Can't sync audio muxing mp3 from AVI with MKV video

[cianoz]

Hello
I have some episodes of a TV series in MKV format (h264) with English ACC audio and I have the same episodes in old AVI (Xvid) format (Xvid + mp3) in my language.

I'd want to mux the videos merging the audio from the AVI with the MKV video and I'm trying to use MKVtoolnix for this task. The audio from the AVI is not in sync with the MKV video so I'm trying to sync it, but I can't to work it out.

The length of the videos are slightly different, since the MKVs are about a 1 minute longer and the addition is at the end of the videos. I mean, for example, that 1h 4m is the same common part of both the video but the MKV has an extra 1m 10s at the end. So this is not the problem, IMHO.

Using an appropriate value for the Timestamps and default duration > Dealy (ms) I can sync the START of the video, but as I fast forward / seek the resulting video the audio becomes out of sync.

Am I missing some settings in MKVtoolnix or something else? Or is it preferable to use another software?
Advices?

Thank you

[sekininsha]

I can sync the START of the video, but as I fast forward / seek the resulting video the audio becomes out of sync.

You should verify that the movies have the same fps (23,976fps or 25,000fps see with MediaInfo) in addition to the same version, television series may have some differences between scene changes.
With mkvtoolnix you can apply simple delays, when this does not work you have to edit the audio correctly, sometimes cut or add .ms of audio.

[ProWo]

Extract the audio in your language from the avi file.
Then load the mkv video (with english audio) in Mpeg Video Wizard

https://www.heise.de/download/product/mpeg-video-wizard-19617/download

and the extracted mp3 (from AVI) in the audio track line.
Select for both tracks "View Audio Peaks".
So you can compare the two audio tracks directly.

[cianoz]

Thank you for the replies, both
@sekininsha, Yes you're right friend, tracks have different frame rate, I didn't think to that.
I spent some time in making test, converting the PAL framerate to NTSC framerate and got partial success. Partial because audio starts now synced but the more the video goes forward the more the sync goes out again. So I suspect that the two videos has some differences in scenes, too, not only a fps issue.
This would be much more difficult to fix.
Anyway tanks for your tips.

[George53]

You have to extract the audio in your language from the avi file.Then load the mkv video (with english audio) in Mpeg Video Wizard.I think thats work properly.