As you may be aware, Windows Media Player 12 (and Windows 7 media foundation in general) corrupts tags in MP3 files without user intervention: the extended tags, such as ALBUMARTIST, seem to be overwritten or at least no longer properly read by non-Microsoft software. This topic has been under discussion on Microsoft's board for many months, but getting Microsoft interested in fixing this bug has proven impossible, for example see here:
Recently a new post has been added to this old thread claiming that the tag data is still in the files, it is just written in a way that does not adhere to ID3 standards:
"Sorry to resurrect an old topic, but I have some insights as to why the tags are corrupted in the above scenario. I recently made a tag reader and while debugging it, I found that WMP does not store Frame sizes as SynchSafe integers, which is required by the official ID3v2 specifications. Rather it stores the sizes as simple 32-bit unsigned integers, which when treated as SynchSafe int will give wrong result for all values bigger than 127. Smaller frames with size less than 127 , like those which contain title, album etc, are read correctly. But the album art (Frame 'APIC') contains bitmap which is larger than 127 bytes. Hence unless treated as 32 bit uInt, all frames appearing after APIC, or any other larger-than-127-bytes frame, will not be read correctly by tag readers which follow the ID3v2 standard.
The corrupt tags can be fixed by modding available open-source tag readers to read frame sizes as uInt32 but save the same sizes as 32bit synchsafes. "
I am one of the many people who have had their music collections corrupted by WMP and haven't had the energy to go through all the files and recreate the extended tags from scratch. Since it seems as if the data is still there according to the above post, would it be possible to add a feature to MP3Tag that would extract this data and fix the tags automatically? I (and I am sure many others) would be extremely thankful!
Thanks and regards!