Best way to synchronize two video tracks

lukearndt wrote on 12/28/2004, 9:53 PM

I've been doing more work with multiple angles lately (weddings, church events, et cetera), and I was just wondering if there's a better way to synchronize two video tracks than what I've been doing. Here's my method:

Both videographers will keep the camcorders running the entire length of the event, without any pauses or stops in recording. I'll then capture both clips, drop them both into MovieStudio. I'll zoom in very closely on the two audio tracks and try to line them up visually. Then, I'll try playing both audio tracks back simultaneously to make sure there isn't any "echo." After that, I'll mute the unused audio track.

So my question is ... is there a better way to synchronize two tracks? Is it always done "manually" like this? Or is there some more advanced software that might automatically synchronize? I just wonder because I know there's timecode or datacode, and I would think that something could be done with that.

Any advice would be appreciated! By the way, the two camcorders we use are a Sony PD150 and a Sony VX2000.

Thanks!

Comments

Chienworks wrote on 12/29/2004, 4:57 AM

Datacode would only help if both cameras had their clocks exactly synced before recording. Timecode would only help if the cameras were locked together and started in sync.

While this may be difficult to arrange at a wedding, the usual method is a sudden audio/visual cue that both cameras pick up. Hollywood uses a clapboard for this; the camera records the clapper hitting the board and the audio recorder picks up the "clap" sound. The same principle applies with two cameras. You could have both cameras point towards someone standing in the back who claps his hands (very lightly) before the ceremony starts. Even if you don't get the sound of the clap, lining up the video tracks so that the frames where the person's hands are together match will get you to within a 60th of a second. This should be close enough since you're only using one of the audio streams. In fact, in video this is the closest you can get; even if you slip the clip to line up the audio exactly with quantize to frames turned off, Vegas will sample the slipped video at project frame intervals.

In absence of a specific predetermined event, i'll look for a case where something quick and definate occurs in the video. Perhaps when the father's fingers touch the bride's veil, if both cameras see it, is a good event to look for. For a recent dance video i worked on the lead dancer did a quick guesture with her index finger right at the beginning of the first dance. It was easy to find this frame on all three videos and sync from there.

lukearndt wrote on 12/29/2004, 10:24 AM

Thanks for the reply, Chienworks.

Do you know if it's possible to set the clocks of both cameras to exactly the same time -- or within a fraction of a second? Datacode seems like it would work, but I just wonder how you can initially get the two cameras' clocks synchronized. Also, assuming you had them set perfectly, how would you "use" datacode when editing it? I normally just drag and drop the videos into Movie Studio, but I assume this would be a different method?

That's a good idea with the clapboard and such. I find that if you have both cameras picking up the audio, that makes things much easier since you're able to line up the tracks one on top of the other and you can be very precise. I was basically wondering if there was some "official" way to do this where, say, the program will automatically lock the two cameras in sync. But maybe it's always a matter of just lining them up manually and going from there.

Steve Grisetti wrote on 12/29/2004, 11:47 AM

Chienworks way IS the "official" way to do, Luke.

Short of a clapper, you can try synching up your two video layers by watching for a camera flashbulb flash, a cough (which you may be able to see as jump on the audio track) or even the groom passing out.

I've also played both audio tracks at once when I thought they were almost in sync. If they're a little off, it sounds like there's an echo. Zoom in close and you can usually nudge them into perfect sync.

Then, once you've mastered that, your next trick can be matching up several angles of a video of someone lip-syncing a song to the actual recording!

Chienworks wrote on 12/29/2004, 1:35 PM

Well, you can set the clocks on the cameras as accurately as you can push the buttons to set them. I'd guess you probably wouldn't be as accurate as 1/60th of a second though. For that matter, i don't believe Movie Studio / Vegas Studio has a way to access the datacode from the timeline. In any case, think this method would be more time consuming and less accurate than lining up the audio peaks or a video event by eye on the timeline.

MrSpeed wrote on 12/30/2004, 6:31 AM

To sync up the second camera angle I set the opacity of the top layer to 50% or so. I can then see both the main and the second camera together. At this point I drag the event to get it close then I nudge the second camera to match the main video. I too look for major motions/hand gestures to get it exact.

lukearndt wrote on 12/30/2004, 8:04 AM

Thanks for the input, guys. The sound method seems like it's the best, if it's available. I was just wondering if there was a way to sort of automatically sync the two angles, which I guess there isn't. These other methods work fine; I was just wondering if that's how it's usually done.