation.html
http://www.soundstageav.com/audiovideotrends/20050101.html
http://forums.slimdevices.com/showthread.php?t=13899