Video out of sync after using mkvmerge "append" function

[Odaik]

Hello,

I recently tried editing certain scenes out of a blu-ray rip I have (in the form of an MKV).

The original file contained:

-1 AVC 1080p video stream
-1 DTS MA audio stream
-2 AC3 streams (Movie commentary)
-3 English VobSub subtitle streams (Movie, Commentary 1, Commentary 2)
-1 Arabic SRT subtitle stream (movie)
-Chapters

What I did was use the "splitting" function of mkvmerge to split the MKV into 5 parts, at certain timecodes. I then deleted parts 2 and 4 (which were the scenes I did not want), and attempted to join parts 1, 3, and 5 together.

Watching each part individually, I get no issues.

I then opened part 1 using mkvmerge. I then used the "append" function to add parts 3 and 5. However, this produces significant audio sync issues. The part of the new file that used to be part 1 (to which the other 2 were appended) is fine, no sync issues with any of the streams. However, after getting to the part where the join was made, everything loses sync with the video. The subs/audio streams are all in sync with each other, but the video comes a little earlier than it should be.

At both points where the join has been made, the video speeds up significantly for about a second, then reverts to the normal frame rate.

Any ideas what is going on?

I realise I've made quite a few sync issue topics recently, so apologies for the spamming. I'd greatly appreciate any advice you guys might have on this.

Thanks (again),

Odaik.

EDIT: Looking through the MKV again, it seems that there is indeed no sync issue in the first part, then the video is about 3.5 seconds ahead of the audio/subs after the first join, then this gap doubles to about 7 seconds after the second join.

[gh0rowdy]

Yes i have quite the same problem here

2 files, both 1.30 h long .h264 files with dts sound. i just want to combine them into 1 mkv file.

with tsmuxer i can sync audio/videostreams of the second part, but as soon as i watch the video, the playback stops at the point the second file should start for about 2 seconds, then it plays on, but with NO sound! i have to skip forward for about 5 seconds, then the video is playing on as if nothing happened. Audio/Video is synchronized.... i really dont get it, why is there a 2 second stutter in the playback?


edit: if there is an answer here somewhere else, i apologize, but i googled my problem and this topic seemed to be the most recent one for me, that is quite similar to my problem.