Originally Posted by Deanjo
Only the 32-bit version features VDPAU support. Found here: http://labs.adobe.com/technologies/flashplayer10/
It works fine on 64-bit browsers when you install nspluginwrapper. I've tested it out youtubes 1080p streams on 8200 IGP, 8800GT, GTX-275, and GTX-580 and all are working fine with the 260.19.26 drivers. Perfect vsync and next to nothing for cpu usage (<1%).
Posts at Phoronix's forums also say that the 64-bit version has no video acceleration support: