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Unwanted scrolling line
Does anyone know if an unwanted line that scrolls upward across a video clip is the result of a capture problem, a limitation of the Sony HDRFX1 camera I used, or a damaged mini dv tape?
FYI, I can’t see the line when I play the scene on the camera’s LCD or when I project it with a PT-AE2000U from my Mac Pro. But I see it when working in FCP, QT, and Shake on my Apple Cinema Display Screen.
The problem closeup scene was shot on auto focus against a green screen, and the ballerina, who is wearing red, moves right up to and away from the camera repeatedly. The line doesn’t appear anywhere else on the mini dv tape. The line looks like a soft rolling wave, and on occasion but less frequently, like a pixelated sideways break.
So far I’ve tried to recapture the scene using multiple FCP capture settings; have trashed my preferences in case those got corrupted; and recently had my ATI Radeon X1900 PCI card replaced with a revised 2 version.
I appreciate any ideas or fixes.
Charlotte Warner
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7 Replies
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Can you post a frame of it?
Richard M. Harrington, PMP
Author: Photoshop for Video, Understanding Adobe Photoshop, and ATS:iWork
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If you don’t see it on the tape and it doesn’t show up when projecting the timeline on a video projector it sounds like a ground loop type of issue that is only effecting your cinema display. Red and green are quite opposite and are represented by different electronic values and perhaps this type scene is susceptible to weak sync or subcarrier signals in your existing power supply or wiring system.
Try writing that section to tape and see if it plays ok. It could be just effecting your cinema display.
You could also try legalizing your colors or tweeking their levels in color to see if that helps.
“everything is broken” ……Bob Dylan
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I don’t have the means of posting the clip, Richard. Thanks for offering.
Charlotte Warner
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Thank you, Rennie. I suspect the same, which is why I bothered to mention the red/green color + auto-focus shift challenges, in case. I have a feeling that I’m running up against the limits of HDV technology with this scene.
I will take your suggestion and write that clip to tape, and then screen the tape on another device (other than my Apple Cinema Display). It will be a couple of days before I have access to other playback devices. But I will post my results.
If anyone has any other theories, tests, or angles, fire away, please.
Thanks, Rennie and readers.
Charlotte Warner
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Well, sometimes the solution is so simple.
After spending the entire weekend trying to troubleshoot this problem down, I figured it out, many, many thanks to Rennie’s list of possible causes.
The unwanted scrolling line was indeed a ground loop problem, a stray interference signal.
The rippling line disappeared after I moved my Cinema Display screen’s DVI to ADC adapter apart from the other cables, surge protector, etc.
Thank you SO much, Rennie, and Creative Cow for your help! Now I can return to what I’m better at–the creative work 🙂
Charlotte Warner
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Thank you for the follow up and kind words Charlotte, I’m glad I was able to offer some useful suggestions.
I fear we are lured into this profession by artistic expression but eventually we all get converted into techie geeks 🙂
“everything is broken” ……Bob Dylan
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Oh yeah, you are sooo right about that.
Charlotte Warner
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