Could wiggle fix the light flickering

[Filip Vandueren]

wiggle won’t help you because it is random.

If you think you can fix it with repeating keyframes, then set a few keyframes and use the loopOut(“cycle”,0); expression to repeat those keyframes indefinetely.

IN theory the “Color Stabilizer” effect could help by doing the brighness adjustment work for you. But I’ve never had truly useable results from this.

And if all else fails, you may have to use the echo-effect to blend two frames together using the ‘Maximum’ operator.

[Abdo Abouzeid]

The Loop cycle fixed it 😀 but i got lucky cuz the stupid light had a pattern of 2:1 flickering, if it was random i would be dead now 🙂 thanks alot Filip 🙂 you saved my butt.. i guess i will be using this forum way more than i thought 🙂

[Jon Geddes]

I just came up with this expression that might work for you:

• Add a Brightness & Contrast Effect to your footage
• Add a Point Control to your footage
• Add a Slider Control to your footage

Drag the point of the point control to a good consistent part of the green screen where there are no shadows or moving areas.

Move your mouse over the green screen for that point and look in the info panel to see the green color of it. I’m guessing it will be somewhere around 116 (depending on how you lit your screen)?

Now adjust the slider control to equal that number. (You may want to tweak this a little later)

Then apply this expression to the brightness control:

NormalGreen = effect("Slider Control")("Slider");
samplePoint = effect("Point Control")("Point");
sampleRadius = [5,5];
sampledColor_8bpc = 255 * sampleImage(samplePoint, sampleRadius);
(sampledColor_8bpc[1]-NormalGreen)*-1;

Jon Geddes
http://www.precomposed.com

[Abdo Abouzeid]

Hey Jon.. thanks alot for the reply =), i tried what you suggested but it didn’t work, the whole footage (greenscreen, and actor) became brighter, and the brightness value was stuck on 100 through out the footage. the light that was causing the problem was on the actor only, but the green screen lighting was nice and consistent.. it was about 112, so i guess it was very close to what u suggested. i would be happy if you have more suggestions, i was compromising by making the background flicker like the actor just for the sake of the composition, but i would rather cancel both of the flickering.

Thanks alot in advance =)

[Jon Geddes]

The script I wrote doesn’t necessarily have to be used on the green screen. It can be used on any part that is pretty consistent throughout the shot, but does have the flickering. You could even use the motion tracker to track the point of the color sampler to an object that is moving. You might also need to adjust the sample radius as well. I tested it out and it worked perfectly for me (brightness was not stuck at 100).

It should be ok if the background flickers after you remove the flicker from the actor, since the background will be keyed out anyways. You will have to adjust the key so it also keys out the brighter frames.

Jon Geddes
http://www.precomposed.com