Muxing including mp4 metadata appreciated

[WernerBleisteiner]

It'd be nice to to include some typical mp4 metadata. Especially
• chapters marks/time stamps
• ID3 tags (title, author, etc.)
in order to provide the same UX with video files muxed with FFMPEG/FFMETADATA (well, for the time being until there's more AC-4 support in FFMEPG as currently the 'raw' option in 6.1).
Alternative: being able to use a h64/265 video in a mp4 container that already includes that sort of metadata and forwards it unaltered.
Thanks.