Which capture card / mixer can do this ?

[KMedia]

I want to do the following application:
A CCTV camera (PAL)will be attached to a video capture card which will show live full screen view (from the camera) on the computer monitor but I want my application to run over the camera view. My application is also full screen and draws only rectangles and circles but it has a lot of black area in it. So when the application is overlayed on camera input, black regions should show the live video and the pixels that have the circle and rectangles should not show the live video and instead show the rectangles and the circles.

I also want still frame capture (only black & white capture will do) and want to use the captured data to calculate the distance of an object from a rectangle drawn by my application at the time of capture. Please let me know this capture will give me output in which format.
I have found that Aver EZCapture card is still used in such an application developed by somebody. But I do not know how overlay is done and which file is generated on still frame capture.
Please reply,
Thanks All.
KMEDIA.

[KMedia]

I want to do the following application:
A CCTV camera (PAL)will be attached to a video capture card which will show live full screen view (from the camera) on the computer monitor but I want my application to run over the camera view. My application is also full screen and draws only rectangles and circles but it has a lot of black area in it. So when the application is overlayed on camera input, black regions should show the live video and the pixels that have the circle and rectangles should not show the live video and instead show the rectangles and the circles.

I also want still frame capture (only black & white capture will do) and want to use the captured data to calculate the distance of an object from a rectangle drawn by my application at the time of capture. Please let me know this capture will give me output in which format.
I have found that Aver EZCapture card is still used in such an application developed by somebody. But I do not know how overlay is done and which file is generated on still frame capture.
Please reply,
Thanks All.
KMEDIA.