De-Interlacing Approaches

Weave

Weave is easiest to understand. You just decide to display both the odd and even fields at the same time. This makes sense because you are getting full-resolution playback and indeed this is a very good approach for most DVD movies. So what's the limitation?

Imagine if you're moving so fast that you're in one place when the odd lines are drawn and by the time the even lines are drawn, you've moved over 1 ft. Now, the image on your monitor contains half of you in one place, and half of you in another place.

So basically, with weave deinterlacing, scenes with a lot of horizontal motion have feathering artifacts.

Bob

Bob was designed to address feathering problems. In the first split-second, you can just draw the odd lines twice and in the second split-second, you can draw the even lines twice.

This gets rid of the jaggies, but now the problem is that you lose a lot of your resolution and for non-moving images it actually looks worse than weave since you may get an odd "bobbing" effect where horizontal lines vibrate up and down.

The Solution: Adaptive Deinterlacing

ATI saw this problem in the Rage128-era and the best they could come up with was "Smart Select" technology. With Smart Select, the Rage 128 essentially switched between bob and weave on-the-fly.

For every scene, ATI would choose the best deinterlacing technique. This was okay, but far from perfect. Sometimes there would be one fast moving object and ATI would select bob whereas the majority of the scene would have looked better in weave.

Adaptive Deinterlacing, an ATI exclusive technology in the Radeon 256, takes the idea of "smart select" but takes it a step further. Rather than analyzing each scene frame by frame, the algorithm to be used is processed pixel-by-pixel.. It'll be interesting to see how well this feature works in real-life, but these images from ATI certainly look great:

More Detail

Slow down!

There's no doubt that the ATI Radeon 256 marks the next step in the evolution of video and multimedia performance. It first adds true HDTV support including 1080i and 720p output and also offers excellent DVD playback on the monitor.

Still, as exciting as the video portion of the Radeon 256 is, all this talk can be a bit confusing if you're not already familiar with the principles of HDTV. Fortunately, the GXNetwork has the solution for you: GadgetSquad. You'll find reviews and editorials on the latest consumer electronics as well as easy-to-follow guides and tutorials, including HDTV 101/102. Although we are not officially affiliated with FiringSquad or GX Media, GadgetSquad is part of the GXNetwork and you'll also find some familiar names there.