jittering/flickering motion

Are you zooming or panning photos or clips? If it's photos, I had that exact same problem. What you need to change is the Field Dominance for your sequence. Choose Sequence from the menu bar, then click on Settings. In the first tab, the default one that opens with the window, there is a bar next to Field Dominance. Choose "none". That should solve your problem.

If it's video that might be something different. My guess is you shouldn't be zooming or panning with SD footage anyway. But that's up in the air.

Give the Field Dominance a try and see what happens.

Good luck!


jesse.

I actually asked a similar question to that earlier. (For future reference, try searching the forum before posting something. You might find the answer, and also avoid a biting remark from somebody who's tired of answering the same question for yet another time.)

Here's the link to the post: http://discussions.apple.com/message.jspa?messageID=5527512#5527512

It makes sense, I think. I'm not a guru as far as all the technical aspects go, but for what it's worth.... If it still doesn't make sense put up a question about it.


jesse.

I really don't know. In my project I changed the Field Dominance and left the ratio at 3:2. Then I exported to Quicktime Movie, then burned through DSP. The end product looked fine with no jitter - assuming we're even talking about the same kind of jitter.

So maybe that's your problem, maybe it's not. You've reached the end of my experience....


jk

It's unlikely the compression to DVD is causing the problem. The problem exists already in your footage but, the way you are monitoring does not show it up until you have burned the DVD and FINALLY look at the footage on an NTSC/PAL screen.

The flickering you see is an artifact of the interlaced nature of video. It is a result of either very thin (often horizontal) elements that exist on one scanline as is common in text/ titling or scanned images with a great deal of detail in high contrast. (Note: It does no good to import images hugely larger than the necessary pixel dimensions of the video sequence. All it does is force FCP to work harder at interpolation.)

As the alternate fields play, the offending element is essentially being turned on/off creating the impression of a flicker. The basic strategy is to get the element to exist over two scanlines so it is refreshed every time the field plays and/or to reduce the amount of contrast so the difference between ON and OFF is not noticeable.

Things to try (In increasing order of image degradation)

= (in FCP) field order>none

= (in FCP or Photoshop) reduce whites by 10% - reduces overly bright areas

= (in FCP) flicker filter - minimum

= (in Photoshop) motion blur>vertical> .2 - .5 pixels - blurs vertically only

= (In FCP or Photoshop) Gaussian blur> .2 - .5 pixels -blurs both horizontally as well as vertically

= (in FCP or Photoshop) deinterlace - throws away half the image and is generally not appropriate on scanned or still images.

One neat trick is to use the selection tool to limit area you apply the vertical and/or gaussian blur to only the troublesome part rather than indiscriminately soften the entire thing.

Remember: Unless you are viewing your work in the appropriate external NTSC/PAL monitor, you are playing blind. The computer monitor only shows you a proxy image.

good luck.
x

A frame of video (NTSC and PAL) are made up of two fields. The upper field consists of lines 1,3, 5,7 etc. The lower field consists of lines 2,4,6,8 etc.. DV is lower field dominant, which means, the lower field is the first to be recorded/played back. Each field represents 720x240 pixels of information. When combined, they create the 720x480 frame (using DV-NTSC as an example).

In NTSC video, the fields are refreshed every 1/60 of second making one FRAME = 1/30 sec. A still image (1 FRAME) captured or frozen from video will contain two fields. If there is much movement in the scene, the difference between the first and second fields can be noticeable. This difference is sometimes described as combing (the edges of vertical elements look like the teeth of a comb). This is because of the time difference between when the fields were recorded (1/60 sec) the element is in a different position in each field.

In order to get a clear image from a video still that exhibits combing, you need to deinterlace, that is, throw away one field. Since a field represents 1/2 of the image information (720x240 for DV-NTSC), whatever program you use must re-create the missing info in order to maintain the pixel count of the video (720x480 for DV-NTSC). Some programs do a better job than others. In any case, you will end up with a softened image as the newly generated pixels are usually an AVERAGE of the difference between the lines. Much sharpness is lost.

Still images from scans or digital photographs DO NOT have fields. Nothing is gained by deinterlacing them since they *were never interlaced*.

You really need to read the manuals and find some books that explain the basics of the technology you are using. Understanding this material will make you a more effective editor.

x

Studio's a master at this stuff. Got it all written on the back of his hand though.

Anyway - I do have one question...

What was the original footage you shot? What format, frame rate and what camera?

That would tell ME a lot about what the problem might be.

Thanks,

CaptM

I could tell you what you shouldn't do with that footage if it isn't de-interlaced. Don't do any corner pining, masking, scaling, etc. Don't even stretch it by a pixel in the timeline because it will come out funky looking (in a bad way).
I see this a lot. People try to mixmatch formats from D1 to DV. By stretching out the footage vertically to match either size.
If you think the problem is coming from your footage. de-interlace it, import it back in FCP and see if it plays nicely this time around.
It would also help describing the acquisition footage's properties, and your timeline's sequence settings. I don't think I've seen you give precise details thus far.
I'm willing to bet there's a video format mixmatch there somewhere.

Ok. Which settings are you using in your transcoding app? (list EVERY setting), Which transcoding app are you using?
Is the flicker occurring on thin lines only (field flicker) or the entire image?
If the first is your answer, then heed the advice of the users above, and add a soft blur (by 0.x pixel increments) to your image.

This post is for Jesse. Just wanted to say thank you for answering a question that has been killing me for nearly a year regarding flickering text and images. Changing the field dominance to none worked! I tried everything else I could think of and posted several times to various boards with no answer. This flicker problem only started happening after I upgraded to FCP 5. Perhaps the default in FCP 4 was field dominance none? Either way, problem solved....Just thought I'd say thanks.