When ffmpeg converts one mkv file to mp4 it finds errors in it

[Yuri]

This mkv file (​https://people.freebsd.org/~yuri/problematic-for-ffmpeg.mkv) has no errors according to this ffmpeg command:

$ ffmpeg -v error -i "problematic-for-ffmpeg.mkv" -f null -

Then the above file is converted to mp4 with this command:

$ ffmpeg -fflags +genpts -i "problematic-for-ffmpeg.mkv" -codec copy -r 24 "problematic-for-ffmpeg.mkv.mp4"

to this file: ​https://people.freebsd.org/~yuri/problematic-for-ffmpeg.mkv.mp4

Now problematic-for-ffmpeg.mkv.mp4 fails the same check:

$ ffmpeg -v error -i "problematic-for-ffmpeg.mkv.mp4" -f null -
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 371 >= 371
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 382 >= 382
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 1448 >= 1448
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 1458 >= 1458
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 2514 >= 2514
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 2524 >= 2524
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 2535 >= 2535
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 3590 >= 3590
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 3601 >= 3601
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 3611 >= 3611
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 4667 >= 4667
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 4677 >= 4677
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 5743 >= 5743
[null @ 0x85f883e00] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 5754 >= 5754

ffmpeg-4.4.2_5
FreeBSD 13.1

[Balling]

Why do you need +genpts and -r options -r option will not help you make it CFR. Besides your original file is 25,060 fps, constant framerate.

[mkver]

Why are you setting the genpts flag? It is designed for avi, a container that only stores dts (or actually, was not designed with reordering in mind).

[Balling]

That happens even with just ffmpeg -i problematic-for-ffmpeg.mkv -c copy problematic-for-ffmpeg.mkv.mp4

[hydra3333]

can't remember how to subscribe to a thread, but replying seems to do it ?