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Jitter Problems
I have this problem with jitter. It only shows up when I animate an object, (i.e. – to move a re-sized video clip across the frame). If the clips are static, the motion back, and title all look fine, but if I move these video clips (animation codecs) there’s a serious jitter associated with the motion. I have tried motion blur, frame blending, gaussian blur and same results. I also tried no frame dominance, which yielded a very poor result. I also tried using other codecs. Please help!!!
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9 Replies
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It sounds like field reversal….Where are you viewing the rendered file ??
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Also, search the COW for “judder”. Do an advanced search.
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NTSC Standard Def at 29.97 lower frames first is what I’m doing. I’m looking at on a Sony PVM-20M4U Production Monitor. I import and render everything as lower fields first. I even tried to do a .tif still frame import (import each still as a full frame) with lower and none. I tried using animation codec and none compressed also.
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If you interpreted your footage correctly (e.g. lower field first for DV) and you rendered correctly for your output device (e.g. LFF or progressive for DV), and you’re viewing it on an interlaced monitor, then you may have the dreaded “judder”.
It’s an optical phenomenon, not a technical one. It happens at certain speeds, when the motion is regular and in a straight line. The eye can actually discern the individual frames in this situation, so persistence of vision breaks down, essentially. You can see it in movies — one example can be seen in “Inside Man”, where a pan across a small room showed horrible judder. It could also be seen in that WWI spot for Stella Artois, as the camera panned around a square in a small town.
You have to accept it, or change the motion so it is not in a straight line, or add distracting elements … anything so the eye does not get so comfortable with the motion that is is able to discern the individual frames. Blur won’t do it, but sometimes (!) rendering to fields does it. Maybe not in your case.
That’s my take on it, anyway.
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I don’t even see a search engine in cow. Can you add any details?
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It’s on the left, third line under the Cow image.
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Does it matter that I am not doing dv, but 720 X 486 / NTSC to BETA SP? Originally, I stayed with lff throughout the entire project. A work around I’ve used was to export the comp as multiple still images with lff and it would improve. For example, I took a very large picture of my web site and applied key frames to make it scroll. This had much judder, but much less after exporting multiple frames in the .tiff format. Sometimes, it also looks better if I use no field dominance. But when & when not is still confusing.
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No, it doesn’t matter. DV was just an example. Most capture cards use LFF, but some use UFF. To see if you have interpreted the interlaced footage correctly, alt-double-click on it in the project window, then step through it with the PageDn key. If the footage moves forward normally, you’ve interpreted correctly. If it goes back and forth, you’ve interpreted incorrectly and should switch the interpretation to UFF or vice-versa.
You can render fields or frames (progressive) if you want — it is an aesthetic choice.
BTW, the term is “render frames”, “render with no fields” or render progressive”, not “use no field dominance”. 🙂 We’re actually talking about field order when we talk about UFF or LFF. Field dominance relates to the field on which an NLE places a transition, not which spatial field plays or records first. Apple (and others) use the wrong term.
Hope that helps.
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I m currently working on an AVCHD file using AE-CS5..The problem i m facing is whenever i render the video to H264 format the footage in which i have pan the camera shows jitters the original video(AVCHD) is without those jitters only when i export it out the jitter is seen..
Can you please help me with this..
Also another thing can you please let me knw what does the bitrate in a video signify..Thanks,
Pushkaraj
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