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ATI and NVIDIA correct the twinkling effect of LCDs in movies
by Vincent Alzieu
Published on September 12, 2006

Graphic cards that correct the twinkling effect in videos
ATI and NVIDIA no longer only accelerate games, as video is now also one of their objectives. And if that wasn’t enough, they decided to improve its images. They are working on two aspects: the reduction of noise and reinforcement of edges. But first of all, why is it me who is working on this subject and not Damien or Marc our CG specialists? Well the answer is simple. It’s because it has something to do with our beloved monitors. We decided to take a practical point of view to decide, which one is better and what are the best adjustments.

To whatever format it is encoded, video is necessarily compressed. The level of compression varies and the image transfer rate also depends on this compression. With the H.264 format, chosen for the future HD-DVD and Blu-Ray, it is sometimes up to 25 Mbits/s. If your configuration is powerful enough, and in particular, if graphic acceleration is activated or that you have the right decoding codec, you will have a much more precise image, with a higher level of detail and more vivid colors…In brief, this is HD and it’s better than SD (we won´t discuss this now). Ok, it is more precise, but we continue to tell you over and over in our monitor surveys that there is still a twinkling effect, at least for most LCD monitors. It is sometimes so significant that some technologies are now infamous for their weakness in videos. We know in principle that if we choose a LCD PVA, MPA, ASV, TN or even worse, IPS, you will have to step back at least 1.5 or 2 meters to ignore the twinkling effects that exists in videos. The panel itself also increases this effect because of the dithering, the overdrive, or simply because of an imprecise command system… The only technologies spared are CRTs (tube monitors) and to some extent LCD monitors equipped with Premium-MVA panels manufactured by AU-Optronics (like the Belinea 10 20 30W, ViewSonic VX2025wm...). CRTs do not degrade the quality of video, while Premium-MVAs do in a slight way. Knowing that most monitor sales are now LCDs, and big ones (more than 19" for most of the users and more and 20" apparently for our readers), that videos are increasingly present on internet and that a growing number of us now use their monitor as an occasional TV, better video rendering via the graphic card can become a very good selling point, as good as a few extra "fps" percentage points.

Imagine that for the same amount of money as a normal card, a graphic card announces similar performances in games, HDCP compatibility to ensures the display of HD protected flows and a total absence of twinkling whatever the monitor technology is. Already, all fans of 23, 24 and 30 inch monitors should be interested, because up to this date (it will no longer be the case in a few weeks / months), there were only ISP or PVA panels in these sizes. These two panels are seriously affected by the twinkling effect.

To show the advantages and disadvantages of ATI and NVIDIA´s systems, we used a NVIDIA 7800GT with the drivers and an ASUSTeK ATI Radeon X1800 XT with the Catalyst 6.8. The first difference is that NVIDIA initially deactivates the acceleration option, and ATI has chosen to activate it from the start.

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