It needs to be PCI and have 256mb memory. When I look at video card specs I don't see anything about Overlay so I am not sure if it has it or not. Thanks!
EDIT: This is to be used on a computer for a video security system that is using 16 cameras.
Pretty much anything is going to support hardware overlay. You don't need 256MB video memory for a "security system" PC either. Even the PCI version of an original Radeon 32MB with SDR VRAM would work fine for what you intend. That said, something like a Geforce 8400 series card or even one of the older Radeon X1xxx series (even an X1300) would be fine. Shouldn't be more than around $30-40.
Well, the installer says it needs 256mb because of the amount of cameras. We can only run 4 cameras with 32mb, 8 with 64mb, 12 with 128mb and 16 with 256mb. He showed us a demonstration with his laptop. He was only able to get 12 cameras working on it because he only had 128mb for his video card.