Why does my footage flicker? at DVinfo.net

Brian Patterson · June 22nd, 2004, 06:42 PM

I'm noticing that my camera's footage flickers slightly (some background stuff like leaves on branches) when I slow it down. Is this something I can fix in post by putting a flicker filter or de-interlace filter on it? I don't like applying those filters regularly because as we all know it degenerates the quality a bit.

Why is this happening and is the best way to fix it in my editing program now? If so, which is the best way?

(No, my camera has not been dropped!)

Oh yeah, I'm shooting with a VX2000

Boyd Ostroff · June 22nd, 2004, 07:31 PM

Hi Brian. You might have a look at a similar discussion in the FCP forum. But actually it sounds like you may be viewing artifacts of the extreme data compression used by DV. It's especially noticeable in details like leaves and branches.

You would need to tell us a lot more about your camera settings, software and how you're slowing the footage down if you want a specific suggestion for improving results. I've shot footage with my VX-2000, slowed it down in FCP and the results were pretty much what I expected.

Brian Patterson · June 22nd, 2004, 08:00 PM

I was shooting outdoors on a partly cloudy day. Auto exposure, manual focus (but properly focussed!). It doesn't show up as much on a larger tv. It's most noticeable on my little 14" flatscreen (even though the 14" flatscreen is brand new).

I'm editing with Final Cut Express 1.0.1. I'm slowing the footage down by changing the speed from 100% to 75 or 50%. I'm using RCA cables to connect my cam to my tv. I DO notice that on my little 14" tv sometimes graphics and titles from tv shows give an audio "scratching" noise when they come on the screen...could it be that my tv is too sharp or something?

What do you mean by "the results were pretty much what I expected" when slowing footage down.

Thanks for your reply, I look forward to seeing if I can figure this problem out...

Boyd Ostroff · June 22nd, 2004, 08:26 PM

OK, that's helpful. Personally I find all consumer TV's to be way over-sharpened and turn it down to the minimum. This is especially true of LCD panels, if that's what you mean by "flat screen". I have a Sony 17" widescreen LCD video monitor, and when I first plugged my camera into it was really upset by the image. Reducing the sharpness to the minimum made a huge difference. For one thing, the oversharpening really accentuates any noise in the picture. But if you mean a 14" consumer flat screen CRT TV, all of those that I've owned (including a Sony WEGA) had really poor image quality and I gave up using them with FCP. Connecting a TV with RCA composite video is also noticeably worse than s-video and very possibly contributes to the problem, however I've never seen a little 14" CRT TV with s-video in. You might try exporting your slo-mo sequence back to tape, then take your camera to a store where you can hook it up to a better monitor with an s-video cable and see if the problem goes away.

If you're shooting in automatic mode then of course you aren't performing a controlled experiment since you don't know what shutter speed the camera is choosing. Under bright conditions it could be raising that as high as 1/1000 sec. You can look at the data code on your tape by pressing the button under the LCD screen and that will tell you the shutter speed. High shutter speeds can cause an effect like you mention, especially when slowed down.

Try using manual mode (silver switch in the center position between auto-lock and hold). Now press the shutter speed button and make sure it reads 60. Press the exposure button and manually adjust the iris properly; if you can't prevent overexposure under bright conditions use the ND filter. Now see if your results look better in FCE. You should also choose the "frame blending" option or you may very well see problems like you describe.

"Pretty much what I expected" meant that when you're only capturing 30 full images per second your raw data is limited and you can only slow it down so far. Special cameras are used to shoot high quality slow motion. But you should be able to get a pretty nice 50% speed reduction.

June 22nd, 2004, 06:42 PM	#1
Brian Patterson Regular Crew Join Date: May 2003 Posts: 51	Why does my footage flicker? I'm noticing that my camera's footage flickers slightly (some background stuff like leaves on branches) when I slow it down. Is this something I can fix in post by putting a flicker filter or de-interlace filter on it? I don't like applying those filters regularly because as we all know it degenerates the quality a bit. Why is this happening and is the best way to fix it in my editing program now? If so, which is the best way? (No, my camera has not been dropped!) Oh yeah, I'm shooting with a VX2000

June 22nd, 2004, 07:31 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Hi Brian. You might have a look at a similar discussion in the FCP forum. But actually it sounds like you may be viewing artifacts of the extreme data compression used by DV. It's especially noticeable in details like leaves and branches. You would need to tell us a lot more about your camera settings, software and how you're slowing the footage down if you want a specific suggestion for improving results. I've shot footage with my VX-2000, slowed it down in FCP and the results were pretty much what I expected.

June 22nd, 2004, 08:00 PM	#3
Brian Patterson Regular Crew Join Date: May 2003 Posts: 51	I was shooting outdoors on a partly cloudy day. Auto exposure, manual focus (but properly focussed!). It doesn't show up as much on a larger tv. It's most noticeable on my little 14" flatscreen (even though the 14" flatscreen is brand new). I'm editing with Final Cut Express 1.0.1. I'm slowing the footage down by changing the speed from 100% to 75 or 50%. I'm using RCA cables to connect my cam to my tv. I DO notice that on my little 14" tv sometimes graphics and titles from tv shows give an audio "scratching" noise when they come on the screen...could it be that my tv is too sharp or something? What do you mean by "the results were pretty much what I expected" when slowing footage down. Thanks for your reply, I look forward to seeing if I can figure this problem out...

June 22nd, 2004, 08:26 PM	#4
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	OK, that's helpful. Personally I find all consumer TV's to be way over-sharpened and turn it down to the minimum. This is especially true of LCD panels, if that's what you mean by "flat screen". I have a Sony 17" widescreen LCD video monitor, and when I first plugged my camera into it was really upset by the image. Reducing the sharpness to the minimum made a huge difference. For one thing, the oversharpening really accentuates any noise in the picture. But if you mean a 14" consumer flat screen CRT TV, all of those that I've owned (including a Sony WEGA) had really poor image quality and I gave up using them with FCP. Connecting a TV with RCA composite video is also noticeably worse than s-video and very possibly contributes to the problem, however I've never seen a little 14" CRT TV with s-video in. You might try exporting your slo-mo sequence back to tape, then take your camera to a store where you can hook it up to a better monitor with an s-video cable and see if the problem goes away. If you're shooting in automatic mode then of course you aren't performing a controlled experiment since you don't know what shutter speed the camera is choosing. Under bright conditions it could be raising that as high as 1/1000 sec. You can look at the data code on your tape by pressing the button under the LCD screen and that will tell you the shutter speed. High shutter speeds can cause an effect like you mention, especially when slowed down. Try using manual mode (silver switch in the center position between auto-lock and hold). Now press the shutter speed button and make sure it reads 60. Press the exposure button and manually adjust the iris properly; if you can't prevent overexposure under bright conditions use the ND filter. Now see if your results look better in FCE. You should also choose the "frame blending" option or you may very well see problems like you describe. "Pretty much what I expected" meant that when you're only capturing 30 full images per second your raw data is limited and you can only slow it down so far. Special cameras are used to shoot high quality slow motion. But you should be able to get a pretty nice 50% speed reduction.