Audio sync problems

[jjbtnc]

I have a downloaded a mkv file which has audio sync problems. I've demuxed the file and now have a divx video file and an ogg audio file - but what should be my next step ? The audio is out of sync at the beginning of the video (mouths move first then a split second later you hear the speech !!) but at the end of the video it seems pretty much perfect. It almost seems that i need to delete a fraction of a second at the beginning and then 'stretch' the audio out to it's original length - sorry about the terminology it's hard to explain what i mean. Is this possible ? If so what program can help with this preferably freeware ?

Also on audio sync problems, is there an easy way to work out how out of sync the audio is ? Is there any program that you can load the problem video (or a video and audio file if demuxed) into a program and say have a slider or some adjustment where you can alter the sound until it is in sync and then hopefully get a value in seconds as to how far out the audio was ?

Thanks for any help

[anonymez]

ogm/avi/mkv sync issues can be resolved with virtualdubmod. see here http://www.doom9.org/virtualdub_procedures.htm#mansynch

[jjbtnc]

Thanks for the link- definately come in handy in the future.

I did manage to fix it though - when i demuxed the original file i ended up with a avi file and an ogg audio file. I noticed that the audio file was 1 hour 28 mins long but also 0.45 seconds shorter than the video.
I used a program called Audacity and changed the speed of the audio file so it ran for longer to exactly the same length as the video file- worked out i had to change it's speed by something like 0.0102 % to get it the same length as the video file. Muxed them together and its almost perfect. perfect at the beginning and very slightly out (can hardly tell) at the end.

Thanks for your help

[anonymez]

you're welcome