Video Jerk, but it was ok before damnit !

#1

Hi i have a project in AE CS4, it’s for a portfolio.
Problem is : When i render the video and i look it, i see many random jerk in the playback (Like it go forward then backward right after the next frame).

So i came back in AE to take a look and indeed i see the jerk when i do a ram preview.
Hmmm ok, i open the orignal source video to see if the jerk was there but no ! Everything is smooth and clean its only when i import the video in After effect the jerk appear.

1 week before i did see 1 jerk in a video… i say, aa what ever i will take care later, then i copy files into another external hard drive and get back home, since i see plenty of the same jerk in random video.

Other info : WMV, original video in 29,97 (composition in 30) i use time remap (even without it i see it but less… the time remap seem to accentuate the problem.

Here a small preview of the bug :
http://www.youtube.com/watch?v=tZ6mj3bakms

#2

So why time remap? If the original footage is 29.9, why not render at 29.9?

#3

Because i needed to accelerate some part.
What ever the frame rate i choose(in composition and output) i always have the jerk

#4

I don’t think this is a time remap issue, as after effects conforms video for output as long as it’s properly interpreted (which you would see in the layer window). I too have seen this jerky pmotion and other strange playback issues upon export. Unfortunately, I have yet to discover the culprit.

#5

The only way i find to fix that is to make png sequence of my video.

#6

This is caused by the frame interpolation from Time Remapping or Time scaling. Something like this is tough to overcome because AfterEffects will not interpret frames correctly. I believe that there are plug-ins out there that do what you want… But I have no idea on if they work well.

Sometimes (only sometimes) if your footage is pre-comped, pre-rendering it helps.

#7

Well the problem is after effect (nothing else) the video are fine in adobe premiere.
(Even without time remap)

The only way i found to resolve my problem is to make images sequence (png). Heavy… but faster render and no more problem of frame.

#8

I get that exact problem with videos from my camcorder. I have to convert them in Premiere where they don’t jump about, then export to After Effects as an image sequence or similar. If you’re using png, the compression helps with filesize.

#9

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