Hi John or anyone else who knows...
I am making movie brushes, on my PC version of Studio Artist 4, and it seems like the biggest size I can make a movie to use as a movie brush is 300 x 300 px. If I make a movie bigger, and/or not square, it does not work, nothing is painted onto the canvas when I paint with the brush, although movies at 300x300 work just fine. Is 300x300 px really the biggest size for movie brushes or am I doing something wrong?
OK I have figured something out, maybe it is a bug? On my mac version of SA 3.5 I can use a 640x480 movie as a movie brush, but the same movie does not work as a movie brush on my Windows PC SA4. Any ideas? I would try it on my other mac laptop that has SA4 on it, but that one is having major problems and freezes up on startup, so I can't try it right now. The mac I am using with SA 3.5 is my older laptop.
I've definitely used movie brushes with larger frame sizes than 300x300 pixels on a regular basis.
Here's a test i just ran using a 1024x1024 movie brush.
And i've used larger frame sizes when working with source movies for stack filtering with temporal ip op effects. And the aspect ratio shouldn't make any difference. Unless you are using some codec that has restricted frame sizes (avid comes to mind in that regard).
In V4, if the movie frame size if larger than a set default, Studio Artist automatically switches the MB Load Status from preload to disk draw. Preload loads the entire movie into ram memory, which will chew up ridiculous amount of memory for large frame sizes or a large number of frames in the movie. I'm not sure if 3.5 is smart about doing that. So you might want to set it to disk draw before loading a new movie brush if you are working with memory intensive movies. Preload decompresses each frame, so the memory footprint of a preloaded movie brush is going to be way larger than what you see for a compressed movie file.
Also, the entire brush cache is memory allocated (as defined in Brush Modulation control panel based on the base frame size for the movie). So you might want to check what you have that set to. Remember, the number of brush cache memory allocations is the # of sizes times the # of orientations. And i've seen people do things like set the max brush size to some large number greater than 100% for weird reasons. So that's a way to chew up ridiculous amounts of memory for the brush cache allocation if you do are careless about you have the Brush Modulation control panel setup.
I am of course using a mac for my testing right now. I'll hunt down a windows machine later today and try some tests there, but i'm unclear on why that would make any difference.