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Rotoscoping

Posted: Fri, 11th Apr 2008, 5:52am

Post 1 of 6

austinfd

Force: 400 | Joined: 25th Mar 2008 | Posts: 6

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Gold Member

I'm trying to add a few light swords to a clip.

In each frame, I draw or reposition my neon-light and then click the tight arrow. typically, moving one frame doesn't change anything, not that the object hasn't moved, but that the image stays the same. If I move two frames ahead, I find I can reposition my neon shape. However, when I review the scene, every other frame is off... usually by the distance between the prior and next frames. Then I have to go back through the whole scene and adjust those frames again....

I've solved it by doing this:

If I edit on frame A, and then click RIGHT, frame B usually has no change, so I go ahead to frame C. Then, LEFT to frame B and then I can go ahead to frame D.... repeat.

It seems silly to haev to back track like that. Is it just that my computer isn't processing the next frames as fast as I expect? Or is there something I am missing. So for changing my canvas preferences doesn't seem to fix the issue.

Thanks!
Posted: Fri, 11th Apr 2008, 6:57am

Post 2 of 6

FXhomer46784

Force: 493 | Joined: 24th Dec 2007 | Posts: 329

EffectsLab Pro User Windows User

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FXhomer75407 wrote:

In each frame, I draw or reposition my neon-light and then click the tight arrow. typically, moving one frame doesn't change anything, not that the object hasn't moved, but that the image stays the same. If I move two frames ahead, I find I can reposition my neon shape. However, when I review the scene, every other frame is off... usually by the distance between the prior and next frames. Then I have to go back through the whole scene and adjust those frames again....
That would be because you're keyframing, which means the computer fills in the gap between un-keyframed frames. If I correctly understand what you're saying, a better solution would be:
1. edit frame A
2. add a new keyframe on frame B (but don't move it)
3. edit frame C
4. add a new keyframe on frame D (etc.)

Someone else is probably more of an expert here than me, but if every two frames (or probably fields in actuality) is the same, might this be an interlacing/progressive thing (meaning the project is set to interlace when it is referencing progressive footage)? If so, I thing the whole issue would be resolved once and for all by changing this setting.
Posted: Fri, 11th Apr 2008, 9:09am

Post 3 of 6

Simon K Jones

Force: 27955 | Joined: 1st Jan 2002 | Posts: 11683

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FXhome Team Member

I think the greater issue here isn't the actual rotoscoping, but why your video has duplicated frames.

What kind of footage are you using?
Posted: Sun, 13th Apr 2008, 10:58am

Post 4 of 6

austinfd

Force: 400 | Joined: 25th Mar 2008 | Posts: 6

EffectsLab Pro User

Gold Member

FXhomer46784 wrote:


If I correctly understand what you're saying, a better solution would be:
1. edit frame A
2. add a new keyframe on frame B (but don't move it)
3. edit frame C
4. add a new keyframe on frame D (etc.)

Someone else is probably more of an expert here than me, but if every two frames (or probably fields in actuality) is the same, might this be an interlacing/progressive thing (meaning the project is set to interlace when it is referencing progressive footage)? If so, I thing the whole issue would be resolved once and for all by changing this setting.
I'm not sure how that is different from what I'm already doing. I thought by editing the effect, a new keyframe is added. My issue is that I don't get to see frame B until I've edited frame C and go back to frame B

---


I think the greater issue here isn't the actual rotoscoping, but why your video has duplicated frames.

What kind of footage are you using?
I think that was a poor way to describe my problem. There aren't any duplicate frames. I was just attempting to describe what I saw: When I add the sword on frame A, and then press -> the image doesn't change on frame B... until I go to frame C, position the sword, and then <- back to frame B. When I go back, to frame B, the sword is usually off, and I need to reposition it there.

But if it does indeed matter, I am using mini DV footage shot in 16:9 It's an iMovie-exported .mov file
Posted: Sun, 13th Apr 2008, 3:16pm

Post 5 of 6

Axeman

Force: 17995 | Joined: 20th Jan 2002 | Posts: 6124

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SuperUser

It think its just a matter of understanding keyframing and tweening. When you set a lightsaber in position on frame 1 at point "A", and then move to frame 3 and set it at point "B", EffectsLab will automatically do its best to interpolate the frames in between. In this case, this means that frame 2 will be set to exactly halfway between keyframe 1 and keyframe 3. For straightforward animation this is a necessity, but with rotoscoping, it won't always line up with the blade you are tracking, as you have discovered.
Posted: Sun, 13th Apr 2008, 5:46pm

Post 6 of 6

FXhomer46784

Force: 493 | Joined: 24th Dec 2007 | Posts: 329

EffectsLab Pro User Windows User

Gold Member

If we're understanding you correctly:

Axeman wrote:

It think its just a matter of understanding keyframing and tweening. When you set a lightsaber in position on frame 1 at point "A", and then move to frame 3 and set it at point "B", EffectsLab will automatically do its best to interpolate the frames in between. In this case, this means that frame 2 will be set to exactly halfway between keyframe 1 and keyframe 3. For straightforward animation this is a necessity, but with rotoscoping, it won't always line up with the blade you are tracking, as you have discovered.
Which is why I said to add keyframe B before keyframe C. B only changes with C because you don't have a keyframe on B. If A and B are identical frames they both need identical keyframes before you do anything to C. Sorry if this is confusing, but there's no good way to describe it.

But like Axeman said, you really should just get rid of the duplicate frames, which must have something to do with your project settings. Having duplicated frames will do nothing except give you twice as much work (and possibly half the frame rate in the finished project sad).