Video Pulsing Problem at DVinfo.net

Brian Maynard · May 27th, 2009, 05:14 PM

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

Jonathan Massey · May 27th, 2009, 06:33 PM

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.

Brian Maynard · May 27th, 2009, 07:19 PM

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

Robert Lane · May 28th, 2009, 12:10 AM

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.

Brian Maynard · May 28th, 2009, 06:04 AM

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

Robert Lane · May 28th, 2009, 08:31 AM

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.

Chad Dyle · May 31st, 2009, 12:01 PM

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")

Mitchell Lewis · June 1st, 2009, 05:00 PM

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

Robert Lane · June 1st, 2009, 06:22 PM

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.

May 27th, 2009, 05:14 PM	#1
Brian Maynard New Boot Join Date: Apr 2009 Location: Michigan Posts: 17	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

May 31st, 2009, 12:01 PM	#7
Chad Dyle Major Player Join Date: Jun 2007 Location: New Orleans, LA Posts: 410	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") __________________ www.chaddyle.com www.chaddyleproductions.com

June 1st, 2009, 05:00 PM	#8
Mitchell Lewis Trustee Join Date: Dec 2008 Location: Kennewick, WA Posts: 1,124	What format is that MOV? Quicktime can't open it on my computer. __________________ Sony EX3, Canon 5D MkII, Chrosziel Matte Box, Sachtler tripod, Steadicam Flyer, Mac Pro, Apple/Adobe software - 20 years as a local videographer/editor

May 27th, 2009, 06:33 PM	#2
Jonathan Massey Regular Crew Join Date: May 2009 Location: Amsterdam, Netherlands Posts: 28	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.

May 27th, 2009, 07:19 PM	#3
Brian Maynard New Boot Join Date: Apr 2009 Location: Michigan Posts: 17	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

May 28th, 2009, 12:10 AM	#4
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	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.

May 28th, 2009, 06:04 AM	#5
Brian Maynard New Boot Join Date: Apr 2009 Location: Michigan Posts: 17	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

May 28th, 2009, 08:31 AM	#6
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	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.

June 1st, 2009, 06:22 PM	#9
Robert Lane Go Go Godzilla Join Date: Nov 2004 Location: Scottsdale, AZ USA Posts: 2,823 Images: 15	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.