Reds are flickering/flashing... at DVinfo.net

Ben Hurst · October 19th, 2005, 04:14 PM

I just shot a spot where I shot a bunch of bright reds. Everything that is red in each shot is flashing or flickering. It is really nasty too, especially when I enhance the colors in post. Does anyone know if there is software to correct this in post or if there is a way to control it from the camera? I'm cutting on Premiere Pro with the Canopus DVstorm2 card.

Or just an explanation would be nice. I know that I should try and avoid shooting anything bright red on video, but this is ridiculous.

Justine Haupt · October 19th, 2005, 07:43 PM

See this thread: http://www.dvinfo.net/conf/showthread.php?t=52718

Richard Hunter · October 19th, 2005, 07:59 PM

Hi Ben. Strange effects I have seen with my XL2 are white balance fluctuating when shooting under fluorescent lights with the shutter speed too fast and flashing or flickering when something in the image has very fine grid-like details. So far, I haven't seen anything like you describe and I have taken shots with v-e-r-y saturated reds due to inadvertantly leaving the saturation adjusted too high.

Can you let us know what mode the camera is in? (e.g. I usually shoot in Tv mode or full manual.)

Richard

Ben Hurst · October 20th, 2005, 10:16 AM

Thanks for the thread link...the forum wouldn't let me search yesterday.

I was shooting in Tv mode in 24p. Exposure was right between 4 -5.6. I shot some of the footage with my custom settings on and some with it off and still had the flickering. I know that this is not just an XL2 problem. I had the same problem years ago with the PD-150. Anyway, I hope someone comes out with a post solution soon, or hope that the H1 won't do that.

Here is a link to the spot. I'm not sure if you'll be able to see the flashing but look for anything red.

www.fueldfilms.com/Feet.mov

Pete Bauer · October 20th, 2005, 06:12 PM

Hi Ben,

Have you verified that you see the flickering in the source 720x480 AVI file?

The QT clip is extremely compressed. All I really percieve is edge blockiness (as expected, most noticeable in diagonal lines when there is slight motion in the video) and color averaging where there were chroma gradients. I would attribute both of those effects to compression. The eye catches motion in the bright red better than other colors; that would be true even if the motion only exists because of artifacting, rather than actual motion in the higher resolution source footage.

When I looked for the same migratory blotchy look (color averaging) and the edge artifacts in the other colors, I saw them. A good example is the bright blue plastic chair on the right of the image just over half way through. Where natural reflections cause the imaged color to lighten, you can see a blurred, shimmering effect as the compression changes a bit frame to frame.

That said, there is a known 24p anomaly in PPro that causes strobing in super-white images. I don't know if oversaturation in one color could do the same. See: This Post

I'm not saying it ain't there; just that I don't think I'm seeing what you're seeing, or at least interpreting it very differently. So I guess step one is to view a 30p or 60i source AVI clip and see if whatever you're seeing in the MOV is actually in the source. If you can post a short MS DV AVI from your project, that would be great.

Oh, another quick thing to try would be to add a Broadcast Colors filter before rendering and see if that changes anything.

Cheers.

Ben Hurst · October 22nd, 2005, 07:56 PM

Thanks Pete. I'll look into a few of those things on Monday!
There is flickering in the original footage. I applied a few filters to boost colors and the flickering worsened. The flickering is kind of hard to see in the small quicktime. I'll see if I can't post a different version.

Thanks

October 19th, 2005, 04:14 PM	#1
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	Reds are flickering/flashing... I just shot a spot where I shot a bunch of bright reds. Everything that is red in each shot is flashing or flickering. It is really nasty too, especially when I enhance the colors in post. Does anyone know if there is software to correct this in post or if there is a way to control it from the camera? I'm cutting on Premiere Pro with the Canopus DVstorm2 card. Or just an explanation would be nice. I know that I should try and avoid shooting anything bright red on video, but this is ridiculous.

October 19th, 2005, 07:43 PM	#2
Justine Haupt Major Player Join Date: Oct 2005 Location: Long Island, NY Posts: 208	See this thread: http://www.dvinfo.net/conf/showthread.php?t=52718 __________________ ~Justine "We are the music makers, and we are the dreamers of dreams" -Arthur O'Shaunessey (as quoted by Willy Wonka)

October 20th, 2005, 06:12 PM	#5
Pete Bauer Wrangler Join Date: May 2003 Location: Eagle River, AK Posts: 4,100	Hi Ben, Have you verified that you see the flickering in the source 720x480 AVI file? The QT clip is extremely compressed. All I really percieve is edge blockiness (as expected, most noticeable in diagonal lines when there is slight motion in the video) and color averaging where there were chroma gradients. I would attribute both of those effects to compression. The eye catches motion in the bright red better than other colors; that would be true even if the motion only exists because of artifacting, rather than actual motion in the higher resolution source footage. When I looked for the same migratory blotchy look (color averaging) and the edge artifacts in the other colors, I saw them. A good example is the bright blue plastic chair on the right of the image just over half way through. Where natural reflections cause the imaged color to lighten, you can see a blurred, shimmering effect as the compression changes a bit frame to frame. That said, there is a known 24p anomaly in PPro that causes strobing in super-white images. I don't know if oversaturation in one color could do the same. See: This Post I'm not saying it ain't there; just that I don't think I'm seeing what you're seeing, or at least interpreting it very differently. So I guess step one is to view a 30p or 60i source AVI clip and see if whatever you're seeing in the MOV is actually in the source. If you can post a short MS DV AVI from your project, that would be great. Oh, another quick thing to try would be to add a Broadcast Colors filter before rendering and see if that changes anything. Cheers. __________________ Pete Bauer The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. Albert Einstein Trying to solve a DV mystery? You may find the answer behind the SEARCH function ... or be able to join a discussion already in progress!

October 19th, 2005, 07:59 PM	#3
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Hi Ben. Strange effects I have seen with my XL2 are white balance fluctuating when shooting under fluorescent lights with the shutter speed too fast and flashing or flickering when something in the image has very fine grid-like details. So far, I haven't seen anything like you describe and I have taken shots with v-e-r-y saturated reds due to inadvertantly leaving the saturation adjusted too high. Can you let us know what mode the camera is in? (e.g. I usually shoot in Tv mode or full manual.) Richard

October 20th, 2005, 10:16 AM	#4
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	Thanks for the thread link...the forum wouldn't let me search yesterday. I was shooting in Tv mode in 24p. Exposure was right between 4 -5.6. I shot some of the footage with my custom settings on and some with it off and still had the flickering. I know that this is not just an XL2 problem. I had the same problem years ago with the PD-150. Anyway, I hope someone comes out with a post solution soon, or hope that the H1 won't do that. Here is a link to the spot. I'm not sure if you'll be able to see the flashing but look for anything red. www.fueldfilms.com/Feet.mov

October 22nd, 2005, 07:56 PM	#6
Ben Hurst New Boot Join Date: Aug 2005 Location: Austin, TX Posts: 22	Thanks Pete. I'll look into a few of those things on Monday! There is flickering in the original footage. I applied a few filters to boost colors and the flickering worsened. The flickering is kind of hard to see in the small quicktime. I'll see if I can't post a different version. Thanks