Created attachment 375040 [details, diff]
patch adding compilation, gapless, and genretype support to mp4tags
mp4tags does not currently support setting the compilation, gapless, or genretype tags. That attached patch updates mp4tags to do so. The patch has been submitted upstream:
but their last release was May 2012, so :(. It would be nice for this to be added to the gentoo ebuild.
Are you aware of a new upstream to submit this to?
Looks like https://github.com/sergiomb2/libmp4v2 is active; the patch still applies cleanly to current master. I'll submit a pull request. There still aren't any new releases though...