The documents says adding chapter marks is as simple as applying metadata file: http://www.ffmpeg.org/ffmpeg-formats.html#Metadata The document however wasn't specific to .mp4 format (the part specific about .mp4 is about segments, which doesn't look like chapter to me). Wikipedia says .mp4 has two kinds of chapter-marks: Quote from wikipedia:
1) In specially formatted text track (QuickTime); 2) In userdata atom (started by Nero Digital) can't interact with the sceneDescription, or via segmentDescriptor
So it seems the chapter mark in .mp4 is not standardized. The question is: if I load a custom metadata file with chapters in it, using metadata muxer and output a .mp4 file, what do I get? 1. I get the .mp4 file like that would be produced with QuickTime 2. I get the .mp4 file like that would be produced with Nero Digital And more interesting would be: what kind of chapter marks are supported natively by Android/iOS, since which version? A serious content producer would want to measure it to tailer the file he produces. Thanks!