FireWire Video Latency Variations

sean@oregonsound.com wrote on 2/11/2008, 6:04 PM

Hi all. I presume many here use a Canopus converter to get video up on their external monitors. In searching out a sync issue I was having between my rendered audio files and the video editor's system, I bought a Syncheck II and was surprised to discover that there is a 2 frame latency difference between 29.97 and 23.976. Can anyone else verify that they have to adjust their sync offset differently for different frame rates? If true, it would explain my sync problem and I'll be able to rest easily once again. For awhile, anyway.

Comments

sean@oregonsound.com wrote on 2/13/2008, 10:29 AM

So am I really the only person here who sends DV video out via FireWire and also works at multiple frame rates? Surprising!

jazzmaster wrote on 2/13/2008, 11:29 AM

I have a canopus and find that when I hook up the 4-pin Fire Wire from my camera into the canopus and out to my computer's 6-pin, there is a sync problem. However, if I input the 4-pin directly into the computer's 4-pin slot, there is no sync problem. With the canopus, I get a jump at the beginning of each capture segment. Without the canopus, no jump. It's in sync. Why do I use the canopus? Because sometimes Vegas does not recognize my 4-pin direct connection and I don't want to fiddle with it. I don't know if this helps, but it's my experience.
Burt

bob ripperden wrote on 2/14/2008, 9:03 AM

I too have a sync problem.. I went from a canopus to a sony digital camera for the dv conversion but it did not help, still the same, out of sync....I'm thinking of going back to final cut pro after wasting lots and lots of time with the many problems with vegas pro 8

rs170a wrote on 2/14/2008, 9:31 AM

Sean, it's not necessarily the fault of the Canpous box.
Reading this thread reminded me a a discussion about this same issue on the RAMPS forum (rec.arts.movies.production.sound).
In that discussion was a link to a Audio/video sync discussion on Adam Wilt's site.
BTW, 2 frames seems to be the common denominator :-(

Mike

sean@oregonsound.com wrote on 2/14/2008, 11:58 AM

Thanks for the reply---I'll check out that other discussion. Actually, I never assumed there was a problem with the Canopus. DV conversion creates latency in all converters, to the best of my knowledge. My only question is whether or not a 2 frame latency difference between framerates is normal, or just a quirk of my system. A poster on Gearslutz said it was very plausible, particularly if a system uses different codecs for different framerates.