Bug report - Exporting tracks, existing meta data gets messed up

[BG-UK]

Audacity 3.3.2 but bug on previous versions too
Windows 10 mostly (plus other versions on other laptops)

I import multiple mp3 music tracks, do loudness normalization and clip up the tracks as needed.
All the tracks already have their meta data filled in, artist, title, year, genre, etc…
When exporting multiple tracks (still as mp3), the meta data gets mangled and does not match the track.
For example, I have just exported 31 tracks from different artists, they now all have the same meta data for these fields:
Artist: The Shapeshifters
Album: Sister Sledge - Lost in Music
Year: 2023\2023
Comment: Cover (front)

Also, they now have a track number which is not needed:
Track number: 1 … 31

Please fix this or add an option to retain file meta data on export.

Currently I use mp3tag to blank the incorrect columns, but ideally I want to retain the meta data rather than have to fill them back in.

[jademan]

@BG-UK

Currently I use mp3tag to blank the incorrect columns, but ideally I want to retain the meta data rather than have to fill them back in.

Good idea. Please see: Tags are missing information in other some other

[DVDdoug]

I’m a little surprised but there are 2 popular variations of ID3 tags (ID3v1 and ID3v3) that aren’t interchangeable, and other file formats use completely different tagging standards so it’s more complicated than you might think. And tagging is a “weak area” for Audacity, most notably it doesn’t support Album artwork.

@BG-UK

I import multiple mp3 music tracks, do loudness normalization

Check-out MP3Gain. It does loudness normalization without decompressing the MP3.

It also doesn’t touch the metadata.

There is a limitation that without decompressing, MP3 can only be adjusted up or down in 1.5dB steps. But that will normally get matching within 0.75dB

When you edit an MP3 in Audacity, or any regular audio editor, it’s decompressed when you open it. Then when you export it get’s re-compressed and you are going-though another generation of lossy compression and some “damage” accumulates.

You may not hear any quality loss but it’s something you should be aware of and you should try to minimize the number of times it’s compressed/re-compressed.

and clip up the tracks as needed.

There is another special purpose program called Mp3DirectCut that can do some limited editing without decompressing. I think it also doesn’t touch the metadata.

currently I use mp3tag

Mp3Tag can copy from the old files to the new file. I’ve never tried that feature but you can probably do that in bulk for a whole album, etc.