Link parkin’: mp4v2
A C/C++ library to create, modify and read MP4 files
This is the new MP4v2 project, a fork of the abandoned MP4v2 library project now archived at Google Code.
Seems a little more convenient, vice ffmpeg for working with .m4a
files as converted for or ripped by Apple’s Music.app. While primarily
a library, there are a few cli tools such mp4info and mp4tags.