Tag for comments is ignored for MP3, FLAC, Ogg

[jus]

If you use 3rd party applications (iTunes, Rapid Evolution, Mixed in Key...) and write comments to the proper id3 field in you mp3, the tag is ignored and the comments column stays blank in Mixxx.

Mixxx 1.8beta2
Issue reported on all supported platforms.

Forum discussion here: http://mixxx.org/forums/viewtopic.php?f=1&t=1624

[Irwin J. Céspedes B (cespedesbirwin)]

Mixxx doesn't read ID3 "Comments" information.

[RJ Skerry-Ryan (rryan)]

It turns out that Mixxx does not read the comment field for FLAC, MP3, or Ogg Vorbis, though it does for the M4A plugin. The change to do this was fairly simple so I added it to the 1.8 branch. I've confirmed with an Ogg, a FLAC, and an MP3.

However, an outstanding problem in Mixxx is that if file metadata ever changes, Mixxx will not notice, as it only reads it at import time.

[RAFFI TEA (raffitea)]

There might be a way detect changes in audio tags: My idea is to modify the computation of the library hash. As far as I know, it only considers the file names but not the file sizes for computation. If the tag changes, the file size or modified date alters which result in a new library hash. And this means we have to rescan the folder.

[Albert Santoni (gamegod)]

Using either the filesize or date modified would work, with the latter probably being more reliable. Presumably the files are all already being stat'ed by QDirList or whatever I used in the library scanner, so I don't think there'd be any noticeable performance hit in changing the hashing to do that. The only reasons I did it based on filenames was for simplicity.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/5496