Creating MP4/M4A files with Chapter marks

Question

I am trying to join together several audio files into one mp4/m4a file containing chapter metadata.

I am currently using QTKit to do this but unfortunately when QTKit exports to m4a format the metadata is all stripped out (this has been confirmed as a bug by Apple) see sample code. I think this rules QTKit out for this job, but would be happy to be proven wrong as it is a really neat API for it if it worked.

So, I am looking for a way to concatenate audio files (input format does not really matter as I can do conversion) into an m4a file with chapters metadata.

As an alternative to code, I am open to the idea of using an existing command line tool to accomplish this as long as it is redistributable as part of another application.

Any ideas?

Answer 1

Audiobook Maker does something like this, and I believe it uses ffmpeg under the hood. It's open source, so maybe its worth a look?

Answer 2

Depending on where the bug is, you could try going straight to the QuickTime C APIs to write the movie file. You might also try adding the chapters track using the C APIs.

Any word on when Apple will fix the bug? I am planning to create enhanced podcasts with QTKit, and need this to work.

Answer 3

I discovered these guys: sensoryresearch who license an API for writing chapter/text/link tracks to MP4s (which is what an M4A is).