time distortion

[Mylenium]

hello out there!

i am using adobe after-effects cs3 and i want to do a time distortion: i have a movie and i want the upper half of the screen display the future of the clip und the half at the buttom see the past of the clip. (maybe 4 seconds difference).
i used the effect: time-dispacement and as source for the displace i´ve created a layer with a fade from white to black. this works very well but the result has a very low resolution. when i see faster movements i can see the "time-stripes". i tried to blow the effects up to 128 fps resolution, but i still see the time blocks. i want to look it smoother!

has anyone an idea?

greez
stegge

Switch your project to 16bpc. The quantization happens in the source displacement map. Won't solve all issues, but should minimize them.

Mylenium

[stegge]

that turnes the picture a little bit smoother, but it is still not a good result. is there maybe another way to handle it, or a better plugin to solve the problem?

[Khalor]

I'm not an After Effects guru like Mylenium here, and haven't used the time displacement plugin much, so I could be way off the mark, but I just did a bit of math and I think the problem you're facing is this:


I'll assume you're using SD DV PAL footage, therefore 25fps at 720x576.

A delay of 4 seconds between the top and bottom of the footage
4 seconds x 25 frames = 100 frames
Gives you essentially 100 layers to stagger vertically along your composition
However, PAL is 576 lines vertical. So you're spacing 100 layers over 576 lines, so:
576 lines / 100 time-independent layers = a change in time every 5.76 lines vertically up your composition.
The result? Jaggies - visible banding where the time changes layer approximately every 6th line.
You would need footage at 144 fps (576 lines / 4 seconds) to get a truely accurate one-for-one mapping of different states in time to each line.

That said, there are plugins out there for faking the extra frames per second (hereafter referred to as temporal resolution) - RE:vision Effects (http://www.revisionfx.com/) does a few good ones like Twixtor. Never tried to use them in a situation like this before though.

I hope that helps.

[dangraham]

Not sure if this is what you're looking for, but have you made sure that the frame blending mode is checked to smooth next to your layer?

[stegge]

all these tipps have made the result a litlle bit better. it is still not perfect, i think, i have to mix the different procedures.

thanx a a lot

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.