I have a bad banding issue that seems to have only popped up since using Lion - not sure if 64 bit has anything to do with this or not.
What I do know is this: My old machine - which is running Snow Leopard and which I did not boot in 64-bit - never gave me any banding problems in After Effects CS5. I would typically have a 1080p project in which I would throw a solid of the same resolution over with an ellipse mask feathered to around 600 to create a vignette - never saw any banding.
Now, on my work machine which runs Lion, I'm still using AE CS5 - with all of the same settings - and the same solid feathered the same amount produces a very faint but clear border where the feathering "ends" and the middle part of the masked solid creating the vignette goes from semi-transparent to 100% transparent. Hopefully this makes some sort of sense.
Here is the info on the machine in which I am having problems in case that is relevant:
2 x 3.2 Ghz Quad-Core Intel Xeon
NVIDIA GeForce 8800 GT 512 MB
OS X Lion 10.7.2
After Effects CS5
Can anyone help me understand this? Thanks again for any advice - I really appreciate it!
i doubt that the os has anything to do with banding, though there are some issues with cs5 and lion... the graphics card might, so i would make sure that ae is not using opengl for previews (preferences>previews). also differences between the monitors may also have something to do with it.
what you might try doing is rendering a frame at work that shows banding but that you think wouldn't show banding at home. then take that still home, throw it into ae and see if you see banding.