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audio and video sync problem

RitualOfTheTrout - Feb 27, 2004

		RitualOfTheTrout	Feb 27, 2004
		Actually the video is noticably faster than the video.. but i know in a program I have I can correct this, but should I use negative millaseconds or postive?

		IBarracudaI	Feb 27, 2004
		Originally posted by RitualOfTheTrout@Feb 27, 2004 @ 06:30 PM Actually the video is noticably faster than the video.. :huh

		RitualOfTheTrout	Feb 27, 2004
		What the hell was I thinking.. I wrote it and I hardly understand it Basically I have a video file and the video is out of sync with the audio.. at the begging it works fine, then about half way through I notice a difference until the very end which is really off.. I think I know how to handle it now anyways.. perhaps this post should just be avoided at all costs.. haha :smash

		gameboy900	Feb 28, 2004
		What type of video file? If it's an AVI you can use virtualdub to alter the video frame rate to match the audio length. That should solve any sync problems where the video and audio start out correctly but then the video runs longer or shorter than the audio.

		Alexvrb	Feb 28, 2004
		Is it VBR? Virtualdub classic doesn't handle VBR... and even virtualdubmod has to be set to handle VBR. Here's what you can try first. Open it with virtualdub (or virtualdubmod if it is not an AVI). Tell me if it complains about it being VBR. I usually convert VBR to CBR myself for use in AVIs, as VBR is not a good idea for this file container. It is geat for something like Matroska though, which uses timestamps and is built for that sort of thing. But anyway, just find out what you're dealing with first.

		RitualOfTheTrout	Mar 1, 2004
		It is a mpg 1 file, I just converted it to a divx avi and then used a program called avi sync to fix it. But i am curious as to how I could have just solved this problem with virtualdub..

		Alexvrb	Mar 1, 2004
		Well, I was building on what gameboy900 suggested, we needed to know the file container (the extension, .avi, .ogm, .mpg, etc) first. But VirtualDubMod does handle mpegs. You can do all kinds of neat things with that.

		kahuna	Mar 1, 2004
		The easiest way to fix these types of problems IMHO, is to demux/edit audio/remux. Most of the time the video gets stretched and the sound is before the video. In this case, you can insert some silence into the audio. If it's the other way around, it's a bit trickier, but doable anyway. You have to find little bits of silence in the audio and delete them until the video matches up. You do this, then remux. A good free audio editor is audacity (audacity.sourceforge.net)

		Alexvrb	Mar 2, 2004
		If that is the problem in the first place... first thing you do is demux them both and compare time. Could still be framerate interleave issues, and you can interleave by either frames or time.