I am not worried about the future of MP3Gain. Almost all the players now ignore APEv2 tags, which is fine, since the gain information is not stored there. Like I said before the Gain adjustment is made to the actual “global” gain settings in each frame of the MP3 itself. Regardless of changes in the ID3tag specification, the actual “playback” mechanism for MP3’s will not change. So as long as MP3Gain can write the APEv2 tags and read them to make their adjustment, changes in the ID3 Tag standard should not affect this.
Several years ago, players did attempt to read the APEv2 tags which would cause corrupted data to be displayed for “album/track/etc”. Mp3Gain even has the option to not write the APEv2 tags, or remove them on existing files. Now this does eliminate your ability to automatically “undo” your Gain changes, and you would have to manually track the original Gain of the file. But since all the current players ignore the APEv2 tag, it’s more an more a non issue.
What it comes down to is simply this.
1. Do you want to adjust Gain for multiple file formats? Use Replay Gain
2. Do you want to be able to change between album gain and song gain on the fly on your player? Use Replay Gain
3. Do you want to make sure that there are no actual changes to the actual MP3 file, original file? Use Replay Gain
4. Do you want to make sure that your gain adjustments can be read and played back on ANY device capable of playing MP3’s? Use MP3Gain.
