Is there an easy way to add chapters to existing movie files?

Note:

• Actually, I’m not 100% sure if they’re called “chapters” in video files, but it’s the same concept as DVDs.

• I assume this differs with the video encoding, but any help at all is progress! I have video files in various formats (although .mov, .mp4, and .m4v are my most common).

• I’m on Mac OS X, but I posted here (instead of the Apple Q&A) because I figured any answers may be useful to other non-Apple power users.

• Apple-native, application-based solutions preferred (usability is top of my list). However, command-line programs and utilities that do the job are just as welcome.

• Please share any indirect-but-related wisdom you may have on this topic.

Thanks!