I know this has been asked once before on this forum but that was 8 years ago and I was wondering if anything has changed.
I've been asked to animate on a number of large LED banners for stadiums. The dimensions consist of 18288 x 56px, 30824 x 72px to name but a few. AE's maximum canvas size is 30000 x 30000px, is there any way around this?
Regarding dimensions that AE can render out, I have been exporting to .MOV and using Wondershare to convert to .AVI but the larger files are glitchy and no way usable.
Can't you export from QT to the avi format? You need the pro version (last one was v7.7 if memory serves.) there's also the free and incredibly fast and robust ffmpeg.
As for size. Double check the size of that screen, AE does one of the larger cavases and the playback boxes at the stadium aren't usually as robust as that. Is it possible they have stiched two screens/players together? Also sometimes the multiplexer needs a format where the footage is in a block of two 72 pixel high rows, one over the other but half the total width and it cherry picks the pixels to distribute. So the footage kind of has a carriage return halfway along.