Yes I have tried mp4muxer + mp4box,RESET_9999 wrote: Tue Sep 06, 2022 6:18 pm right, I only use FFmpeg for THD and DTS to mp4 then mp4box.
for ec3 its mp4muxer + mp4box
even directly extract from atmos.mp4 will break the "Complexity index".
For example in atmos.mp4 produced by mp4muxer:
Complexity index : 16
mp4box -add atmos.mp4 -new parse_by_mp4box.mp4
Complexity index : Not present / 16
I was wondering what other devices (TV's internal player, Bluray player) react to "Complexity index : Not present / 16".
If it's just ATV can't play it as atmos, then Apple is ridiculous.

