Audio becomes out of sync only later in the video.

[zanzar]

i used an mp4 as a source to re encode it , i didnt change the frame rate and used the source for everything.
when i combine the audio file of the source MP4 and the output mkv , the audio becomes out of sync only 20~ ish into the video.

its like there is a difference in frame rate speed or something that makes the audio go out of sync only after a while passed.
for the source video the audio and video time are the same , Duration: 24mn 51s.
and the output video is 24mn 50s you might think , well there is a 1 sec delay.
no at the beginning of the video its synced and as it goes on , its get more and more out of sync and is at its worst in the end.

any idea how to fix this? i added the media info text files of each one

[sneaker]

This looks odd.

Frame rate mode : Constant
Frame rate : 24.000 fps
Original frame rate : 23.976 fps

Either the constant framerate is detected wrong or it's variable framerate and your process doesn't account for this. Since you haven't posted any details about your process nor the source/output files we cannot tell you what you did wrong. A first small test would be to set video fps to 24000/1001p in mkvmerge when muxing.


P.S.: You mkvmerge version is outdated (2016).

[zanzar]

This looks odd.

Frame rate mode : Constant
Frame rate : 24.000 fps
Original frame rate : 23.976 fps

Either the constant framerate is detected wrong or it's variable framerate and your process doesn't account for this. Since you haven't posted any details about your process nor the source/output files we cannot tell you what you did wrong. A first small test would be to set video fps to 24000/1001p in mkvmerge when muxing.


P.S.: You mkvmerge version is outdated (2016).

i didnt tuch anything exept running scripts on the frames with (core.ffms2.Source) and not messing with anything else

[sneaker]

Are you using vspipe? You can make vspipe output timecodes via --timecodes option. Then use those as input to some encoders and mkvmerge. Or use mkvextract's timestamp extraction option to extract them from the source.