audio sync

roxylee wrote on 3/4/2008, 1:01 PM

I am capturing 90 to 120 minute videos. i'm noticing that the audio is getting progressively out of sync. it's fine for about the first 10 minutes, but the end of the capture, it's out of sync by several seconds, very noticable. i've been able to resync manually, but is there a setting inside of capture that i'm missing that maintains the audio sync?

Also, any "tips" on syncing manually? I'm marking the video at the point of speaking, based on visual lip movement and the same when i hear the sound beginning. then i'm ungrouping the segment, and moving the audio by the difference, based on the time change between the two marks. I don't always have a clear lip sync, then it's just drag and try until is seems to match, very tedious.

any suggestions would be great

roxylee

Comments

Chienworks wrote on 3/4/2008, 3:17 PM

First of all, how are you capturing? What is the source material? What hardware are you using? How is it connected to the computer? What program are you using to capture with? What file type are you getting when you capture? Answer these and we might be able to very easily tell you, "don't do that!!!! do this instead" and it will fix all your problems.

Syncing is always a pretty manual job. It sounds like the audio is running a different speed than the video, since you say it progressively gets worse. Just moving the audio event isn't going to fix this because you'll only ever get it in sync at once instant. Fixing it anywhere else messes up everything else.

Let's say you determine that you have it in sync at the beginning, but the audio is 4 seconds short at the end. If you hold the Ctrl key down and drag the end of the audio event to the right 4 seconds it will stretch out the audio to be the same length. Then you can find one good spot with clear lip movements for syncing and everything will be right.

Himanshu wrote on 3/4/2008, 7:34 PM

In addition to all the questions asked...did you have dropped frames during capture?

roxylee wrote on 3/5/2008, 9:25 AM

I'm capturing using a sony 8mm deck (i have to get the model number when i'm back at that location), going thru S-video and red/white audio jacks that join into a mini stero plug that plugs into the soundcard input. again, i'll have to get back to the soundcard, but i believe it's a creative card. (will device manager show the model number?), using a dual core athlon 64 desktop with 2gb ram onto an external firewird 500GB hard drive. using sony vms to capture. i'm saving to an avi file type.

I like, but haven't yet experimented with, the suggestion of stretching (or condensing) the video stream (am I correct, I have to ungroup them first?) the amount that it is out of sync at the end of the event.

roxylee

Chienworks wrote on 3/5/2008, 9:52 AM

Model number of the deck and card aren't really important, don't worry about them. Capturing this way though is very prone to sync errors. There are devices available that will convert the analog output from the deck to DV which is a much better way to capture and the resulting files will be virtually free of sync errors. Canopus makes a line of ADVC devices that are all very good. The ADVC 110 is the current favorite and can usually be found for about $200 to $300. You'll also need a firewire port on your computer. If you don't have one then a card can be had for about $10.

Yes, ungrouping is required. Be sure to regroup after making the adjustment.