What exactly is NVIDIA Purevideo?
NVIDIA PureVideo is a dedicated Video Processing (VP) engine within the GeForce 6 Series and newer Graphics Processing Unit (GPU). The NVIDIA GeForce 6 and newer Series of GPUs serve as two chips—graphics processor and video processor—in one.
The NVIDIA PureVideo Decoder is software used with a compatible graphics processor that "decodes/decompresses" video data streams such as MPEG-2 from DVD. The purpose of the MPEG-2 CODEC (COder/DECoder) is to reduce the size of video so high quality video can fit onto a DVD Disc. The codec algorithms may be implemented almost entirely in a GPU such as in the GeForce 6 series and higher, or via software running on the host CPU.
The NVIDIA PureVideo Processor can also decode H.264, VC-1, and WMV. For more information please see the following link.