multicam edits - tips for syncing up audio?

ken c wrote on 5/28/2006, 9:32 AM
Anyone have any quick tips for syncing up audio for non-smpte coded 3-cam shoots?

All I can do is, expand the timeline and look for similar waveform peaks n patterns, and in the video feeds, look for stand-out type activities (eg a hand gesture or other visual cues) ... and then use M/to mark and then manually, tediously line up each cams' a/v in vegas' timeline... arrgghh :p

I've got a big 2-day seminar, 12+ hours of 3-cam video footage to sync up .. it's a lotta work (though ultimate s makes the multicam part of it easy, Once I get the 3 cams synced up)

I think for future video shoots I'll either a) invest in smpte-synced cams or b) use clapper boards regularly during the event, so I can sync it in post easier..

one challenge too is, with my b-cam shooters' footage, he stopped/paused the tape, and did it on a regular camcorder, so there's a lot of "chunks" of video vs one long stream, so I can't just do a start-of-shoot lineup ... I've gotta re-align each chunk of b cam footage w/the main a-cam timeline... listening for audio peaks, lining em up...

appreciate any tips ... this is new to me ..

here's a screencap of part of the timeline:

http://www.sitefomercials.com/vegastimelineb.gif


ken

Comments

DavidMcKnight wrote on 5/28/2006, 9:48 AM
You're correct about finding areas in the wav that are similar, peaks of applause, etc. You can also look for flashes in the video to get the same frame.

re: audio, the way I do it is pan the two audio tracks hard left and hard right. I click select the track I want to move to get lined up and use the 1 and 3 numeric keypad keys to move the track a frame at a time. You need to be stretched out some to make sure you're only moving a frame with each click. Your audio will have a delay from speaker to speaker that gets shorter and shorter as you get closer, and when you have no delay you should be lined up properly.

Once two are lined up, use the G key to group them together, and add your next track.

<edit> As Spot points out below, it's better to loop a section while you're doing this.
ken c wrote on 5/28/2006, 9:50 AM
hey David, thanks - I never would've thought of that .. that's a great tip - thanks! much better than manually muting/unmuting each audio track .. that'll save time .. appreciate it - smart tip!

ken
GlennChan wrote on 5/28/2006, 12:22 PM
Syncing via video:
It could help you to bring a still camera with flash along. The flash will show up on all cameras and happens for only 1 frame or field, making it easy to sync things visually. (This is what David is suggesting really.)


Syncing via audio:
Shift + up arrow on your keyboard will make the waveforms easier to see sometimes. You can also adjust the audio track heights bigger. Crtl Shift up/down arrow is the shortcut if I remember correctly.

Syncing via timecode:
Some (but not all) cameras support time of day timecode. If you set the time very close to one another, you should theoretically be able to use the timecode to get close. And then use another method to get perfect sync. I haven't tried this.

On high end gear you can jam sync timecode so you'd just match up the timecode and it would be in perfect sync, as long as the clocks in the cameras don't drift that much (in which case, they might be a frame off).
Spot|DSE wrote on 5/28/2006, 1:11 PM
my method is to create a loop of an area that contains percussives and sibilance, and then slide two tracks using the 4/6 keys, til I hear no flam or delay. This lets me know I've got two in sync. Then I mute track 2, unmute track 3 and repeat until I've got all tracks in sync. Unmuting them all, I should have no delay and virtually no flam in the audio. Then I re-mute the non-master tracks and edit away.
I group if it's just free running cam, or leave ungrouped if I've got multiple clips to work with.
ken c wrote on 5/29/2006, 5:59 AM
appreciate those tips too... nice idea Glenn re using shift/arrow to change size of audio track, hadn't thought of that... agree that should make it easier to see waveform peaks ... and flashes, I like that, I can have someone take photos now and then, and use those as sync points.. great idea..

and thanks Douglas too re the looping percussive idea, I'll try that out as well... til the flam/double tap/delay sound disappears, to get it in sync. (btw I just got your "Voices" cd, it's excellent!)

thanks all,

ken
Steve Mann wrote on 6/5/2006, 8:33 AM
I go one step further than DSE - Fade one track to 100% Left, and the other to 100% Right and the off-synch echo will be much more pronounced and easier to hear. When you hit the sync point, it's like walking out of a concert hall into a closet.

Steve M.