ISO SAX
Callback-based ISO media file parser
ISO SAX is a callback-based parser for ISO container files (ISO/IEC 14496-12), e.g. MPEG-4.
The libraries that are out there either won't run on Android, have many megabytes of dependent JARs, or will fail to parse your favorite media file due to a "technicality" it thinks it is mal-formed.
For example, a perfectly good M4B file gets declared "invalid" because it had a video track in it (the album art), along with the sound track. Really!? Don't let these libraries "judge" the format...