Tags are an ongoing “weakness” in Audacity. And it doesn’t support embedded artwork.
I assume the difficulty is that different audio formats have different tagging standards.
…Actually it does leave then as they are (unless you overwrite your old file). They just don’t always get copied-over correctly or completely to the new file when you export.
MP3tag can copy from one file to another and I think there’s a way to copy them all at once and maybe batch-copy for all of the files in folder. (It works on all of the popular formats, not just MP3.)
Metadat handling has a lot of bugs in Audacity as @DVDdoug implies.
See this super-bug that lists all the known metadata issues:
In particular see this one:
You will note from the comments in the thread for this that Muse have no plans to fix these for Audacity 3.x - and they remain somewhat vague about metadata handling in Audacity v$ which is currently under development.
As DVDdoug wrote, Audacity does leave the tags “in the audio file” alone. They are not changed in any way.
What Audacity does not do is to copy all of the metadata from all kinds of audio file into the Audacity project. This means that if an audio file contains metadata that is not supported by Audacity, then that metadata is not copied into the Audacity project, so Audacity cannot add that metadata to files that it exports.
The underling reason for this limitation is that audio metadata is a mess, and that has nothing to do with Audacity. Other than for a few modern file types such as FLAC and OGG, the “standards” are like the Wild West:
Some formats put metadata at the start of the file, some put it at the end.
Some formats allow the metadata to be at the start or the end, or both.
WAV does not formally specify metadata at all - it allows developers to add their own custom metadata
MP3 has multiple “id tag” versions, and many MP3 players use their own custom tags.
Media players and tagging applications may use their own standards that need not be compatible with other applications.
Audacity, which is primarily an “audio editor” (rather than a “metadata editor”), works around this mess by supporting common tags as consistently as possible across the formats that it supports.
I was not aware of this. I always put the moov atom at the start of the file because I pre-load the metadata in the <video> player HTML on my web pages. I guess this doesn’t work on all media types.
And it doesn’t support embedded artwork.