X-bit labs

Nvidia GeForce 9600 GT: Worthy Rival to ATI Radeon HD 3000 (page 3)

Category: Video

by Alexey Stepin , Yaroslav Lyssenko

[ 03/07/2008 | 10:33 AM ]

PureVideo HD

Contrary to a widespread opinion, the PureVideo HD has not changed on the hardware level. It is architecturally identical to the unit that was introduced in the Nvidia G84 core and then incorporated into the G92. Nvidia’s video-processor provides full hardware support for decoding H.264 and partial hardware support for decoding VC-1. For the latter format, entropic decoding is performed on the CPU. Nvidia’s PureVideo HD is inferior to ATI’s UVD in this respect but that’s not a big problem. Our tests of these video-processors showed that the peak CPU load is not higher than 33-35% when processing VC-1 1080p content on either of them.

The improvements are available in the software, so all the new features in decoding and processing of video can also be used on Nvidia’s G92-, G84- and G86-based cards after you install ForceWare 174.x. First of all, the driver now supports simultaneous decoding of two streams to enable Picture-in-Picture mode.

Two more innovations are questionable. We mean the dynamic enhancement of contrast and saturation. The first feature corrects the contrast of the scene in a way similar to the Auto Contrast filter in Adobe Photoshop and ACDSee, but in real-time mode. The second feature adjusts the color saturation in skin, green, and blue tones. Are these features really valuable? In fact, they have something in common with the Creative 24-bit Crystalizer technology as well as with the Digital Vibrance Control option long available in Nvidia’s ForceWare driver. Processed with these technologies, the content does not resemble the original. If you enable these features, you won’t see what the movie director wanted you to see, for example. Fortunately, each feature can be turned off in the ForceWare control panel. Perhaps someone may like the more saturated colors, but most admirers of HD video will prefer the original colors, we guess.

The last change is the correction of a bug that would disable Windows Vista’s Aero interface when playing video in H.264 or VC-1 formats. We haven’t spotted this bug even before, though.