15. Changed: The "Album Gain" for a file with no album is now the same as the track gain for that file. (so it's treated like an album of one)
I couldn't make this work in a quick test.
I added an analyzed, but unimported MP3 file (thus without the album gain value) to a PN playlist of several files that had the album gain value. This made all files in a PN playlist play without the "Automatic based on current playlist" adjustment in the Album mode.
The same happened in the Track mode when I added an unimported & unanalyzed wave file to PN.
Also, this wave file played always at the same unadjusted volume, with or without other analyzed files in the PN playlist.
If you can't easily reproduce this I'll do more testing and post a detailed report.
EDIT
I think you have made a mistake when designing this function. You have made MC12 to automatically copy the track gain value to the album gain field and thus change the library data.
I have a folder that contains 2800 various old single tracks with partly incomplete tags. These files are imported and analyzed. Several of them have identical album names even though they are from different sources and are not from the same album or recorded at the same volume level. In an MC11.1 library most of the files have correctly only the track Replay Gain value.
Now after this change the library data shows new album gain values. Many of these Album Gain values are now incorrectly the same for completely separate tracks because they have the same album tag. Also, these values are now incorrectly different from the Track Gain values.
This explains also why the analyzed, but unimported MP3 file was not replay gain corrected at all in the album mode.
You should not have touched the library logic, which worked pretty well.This change should happen only in the playback DSP module:
1. Read and use the Album Gain value as before
2. If the Album Gain field is empty read and use the Track Gain value instead.
3. If both values are empty use the "automatic average" system, which seems to be not working at the moment --- or perhaps the user defined value option if introduced. This "number 3" needs more testing and discussion after the possible bug is fixed so that I can try it.