Camcorder w/ DAW

Infinite5ths wrote on 1/18/2006, 9:07 AM

NOTE: I did search the forum, and found some results that relate to this. However, there were quotes like: "If you are initially in synch, but maybe out an hour later, there are various tools in Vegas - Split, stretch (Ctrl drag edge), to keep things lined up. " (Source thread: http://www.sonymediasoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=304410)

Is this common? Should I expect to have to touch up the timing? Even small timing issues bother me greatly. I have commercial music DVDs (originally recorded on laser disc) that have timing sync issues - i.e. the violinist's bow is CLEARLY not with the audio. I don't consider that acceptable. But then, it would be VERRRY time consuming to try to fix those kinds of issues all through a full length concert recording.

Thoughts?

ORIGINAL POST:
Hey folks!

Question: How feasible is it to syncronize audio from a DAW (Vegas, Sonar 4 or my Yamaha HDD recorder) with video from a consumer camcorder like the Panasonic GS250? I know the software portion of putting the two in sync should be easy. I'm wondering about drift in the camcorder timing. This consumer cam doesn't have SMPTE ouput for alignment/sync purposes.

For example: I plan to record audio into my DAW system (I have the three options listed above) with my high end audio mics, and simultaneously record audio & video on the camcorder. I would like to be able to record a couple clicks, beeps, etc. at the beginning and then line up the DAW audio tracks with the camcorder audio tracks using those clicks, beeps, etc. later. Then I can delete the camcorder audio track. Do I risk having video and audio out of sync late in the recording or are the consumer MiniDV cams stable enough to avoid A/V drift?

I would like to do some music DVD work with this, but will do a lengthy recording test before I do any live or for-pay work. ...that is, unless somebody responds here and says "You'd be wasting your time trying to do that with this kind of equipment".
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Mike

Comments

Infinite5ths wrote on 1/18/2006, 9:50 AM

I think this quote partially answers my question. I'll have to run some actual tests to determine if the small drifts bother me.

Source Thread: http://www.sonymediasoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=299469

Post By: John_Cline

<QUOTE>
Finally, there is another theoretical issue and that is locked vs unlocked audio. DVCAM records "locked audio" where there is an equal number of audio samples recorded per frame of video. This ensures absolute audio/video sync. DV records "unlocked audio" which is kind of like having a dog on a leash, the dog (audio) can get a little ahead or a little behind, but it can never stray very far in either direction, so, for all practical purposes, the audio stays in sync. While locked vs unlocked is a consideration, in the real world, it's pretty much a non-issue. After all, we're talking about it drifting a few samples either way, not frames of drift.
<END QUOTE>

From this, I take it that the overall sync from beginning to end should be fine, as long as I record on the DAW with the same sample rate as the camcorder. (I suppose it might be OK even if I used a different sample rate...assuming the DAW/Vegas did the timing re-calculations correctly in post.) The key seems to be that there is a consistent (or - with MiniDV - semi consistent) number of samples/frame.
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Mike

rs170a wrote on 1/18/2006, 10:32 AM

Mike, my coworker did exactly this over the Christmas holidays. He was handed several tapes (shot on 2 GL2s) and files from a DAW (Cubase, Sonar??). The on camera mics were used as a reference but the DAW was recording (as I recall) 8 separate channels from the (2 or 3-man ) band.
Not only did he not have any sync problems (which are easily corrected in Vegas anyway), he also did it as a 5.1 mix :-)

Mike

Infinite5ths wrote on 1/18/2006, 10:38 AM

Wonderful! Thanks for the confirmation.

I love digital....always have, still do. :-]
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Mike

PeterWright wrote on 1/18/2006, 7:20 PM

Rather than delete the camcorder audio, better to Mute it, so it's still there for reference purposes.

Infinite5ths wrote on 1/19/2006, 9:02 AM

Yes...you are right. That is one of the chief joys of multitrack DAWs -- INSTANT but NON-DESTRUCTIVE edits. :-]
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Mike

farss wrote on 1/19/2006, 12:11 PM

One issue I've noticed with multicam shoots without genlock is you can have at least a half frame error. Now that might not sound like much, certainly very few people can pick less than about 2 frame errors in A/V sync. Except do a dissolve between the two cams on the same subject and if that subject is moving quickly it really sticks out.
Bob.

Infinite5ths wrote on 1/19/2006, 1:13 PM

Bob,

Thanks for the info. However, at this point, I am not unfortunate (or fortunate -- as you choose to see it) enough to have to deal with multi-cam shoots. Some day...

Just out of curiousity...what anomoly in a multi-cam video environment could be most closely compared with mic phasing issues (comb filtering, etc.)? In other words: multi-track/multi-mic engineers make a BIG deal out of proper phasing & isolation. What factors in multi-cam video get the same kind of attention?
--
Mike