Re: Pure video = VDPAU ?
Geforce6 and 7 only decodes in hardware Mpeg1/2. The mpeg-4/vc1 is decoded fully in software. Purevideo on these cards mean only postprocessing (sharpening, blurring, scaling, color space conversion, denoising, deinterlacing) done using shaders.
Nvidia on Linux only supports these things which are really supported via hardware because smart people use Linux (such software purevideo would be discovered immediately by users and laughed at). Windows users are IT dumb and will buy/believe in everything what marketing print on box. That is why VDPAU appeared when Geforces started to fully hardware decode mpeg-4/vc1. Before XvMC was enough because GeforceFX/6/7 only have mpeg1/2 iDCT, MC and CSC levels of decoding which in 100% are covered by XvMC and Xv.
Nvidia like other companies know that majority of Linux community are IT geeks so they do not put on us marketing charm because this simply will not work. They know we don't look on colorful boxes but on chipsets and hardware specs. That is why Linux driver is about 15MB rather than 100MB and have almost everything what Windows driver has but without bloatware and other disk wasting crap omnipresent on Windows.