There are different things. The "actual" adjustment is made in each frame in "global_gain" element (MediaInfo shows this). Then mp3gain may also add APEv2 tags to undo adjustment or make it more precise (global_gain is 1.5 dB steps).
Quote:
Originally Posted by hello_hello
The way I read that, space was reserved in the MP3 tag for programs to store information in order to losslessly undo the previously applied lossless volume changes
|
There is no reserved space for either global_gain or APEv2. global_gain is always present in every mp3 file. Just needs to be altered. The (optional) APEv2 tag will be added.