PureVideo 1
Also known as simply PureVideo. First introduced with the GeForce 6 series, the original PureVideo engine improved upon the GeForce/FX's video-engine (VPE) by adding better deinterlacing algorithms and finer video-resizing for overlays. Compatibility with DirectX 9's VMR9 renderer was also improved. PureVideo inherited the MPEG-2 decoding pipeline from its predecessor, VPE. But in later models of the GeForce 6, PureVideo also offered hardware acceleration for VC-1 and H.264 video, though the degree of acceleration is limited when benchmarked side by side with MPEG-2 video. PureVideo offloads the entire MPEG-2 pipeline excluding run length decoding, variable length decoding, and inverse quantization.[1]
[edit] PureVideo 2
While many PureVideo-capable cards could in fact play downloadable 1080p-video with a sufficiently fast host PC, HD DVD and Blu-ray's specifications push many such systems beyond their limits. In particular, one of the two compression-codes in H.264/AVC high-profile, CABAC, is notoriously unfriendly towards general-purpose CPUs. PureVideo 2 adds a bitstream processor (BSP) and enhanced video processor (VP2) to completely offload AACS-decryption and H.264-decoding. For VC-1 decoding, PureVideo 2 offloads the inverse discrete cosine transform (iDCT) and motion compensation stages, and relies on the host CPU to handle the bitstream processing/entropy stage of the video pipeline.[2]