Flickering / strobing in video?

[angelah100]

I downloaded a trial version of Premiere Pro CS6 because it had a bit better 'green screen' capability than Elements and I needed it for a specific project. The software is great, and I'm done with the video except that during playback and also on the final ISO file there is a weird flickering/ strobing effect, especially on the clips where I've applied the Ultra Key. It's almost as if the Matte is flickering. I've not had any problems with the exact same clips in Premiere Elements 11. The clips are from a Panasonic TM700, HD video but 29.97fps not 60fps. I also signed up for one month of this software 'in the cloud' on the off chance that it was due to it being a trial, but that made no difference. I searched some of the community forums but only found a reference to playback flickering when there was more than one monitor in use, and that doesn't apply to me. Drivers are all up to date. Can't imagine what would cause flickering in Pro version and not Elements!

On further experimentation, I can tell that the strobing is not random, I can actually freeze on the frame where the background (which should be masked out with Ultra Key) suddenly appears albeit in a different color. I think it might have something to do with the Autocolor, which is applied before Ultra Key. I'm in the process of adding some temporal smoothing to see if that helps. If I eliminate the Autocolor, then I have to redo all my Ultra Key color settings (which I don't have time to do).

I have to have the dVD done by tomorrow and would love any help, if anyone happens to be online here on a Sun night.

Thanks
Angela

Dell XPS 435T 64 bit
Intel i7 CPU 920 @ 2.67GH 2.67GHz
9 GB RAM

[Bob]

I haven't seen that problem with Ultra Keyer before. I've heard of similar glitchy problems when using gpu accelleration. You might try turning gpu accelleration off in the project settings by selecting software rendering and see if that makes a difference.

[angelah100]

where do I find gpu acceleration? I can't seem to find it in order to turn it off.....

[Bob]

From the menu: Project>Project Settings>General. At the top of the Project Settings panel, for the renderer, select Mercury Playback Engine Software Only.

gpuOpts.jpg

[angelah100]

That dropdown box is disabled for some reason, but is already listed as software only. I've applied temporal smoothing to some of the clips and I think it helped a bit, the flashes are still there but less intense.

[Bob]

If it's disabled, you aren't using gpu accelleration. That rules out a GPU glitch.

I don't know what to suggest next. I've not seen anything like this with Ultra Keyer. Have you tried using one of the other keyers (chroma key or color key, for example)?