I hope someone can help me.
I have created a fairly simple video using a few layered compostions. I used cc repeTile to get binary text to strech into lines that switch on and off using a wiggly selector in an offset character animation. I then made rectangular masks over top so that the lines can only be seen within the rectangles. Everything looks great in my RAM preview and in my workspace however once I have rendered using either quicktime, H.264, or lossless, (I've tried with and without Alpha channels) all I get is basically a black screen.
Am I missing a video codec for the repetile effect maybe? Or is it a problem with my masks?
Check and make sure you are looking at the at the active camera. If that doesn't fix it, show us a screenshot.
As Rick said, you will have to be more specific. We don't even know what version of AE you use much less anything about your system, your comp, your layers. Pretty pointless.