[filler56789]

Originally Posted by Selur

Sadly Mosu is not interested to spend time on MPEG-4 ASP (https://gitlab.com/mbunkus/mkvtoolni...note_425653157).

At least he has always been very honest, which surely is a good thing
Quite different from the gpackers who shamelessly lie about "lack of time" because they don't have the courage to say "give us N thousand US$s and only then we'll do what you want us to implement in our software".
ANYWAY: "everybody" creates ASP-in-AVI because "nobody" creates ASP-in-MP4, this the reason why ASP in Matroska by default uses the VfW-compatible mode instead of the "native" MPEG-4 mode

Originally Posted by Selur

- the GPAC Team fixed the muxing of MPEG-4 ASP raw streams (https://github.com/gpac/gpac/issues/1609), so MP4Box can be used to mux raw MPEG-4 ASP to mp4 again.

Just keep using the old builds of MP4Box, problem solved
What isn't broken doesn't have to be "upgraded"