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Topic: pixelation
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Joined: Mar 29, 2005
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Is it me or does every HDTV have pixelation issues? It seems that every unit I look has a problem with pixels "globbing" during high speed sequences. I've wondered if maybe it was the source that casues it?
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Well the easy and obvious answer is no, they don't all have this problem.

What projectors are you viewing, and from what distance? Are they all playing the same source?
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Are you using component or DVI/HDMI?
Joined: Mar 28, 2005
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Yes, you will almost always see pixelization with sports or fast paced material with HDTV. It is less of an issue with SDTV, but with SDTV you wouldn't notice anyway because the image is so much worse.

The issue has to do with the encoding format: MPEG2 and the encoding bit-rate - 20Mbs.

As technology pushes forward we will see a technological shift towards MPEG4 and perhaps higher bandwidth. But, even with the same amount of bandwidth, MPEG4 will provide a much sharper, less pixelated image for the money.

Both HD-DVD & Blu-Ray Disc include MPEG4 in their white papers for player acceptance requirements.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.
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Pixelation also has to do with you projector's native video chip format versus the broadcaster's HDTV signal format. Some broadcaster's send 1080 lines of interlaced programming, other send 720 progressive. If you have a 480 machine (great for watching 99% of DVDs out there)and it is trying to down convert either one of these higher resolution signals, you will probably get pixelation from the interlaced broadcast signal.

The reason is simple. A digital projector shoots one frame at a time. Each frame of video "progresses" one after the other. Most CRT TVs have two frames "interlaced" together. This was originally done back in the 1950s to get more picture out of the limited bandwith they used to broadcast with. If your projector is a true High Definition "native" (meaning its video chip doesn't have to down convert HDTV broadcast signal to a lower resolution) pixelation should be very minimal if not eliminated all together. But even a 720 HDTV machine may get some pixelation if it is trying to down convert very fast 1080 interlaced HDTV signals. Of course, you could just switch to your "S" video input and now worry about HD for that one particular event.

PS, Fox broadcasts its HD signals in 720p specificaly to rid the viewer of nasty pixelation when using a native 720 unit. Thank you Fox.