I'm a newbie, so sorry about asking naive questions. For various reasons, I use WMP 12 for organizing my library under Windows 7. I know that I have to delete from and add to library in order to activate changes, but there are still a lot of things I don't understand.
I have set the genre tags of all my files, but when WMP first adds to the library, a lot of files end up with "unknown genre". I have to set the tags from within WMP, and those tags seem to be internal to the WMP database and not written to the file, so next time I rebuild the library, I have the same problem. However, this only happens to some of the files. I just realized that these problematic files (some mp3, some flac) all appear with empty length tag, and when I right click them and look at the details tab, all the tags seem to be empty.
Sometimes WMP and Mp3tag seem to edit different tags. Is there any way to access the tags that WMP use directly from Mp3tag?
I have some FLAC files, and I used WMP Tag Support Extender to make the appear in the library. One of them appeared with a strange Album Artist name. I could simply not find that name using Mp3tag. Then I tried it using Tag&Rename, and sure enough, I found it there. Do these programs read different sets of tags?
To me, from a distance, it looks as though you do not have pure MP3 tags but also APE tags. As they are higher in priority they may overrule the mp3 tags.
Have a look at /t/5060/1
about MP3 V1, V2 and APE.
Thanks for the suggestion, but I am leaning towards thinking that there is something wrong with the files.
They are all files that I have downloaded, sometimes it applies to all the files in an album, sometimes to just one file on an album (which is why I don't think it has to do with tag type), and when I use windows explorer or WMP, they don't seem to have any tags. No length, no track number, no nothing! But when I open in Mp3tag, the tags (listed as ID3v2.3) look fine, and the bad ones within an album look the same as all the other.
I recommend to scan your files with a stream checker like mp3val (although some in the forum don't like this tool for not yet explained reasons).
This should single out the dubious files. Perhaps mp3val can even repair them or some of them. You are then only stuck with the unwilling ones.
Actually, I had tried mp3val a couple of days ago, but I think I didn't see the repair button, so I gave up on it. Yes, that was stupid, but I was quickly trying out various tools on-line, and some of them are so bad that I don't want to spend too much time on each.
But after your recommendation, I tried it again, and it worked like a dream!