AC3 Sync problem out of MKV file

[betão]

Hi there everybody. I have a problem which is: I have an MKV file which has the audio out of sync by one second or two. The audio comes before lip movement, so, I need to put it ahead a couple of seconds. I demuxed the file and I have an AC3 audio file plus an h264 (MPEG-4) video file. Is it possible to resync the audio then mux everything back together again? Which program should I use to do this? I am sorry if the questions have been answered somewhere. As far as I read the posts didn´t see anything like it. Thanx a million guys.

[AlanHK]

Delaycut can add a delay to AC3.

[johns0]

Mkvmerge can add a delay and mux to a mkv at the same time.

[betão]

Thank you mates. Alan, as a matter of fact what I need is to advance the audio a bit, not delay it. As I had said, audio happens before voice, so I have to make it ahead. I tried AC3 Delay Cut 1.2.1.2 - that´s what I´ve found on the net in a haste! Didn´t work, or I didn´t heve enough patience to know how that worked. johns, how do I do that "at the same time"? Anyway, what I think I really have is a video file with an fps problem. Video stammers now and then. I don´t think it´s hardware 'cos others are OK. Vid fps is 29.97 - don´t think is blu-ray rip. Looks more like HDTV rip. Bad encoding
Thank you again guys. Sorry for the noob stuff!

[AlanHK]

Thank you mates. Alan, as a matter of fact what I need is to advance the audio a bit, not delay it.

Delaycut can do that too (thus the "cut" part of the name).

I tried AC3 Delay Cut 1.2.1.2 - that´s what I´ve found on the net in a haste! Didn´t work, or I didn´t heve enough patience to know how that worked.

That appears to be the same version as here.
It works very efficiently.
Select "Cut" and then the start position, in milliseconds. e.g., to advance 1 second, use 1000.
The end is the length of the track, also in milliseconds. Working that out is the only difficult part.
It will tell you the original length in minutes and seconds ... the gui isn't perfectly integrated with the command line.
Then "process" and it will create the new AC3 file.

[betão]

Thanx again. I need to look deep into that. Haven´t figured things out! You mean, I have to enter the beginning of the whole track, where I want it - like 2secs ahead: 2000ms - and then the very end of the whole track? I have to calculate that? I´ll give it a try. Thank you for the patience.

[AlanHK]

Thanx again. I need to look deep into that. Haven´t figured things out! You mean, I have to enter the beginning of the whole track, where I want it - like 2secs ahead: 2000ms - and then the very end of the whole track? I have to calculate that? I´ll give it a try. Thank you for the patience.

Right.
I just pull up the Windows calculator and do that.

[betão]