Exports Freeze/Jittery
by Tyler Leisher
on
Jul 24, 2008 at 3:27:17 am
I recently shot a film in 1440x1080 24p, and it runs great when viewed on my computer but when I run it through after effects or premiere and export it as a .mov it is really jittery/jumpy or it just pauses on a frame, then a few seconds later instantly jumps to another frame and freezes on that.
if I render it out as a .wmv or anything else it runs fine, it's just .movs that I have problems with.
I've tried multiple ways of rendering, but my most common one is rendering with photo jpeg (or h264) in best video quality, 1280x720, 24 frames per second and deinterlacing.
Nothing seems to work.
Also, whenever I import the clips it imports them at what looks like a 4:3 resolution, when the file says it is a 1440x1080 file. Any ideas why it is doing that?
Re: Exports Freeze/Jittery by Chris Wright on Jul 24, 2008 at 6:40:05 am
h.264 can get jerky. All the data is there, just quicktime player is really badly programmed. If you play it with Nero player, it will play fine.
Or your file is so huge, it's possible your hard drive can't keep up with the data rate transfer.
Only do this if you don't need lossless or not need to re-import again to recompress.
See what your hard drive can take and limit the codec to that speed.
try jpegmotion 2000 and data rate restrict to kbits/sec:
read the AE help and search box "interpret" for 4:3 and 16:9 workflow
Re: Exports Freeze/Jittery by Dave LaRonde on Jul 24, 2008 at 3:27:57 pm
[Chris Wright]"...h.264 can get jerky. All the data is there, just quicktime player is really badly programmed. "
WILLYOUQUITDEALINGINMISINFORMATION?
It just so happens that After Effects is the culprit. AE can not handle temporally-compressed footage like h.264. Yes, the Adobe literature says it supports h.264. It doesn't.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: Exports Freeze/Jittery by Dave LaRonde on Jul 24, 2008 at 2:50:13 pm
[Tyler Leisher]"I recently shot a film in 1440x1080 24p.... it is really jittery/jumpy or it just pauses on a frame, then a few seconds later instantly jumps to another frame and freezes on that...
...whenever I import the clips it imports them at what looks like a 4:3 resolution, when the file says it is a 1440x1080 file. Any ideas why it is doing that?"
Woo Hoo! Congratulations! You're probably about the 10,000th aspiring filmmaker who has blundered through the HDV workflow intuitively, not looking before you leap, hoping that everything will turn out just fine, and then gets bitten near the end. Sadly, you have a lot of company.
First, that 1440x1080 business: HDV cheaps out by not giving you an entire 1920x1080 image. What did you expect from HDV, miracles or something? It makes the pixels fatter to fill up a 16x9 image. I VERY STRONGLY suggest searching for the topic of "Pixel Aspect Ratio" in AE Help. You will find a wealth of information, and we won't have to yet again write it down here.
Second: since you say you shot 24p in HDV, DID YOU REMEMBER TO REMOVE THE 3:2 PULLDOWN? If you have to ask, "what's pulldown", go back to shooting on a pea-shooter DV Handicam until you do.
Third, your renders look crappy for a couple of reasons: the pulldown issue is one, but the other is NOT your oversight -- it's an erroneous piece of Adobe propaganda, and it results in a VERY common problem for AE users. Read on...
Dave's Stock Answer #1:
If the footage you imported into AE is any kind of the following -- Native HDV, MPEG1, MPEG2, mp4, m2t, H.261 or H.264 -- you need to convert it to a different codec.
These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.
In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
