CALIBRATION 2 – SYNC!

Following up on the LINE YOUR ROOM UP post a while ago, for this post I have called on a brilliant dialogue/ADR Supervising Sound Editor & friend Ray Beentjes

“I work with film dialog a lot and started getting upset at how bad the Quicktime Pictures seemed to be running in ProTools. I was using a good Dual Processor G4 Macintosh and an Aurora Igniter video card. Previously we had got great results from OS 9 and the Aurora Fuse video card but it wouldn’t work in OSX. I had splashed out good $$ on the (Digi Recommended) appropriate gear but the setup was not working well.

A chap by the name of Richard Fairbanks who pops up on the Digidesign User Conference from time to time had started developing a device called “Syncheck” and I bought one.

It’s a simple enough device that allows you to measure the sync difference between Picture and Sound. It achieves this by the user playing a ProTools Session containing a Quicktime movie with white flash frames and associated audio file which has beeps aligned to the frame edges of the white flashes. As you can see from the picture the device has a simple readout that tells you if the picture is ahead or behind sound and how much. You simply adjust the Movie offset in quarter frames and hey presto your pictures are running in sync with your sound. The delay shows up as an led bar graph column. Less dots… less delay.

So you might say, big deal. I checked out my rig. Oh dear, my $1500 Igniter card played pictures anywhere from 1/4 to a frame late, randomly. No wonder it was hard to judge sync. An Aurora fuse card on an older OS9 Mac gave about 1/4 frame delay in picture. Not so bad and it didn’t drift.

I ditched the Igniter card and moved to a G5 Macintosh and started using a $50 DVI to Video adapter running of my dual head video card that came with the G5. It has a 1/4->1/2 frame delay too but no drift in that delay. A 2 quarter-frame offset is all that’s needed and it runs better than my Igniter card any day. Note that this offset was calculated using a standard Sony 29″ CRT television set.

Richard Fairbank’s company can be found on the web at :-

www.syncheck.com

He’s tested a number of devices and posted the results on his site.

Since that time I moved on to a new Apple MacPro Dual 2.66 Ghz Intel based machine which came equipped with an NVidia 7300 Dual-link DVI video card. The performance of these machines is such that it does not tax the CPU of the machine to play fairly hi-res Quicktime movies even whilst running huge ProTools sessions. I started to enjoy the crispness of Quicktime movies played out on a second DVI LCD monitor. They are also ideal for displaying true 24FPS movies without any of the flickery images you sometimes see when using a CRT television monitor. Currently I’m running a Dell 30″ LCD monitor for ProTools with an Apple Cinema display reserved for picture playback but I’ve been spoilt by the big-monitor bug and so another 30″ monitor is on the shopping list. The quality of these new huge LCD’s is amazing and I see no reason to go back to television sets again. Another colleague uses a 30″ domestic LCD TV set that has a DVI input and this is giving him great results. Once again, check the sync offset with a Syncheck.

I seriously challenge anyone who works in SoundPost to check it out. Unless you’ve got the Digi Mojo Box then YOUR PROTOOLS QUICKTIME MOVIES ARE NOT IN SYNC unless you’ve running some kind of offset in the Movie offset window. Even if you are using Mojo you need to check the video latency introduced by your monitor.

Picture delay is like latency in Digital Audio. It’s always there….. you just have to know how much.. and correct for it. Most folks have a different opinion about sync and it’s nice to have a device to actually measure it. Trying to convince people that this adjustment needs to be made is difficult as it can often seem like you are being critical of their ability to judge sync. But the results after sync correction speak for themselves.

Remember if you are using an Plasma, LCD TV or 100 HZ widescreen CRT TV set as a monitor you WILL have a delay induced by the latency inherent in these devices. This will delay the picture you are viewing by up to 2 or 3 frames!

Ray

2 Responses to CALIBRATION 2 – SYNC!

  1. It’s on my wishlist!

    MM

  2. Pingback: Designing Sound » More than 50 Articles/Tutorials about Sound Design, Recording and more, Plus Wooshes Sound Design

Leave a Reply

Please use your real name instead of you company name or keyword spam.