In the earyly part of this article, we mentioned that NVIDIA has updated the PureVideo HD video engine integrated into the GeForce 8600 / 8500 GPUs and have incorporated a few new features specifically designed to enhance playback of cutting edge HD content. The name of the engine remains PureVideo HD, however, the GeForce 8600 is capable of even more than the GeForce 8800 in regard to HD video playback.
This high-level overview shows that the GeForce 8600 and GeForce 8500 GPUs are equipped with a second generation PureVideo HD video processor and a new BSP engine. BSP in this instance stands for "Bitstream Processor". Not pictured in this diagram is another new addition dubbed the AES128 engine. As its name imples, the AES128 engine handles on-board hardware decryption of HD movie content.
The combination of the the second generation PureVideo HD and BSP / AES128 engines means the new architecture can handle 100% of the CABAC and H.264 video decoding necessary to provide full specifcation playback of Blu-Ray and HD DVD content, without straining the resources of the host CPU.
The second gen PureVideo HD engine handles CPU offloading of IDCT, and motion compensation and deblocking fucntions of for MPEG-2, VC-1, and H.262 playback. The BSP Engine handles H.264 CABAC (Context Adaptive Binary Arithmetic Coding) and CAVLC (Context Adaptive Variable Length Coding) reverse entropy decoding, and the AES128 engine takes care of decryption.