Replying to my own post, and more for reference for anyone else:
I found two distinct solutions, one for MP3 and one for MP4 (both open source):
- ISOBox4J:
https://contributions.coremedia.com/isobox4j
- Java Music Tag:
http://javamusictag.sourceforge.net
I also saw some non Java solutions:
- ffmpeg, but according to a post (
http://bbs.archlinux.org/viewtopic.php?id=43048 ), the API is in flux, so not of much use
- Atomic Parsley (
http://atomicparsley.sourceforge.net/ ), which does a good job.
One thing, in regards to MP4, is that I couldn't seem to find any references to an official set of meta-tags for the sorts of things specified in MP3's IDv3 tags. The only references are to the Apple defined tags. Am I to understand that people are just using what Apple has already defined, rather than making an independent set?
Providing logs, messages, configuration info (VLC, OS, Hardware) and a clear explanation of the issue always helps the problem solvers help you, even if they don't end up solving the issue. Just think what you would need if you were solving someone else's problem. Additional: Always looking for eager and capable MacOS X developers to join the VLC team - for more information
see here.