#9996: When remuxing dolby atmos mkv to mp4, complexity index is not present. -------------------------------------+---------------------------------- Reporter: BlueWindy | Owner: (none) Type: defect | Status: open Priority: normal | Component: ffmpeg Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+---------------------------------- Comment (by Balling): So basically you need to change it from 646563330E00200F000000000014 (or whatever) to 646563331800200F00011000000018 or (last 0x18 byte is what signals joc_complexity_index, this means 0x10 is decimal 16, and that increases the size of the box from 14 to 15, size 15 is encoded with 0x0000000F) after ec-3 box. So basically you need to find 64656333 + some bytes and modify it to be 646563331800200F00011000000018 then you need to change the size of that field from 0E to 0F (right before dec3), then hardest part, you go to next box (btrt, if it is not present -c copy the mp4 to new mp4 and ffmpeg will write btrt box), delete one of btrt box 0x00 bytes (62747274000000000 becomes 62747274000000) and then (most magical part) you decrease the size of btrt box to 0x13. BOOM! Or you can -c copy it to mkv or to .ec3 those are both supported by new player: 646563331800200F00011000000018 -- Ticket URL: <https://trac.ffmpeg.org/ticket/9996#comment:8> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker