My music files are mostly in pairs of a flac file and a converted mp3 file, e.g. a-filename.flac and a-filename.mp3. Is there an automatic way of copying the tag fields from each flac file to the corresponding mp3 file?
You could sort by extension, copy all tag information from the FLACs then paste into the MP3s. However, you need to have exactly the same number of MP3s as FLACs. Also, you should make sure that the FLACs are sorted in the same way as the MP3s, so:
Unfortunately, I have a few more MP3s than flacs - they're not quite a 1:1 match. Any other suggestions?
Going on with the 1:1 match proposal I would try to make both groups of filetypes synchronic.
Create some dummy empty (flac or mp3) files, so that the number of files overall and their individual sorting position do match to the corresponding file in the mp3 group.
Find a proper naming mask for the dummy filenames for easy deleting the dummy files afterwards.