Flicker on video when using camera-movements or position-movements

[Tony Kloiber]

Try putting all your clips side by side in the (standard PAL 720×576) comp, make a null, parent all the clips to the null and keyframe the null.

TonyTony

[Austin Ray]

Hi!

Thanks for the tip. Unfortunately it didnt make the flickering go away. Infact, right now, no matter what I do…it does flicker when moving videoclips pass the screen. As long as the video is standing at the same position, everything is fine.

Can this have anything to do with Interlacing, or something else?

[Steve Roberts]

There is more than one type of flicker, jitter, or judder, as we have seen. 🙂

In my personal vocabulary:

1. “flicker” is what you see when you have thin (1-pixel or so) lines in your image. As these lines move between scanlines or fields on a broadcast monitor, they will flicker. This can be solved by applying a vertical blur (fast, gaussian or directional) to the image. If the image is at about 100% scale, 1-pixel blur should be fine. If the image is scaled down, you may need to apply more blur. Check the broadcast monitor and you should see the flicker go away.

2. “Jitter” is seen on a broadcast monitor when your fields are reversed. The object jitters back and forth very quickly. The frequency is 60 times per second (NTSC) and the amplitude (length of jitter) is proportional to the speed of the object’s motion on screen. You’ll only see this if you’ve interpreted footage incorrectly, or placed 480-high footage in a 486-high comp with an odd number of pixels above the footage. If you’re dealing with imported clips, this may be your problem. You should separate fields when importing the footage, or re-interpret the footage (file>interpret footage>main) and separate fields. Most stuff nowadays is lower field first, but not necessarily. By the way, you shouldn’t separate fields if the footage was shot progressive. So try separating fields, maybe with a different field order. (not “field dominance”, which is something different, and often incorrectly used to mean “field order”)

3. “judder” was described in earlier posts, or found by searching. It’s the phenonmenon when our brains start to actually see the discrete frames of motion. It is very apparent with frame-rendered footage. There’s no technical trick to fix it, but field rendering can help. Otherwise you have to change the animation by mixing up things to distract the eye. Or ask the client — they might not mind. Judder shows up all the tiem in films — remember that Stella Artois spot when the soldiers come home from the front? There was a horrible judder in the pan around the village square off the top of the spot.

So try re-interpreting the footage and separating fields.