stuttering playback
by apxq12
on
May 21, 2007 at 2:50:58 pm
I'm doing a project for my job in which I have created some video transitions in photoshop and brought them together with 5 pre-existing quick time video clips in After Effects 7.0.
The QT clips play fine on their own (before After Effects), and even playback fine within the program with a RAM preview, but after I render everything out, the QT clips (now all together in 1 project with the transitions), stutter or jerk when I play the project back.
It may be important to note that:
This stuttering only happens on 2 of the 5 clips;
There's been no editing done to the original QT clips at all, they
are just dropped into AE and used "as is"; and
Although the file is large, (145kb), this PC is new and space is
not an issue.
Does anyone have any ideas on how to fix this? If so, please explain things on a beginner level as I am still new with After Effects. Any help at all would be GREATLY appreciated.
Thanks,
Angie
Re: stuttering playback by moldyboot on May 21, 2007 at 3:03:50 pm
what codec did you render too?
my guess is the data rate of the movie files are too great for your disk to playback in realtime. your original files will play back fine, if the data rate of those files fits your drive specs... dv, many mpg settings, etc. are low data rates; uncompressed or losseless codecs are higher data rates, and may be causing problems with a normal drive.
ram previews will play in realtime because they get rendered to ram, rather than disk, and thus more capable of high data rates.
Re: stuttering playback by beenyweenies on May 21, 2007 at 6:20:06 pm
You will need to tell us more about the various settings, such as the codec used in the source Quicktimes, as well as the codec and settings used for the Quicktimes you output from After Effects. Beyond that, you should do a simple test. Pull the rendered Quicktimes BACK into After Effects and do a RAM preview on them:
1. If the files play smoothly, chances are good that the files are too large to play back smoothly in Quicktime Player, which is normal. Uncompressed video has a very high data rate that is greater than the speed of most hard disks, processor capabilities etc.
2. If the file is still stuttering in RAM preview, you may have rendered it out to a different frame rate than the source material. To check, open one of your source files in Quicktime Player and choose Window>Show Movie Info. This will tell you the codec, size and frame rate of the source clip. Open the rendered clip and do the same thing, verifying that the settings match.
Re: stuttering playback by apxq12 on May 22, 2007 at 1:00:56 pm
Okay...like I said, I'm kinda new to this game, so bare with me if I give a stupid answer to one of your questions.
The infor on the source QT is:
Sorenson Video 3
720x480
Millions
fps: 29.97
Data Size: 14.95MB
Data Rate: 793.80KB
When I output the quicktime movie from AE:
Sorenson Video 3
1280x768
Millions
fps: 29.20
Data Size: 96.18MB
Data Rate: 837.12KB
I brought a the file I rendered (that stutters on play back) into AE and tried a RAM preview - stuttering is still there even in RAM preview. The only thing I changed is the size, but I've just noticed that the fps rate has changed. What's up with that, and more importantly, how's it fixed? Do you think that's the problem since everything else seems to playback fine except for 2 of the 5 source clips?
Re: stuttering playback by moldyboot on May 22, 2007 at 1:51:42 pm
it would seem that the issue is probably the frame rate. select one of your comps in the project window. then, from the compostion menu, choose composition settings and set the frame rate to the same frame rate as the original footage.
if you are rendering with render settings other than 'best settings' (default), then make sure in the render settings that the frame rate is set to the same as the comp (and footage)settings. you might even make sure that the output module for sorenson 3 is also set to the same frame rate (although i believe that setting may be over ridden by render settings).
Re: stuttering playback by apxq12 on May 22, 2007 at 2:48:01 pm
Thanks a MILLION! I don't know why, but even though I had set the frame rate in the comp settings correctly, it was wrong in the render settings. I just did a small render of the problem section and things seem to be okay now.
