MAJOR Vegas timecode syncing issue

cchoy wrote on 12/21/2006, 10:43 AM
I just hooked up Vegas to my mixing board via USB midi, and noticed a BIG problem. When set to 29.97 ND, Vegas drifts futher and further off as the timeline progresses. I do not get this problem with any other frame rate (though there is a 2 or 3 frame discrepency.)

Although the clock on Vegas says that it is outputting correctly, I have matched up with 3 different devices: The Yamaha DM2000, the SR15 Timecode distripalyzer, and the Skotel TC generator. Each one shows the same thing: the timecode displayed in Vegas and the TC that it is actually sending out gets more and more out of sync as time goes on.

Unless I'm overlooking something, this is a MAJOR problem, as I need to be able to stay in sync. Afterall, isn't that what the sync function is for?

Comments

pwppch wrote on 12/21/2006, 2:17 PM
Vegas does not chase lock to time code. It triggers only.

The only thing I can suggest is that make sure your audio hardware and timecode source are locked to a common word clock, otherwise you will get drift due to different sample clocks.

Peter
cchoy wrote on 12/22/2006, 8:25 AM
Peter--

I think I phrased myself incorrectly last time. This is not a word clock issue. The entire studio (including Vegas) is hooked up to a common sync box running at 48KHz. The problem is with Vegas generating faulty Midi Time Code (MTC).

I am using Vegas to generate MTC, and sending that MTC through a JL Cooper Box to convert it to SMPTE. When I read that SMPTE timecode on other devices, it reads differenlty than Vegas does when using the 29.97 Non Drop Function.

The way that I know that it is not the fault of the JL Cooper PPS2 is that I have also tried sending MTC directly out from Vegas. When set at 29.97 NON DROP, Vegas displays a different timecode than the devices that it is sending to. The difference gets progressively worse as the timeline gets longer and longer.

Hope this made more sense.
ultrafinriz wrote on 12/22/2006, 1:05 PM
What happens when you slave vegas to something else? I've always used my DAWs as a tc slave to the VTR. I wonder if you have the same inconsistencies at 29.97 opposed to the other rates.

Best,

Jesse
cchoy wrote on 1/1/2007, 10:25 AM
When I slave Vegas it is, as Peter said, triggering only, not chasing, and it works fine. When I use Vegas as a master, THAT is when the problem occurs. The problem ONLY occurs at 29.97 non drop rate.

ultrafinriz wrote on 1/2/2007, 7:38 PM
Any chance that you've got some sort of TC feedback loop? It seems like it would be possible to have vegas set to generate AND chase timecode which could become a real mess. Just a thought...
Jesse
cchoy wrote on 1/3/2007, 11:02 AM
No feedback loop.... I checked out for that.

thanks though...
H2000 wrote on 1/6/2007, 5:21 PM
I have had very bad experience trying to get accurate MIDI timecode out of USB MIDI devices. You may want to try a PCI based MIDI card. Or, possibly there is a way to prioritize the USB interrupts in the OS. Also, check to see if something else is sharing the USB port interrupt.
cchoy wrote on 1/9/2007, 12:50 PM
Still having the same problem.
The drift is consistently off, (logorithmically), and ONLY occurs when VEGAS is generating MTC. ONLY 29.97 NON-DROP Frame is giving me the issue, but this is a problem, as most on set things are being stamped in this format...
RonA wrote on 1/17/2007, 3:35 PM
You say the problem is only on 29,97. This means that you did a test on 25EBU and encountered no problems?
ultrafinriz wrote on 1/19/2007, 6:40 AM
I think that's what he's tried so far. Not much else to try. I guess it doesn't work at 29.97 generating from Vegas.

Where'd Peter go??

Jesse
cchoy wrote on 2/12/2007, 5:06 PM
Any word on what's going on? Anybody else try to duplicate the problem?