The "repeat-frame" effect seen in imported MPEGs
by david lincoln brooks
on
Apr 13, 2008 at 4:47:33 pm
I've been trying to import MPEG2 based footage into PREMIERE and AECS3.
I've already read that this can be tricky to do.
I'm literally importing a VOB into these softwares, but changing the file extension first to AVI. Changing the file extension does indeed permit AE and Pr to accept the video file.
But I'm getting a curious, undesirable effect: the motion in the video is jerky, or rather it appears as though every three frames or so, those selfsame frames are beimng repeated. So little bodily actions in human figures, let's say, get played twice, both in the sogftware preview wndows, and if those videos are exported (with any codec) in AE or Pr.
Can you shed a little technicfal light into what's going on here? hat causes that "repetition of frames" jerky effect? More importantly, how can it be eliminated, when an MPEG2 (VOB) is your input footage?
Thanks in advance, DAVE
Hello all. I'm a 3D artists and digital musician in Central Texas. I hope to get to know you all here!
Re: The "repeat-frame" effect seen in imported MPEGs by Lars Bunch on Apr 14, 2008 at 1:55:01 am
Hi,
When you say you are using VOB files, are you taking them directly off a playable DVD? If so, you might be able to find shareware that can extract the video and create a Quicktime file. "Handbrake" under OS-X is a good one. I'm not sure if there is anything under windows, but my guess is there is some shareware out there that would work for you.
If you can open the VOB/AVI file in quicktime or Windows Media Encoder, you might be able to export a file sequence and then import that into AE. Quicktime Pro can export a file sequence and it make be better able to read an Mpeg2 than AE.
The nature of Mpeg2 files makes them really difficult to work with in a program that expects to see whole discrete frames. Whole frames are only stored approximately every 12 frames and the frames in between are calculated from motion delta data. So what may be happening is that AE looks at a section of video, sees a whole frame and loads that up, but when it sees the next frame it can't make sense of it so it uses the nearest full frame it can find. (I don't know much about what is actually happening here so take my explanation with a bit of salt.)
Anyway, the best approach is to turn the VOB/AVI file into something else before inflicting it on poor, defenseless after effects.
