Shouldn't be a problem based on the very limited amount of information you've provided. I can only assume that you're computer hates you.
Seriously though, I've had dozens of videos onscreen at the same time in a very old version of AE with no problems, so we are lacking the necessary info to provide you with any help at all.
You haven't told us anything about what version of AE you have 9.0.2? 11.0.1? 12.0.0?
You haven't told us about the format and codec of the footage.
You haven't told us anything about your computer's specs.
If you want useful help, you'll need to give us the information mentioned here.
Love that "your computer hates you" bit, Szalam...
I'll add this, even though it should be obvious: is your video all of sufficient duration to do what you want to do? Do you have these layers of video arranged in the comp so they're all visible at the same time?
Sorry for the lack of details.
I am using AE CS4 22.214.171.124 on a Mac OSX with 4GB memory and 2.4 processor.
Quicktime is 10.0.
I have four 50MB .mp4 videos playing in a grid that are not cropped and are on the top visible layers of my composition. I have tried exporting and rendering the composition as a .mov file and a .mp4 movie at a large and small pixel dimensions (1280x720).
The whole composition plays great until you get to the grid of four 30 seconds videos mentioned above. They flicker on and off for a couple seconds and then disapear in the video. Any thoughts?
Thank you for any feedback you all might have.
I don't have any idea what your composition looks like. If the comp will ram preview correctly then there's either something wrong with the original footage, the interpretation, or there's bug in the codec. You've just not given anyone enough details about your project to have a clue what may be wrong.
After Effects CS4 was terrible at working with .mp4 files (which were new at the time of After Effects CS4 being developed).
Convert those files to something else before trying to work with them in After Effects CS4.
Later versions of After Effects work wirh .mp4 files just fine.
Thank you Todd.
My video worked fine once I converted the .mp4 files to .mov files.