Capturing Video to VRAM using AVStream
Beginning in Windows Vista, AVStream drivers can capture video and audio directly to the graphics adapter's VRAM. AVStream drivers that existed prior to Windows Vista must first place data in VRAM, transfer it to system memory, and then finally back to VRAM for display.
The new VRAM capture support takes advantage of the GPU scheduling and VRAM virtualization offered by the Windows Vista Display Driver Model.
To capture to VRAM, a device must include capture and display functionality on the same video card.
The following sections describe how to add VRAM capture support to a new or existing driver:
You can find sample code showing VRAM capture in the MSDN Code Gallery's AVStream Simulated Hardware Sample Driver (AVSHwS).