Video Pulsing Problem
 

Hi,
I am still a rookie and searched for a similar problem, but didn't see anything so I thought that I would ask.


I videotaped an event last weekend with two Canon XH A1 cameras. I taped in 3 different locations. After capturing the video to my computer, the video from the first two locations looks fine, but the video shot in the last location has a slight "pulse" every 1/2 second or so where the brightness and color changes very slightly. I can see it on the Canvas and on the Waveform scope.

Any ideas what is causing it. It was taped in 1080i60 at 29.97. First I thought that the problem was caused because the sequence was set to anamorphic DV, but when I viewed it in HDV, it had the same problem. It is not real noticeable, but I noticed it. Is it a lighting issue?

Thanks in advance for any help.

Brian

could be that you filmed in an interior and the light frequency was messing with the shot as the shutter settings were not in balance with the light source ( for example this is really noticeable when filming a computer screen).
I Always manage to avoid this problem, but perhaps a de flicker plugin can fix your image.

Hi Jonathan,
thank you for taking the time to help.

A "deflicker" plug-in? I have never heard of that, but it is a good suggestion and I will do a search and see what I can find.

Thank you.

Brian

If you shot in any auto-exposure mode it could also have been the camera making constant white-balance and exposure changes, the pulsing might be minute shutter-speed changes made by the camera - at not too uncommon issue when in auto modes.

If you could up load a few seconds of the clip we could better identify the possible cause and solution.

Hi Robert.
Thank you for taking the time to help.

The video was shot in auto-exposure mode and I think that your analysis is correct.

Assuming that is the issue, can you suggest a fix?

I see that there is a "deflicker" filter in FCP. Would that help?

I also read a post that suggested that there is an After Effects filter that might help. Any detail on that would be appreciated.

I will get some of the footage up in a little bit also.

Brian

If the problem is in fact auto-exposure "pumping" then a de-flicker filter won't help, de-flicker is actually used for a something unrelated to exposure so it wouldn't help anyway.

Unless you're in a constantly changing lighting situation that makes it impossible to track manually such as a fast-moving event (reality TV comes to mind) you should *always* be shooting in full-manual exposure. Any auto-exposure should be limited to iris (aperture) and white-balance only and shutter-speed should always remain fixed.

It would take an expensive session in a professional color-correction facility to manually correct these pumping issues frame-by-frame, so you may be stuck with the final result. Until I see a clip however I can't offer any method for masking the problem.

I just updated a post I started about this. Here is the link to a clip that I made of what is happening to me.

www.chaddyleproductions.com/video/sample.mov (Right click, "Save As")

What format is that MOV? Quicktime can't open it on my computer.

Right, that clip is either corrupt or isn't in a supported format that any Mac-based player can handle. I haven't seen a clip from Brian's issue either.