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Hey All -

I've been using my Canopus ADVC-100 with my G5 Dual 2.3 for about a year now. Pretty happy with it for the most part, although I've never been able to get the video compensation completely correct...

I've had it set to as high as 18 frames in order to have the video sync with the dialog, but having it this high produces a pretty ugly problem. The video is in fact ahead of my DP sequence. Say I want a cue to come in right on a cut. When I have the DP sequence still framed, the cut may be at the downbeat, but when I actually play the sequence and the video runs, the music ends up being early somehow. I'm not quite sure why this happens. When it's set to 5 frames the still frame and the running video seem to lock up - but then the audio on the movie doesn't! (Cat and Mouse anyone?!)

So I guess my question is this. I've figured out that 5 frames is about right in my situation. If this is the case, then why wouldn't the dialog in the quicktime movie line up? (the audio is consistently ahead of the video.) I'm going audio out via the optical port on my G5 which if anything would introduce more latency, right? I'm at 44.1k on my digital mixer - could that be it?

Thanks for any insights - I know copying the audio to the sequence is an option, but I'm dealing with some pretty hefty quicktimes, and to do that for each cue isn't really an option for me.

Thanks again!

P.S. Also anybody notice that when you play in DP the video scrubs ahead for the first few seconds, this is it catching up, I take it?

I'm not a video guy, but I believe 48k is where you want to be with audio for video. Are you digital all the way into your mixer? If so, then yes, your probably right in thinking that 44.1 could be your problem.

Hopefully someone who does this for a living will chime in...

Hmmm sounds fishy to me. I use the ADVC 100 everyday. The compensation never gets even up to 5 frames. [which would be a lot!].
Why are you taking the audio direct out if the mac? That usually never works - your trying to clock to the Mac/Qt and DP audio at the same time. Not a good plan. Bring the audio from the QT into DP. Come out your audio interface with it and make sure all the sample rates agree.

All pro digital audio for video in NTSC land as well as HD is at 48K. Get everything on that page as well as your mixer and you should be fine.

Good luck with your project.

Thanks for your replies. A few thoughts. I have a powercore firewire on the same computer, but have it a firewire PCI card, not directly connected to the G5.

I use the audio output of the G5 because it goes into a different input on my digital mixer. Copying the movie audio to the chunk is just too troublesome for me for a number of reasons.

I've been able to sync up things well by having a 5 fram offset, and then (this is strange) delayinng the audio in the quicktime 8 frames. (I do this in Quicktime Pro.)

Everything seems to sync up now - just a bizarro work around!

Cheers!

5 frames would seem about right, considering that the movie sync offset in Pro Tools for the Canopus is 22 quarter frames. I've never used it with DP, so it's possible that this could be different, but unlikely. Outputting through firewire will always be "fishy" just because of the real-time compression/decompression happening. If you can learn to deal with the inconsistencies, then it's a nice/cheap option for external video monitoring, but not precise. You'd have better luck with monitoring the video on a second display (extended desktop). Always keep you audio at 48k when working with video material; it's the standard. And using the Mac's output is a pretty bad idea for various reasons. Are you using an interface as well?

-Will

5 to 6 frames seems about right for the Firewire latency, are you using QT7? if so there is an issue with DP and audio sync with QT7.

Are you copying your movie audio to DP?

HTH

Randy Knaub