Weird Anomaly

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analoguesque

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Aug 1, 2004
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I'm not sure even how to descrive this, but does anyone have this anomaly on G4TechTV, particularly during Screen Savers?

The pixels "shake" or vibrate about once/sec. It is very noticeable when there is text or horizontal lines onscreen, otherwise it just kinda makes the screen a little fuzzy.

The only thing I could compare it to is the heat wave effect you get when looking across a tarmac on a hot day - just a lot faster!?

Sorry for such a lame description but it's not something I see on other channels.

BTW, I have regular DirecTV on a hi-def TV using S-video and a Samsung S4040R DVR, so no hi-def.

I'd appreciate any feedback on this because I'd like to know if it is the channel, or my HDTV. I never noticed this on my regular TV, but probably because it was so bad anyway.

Thanks
 
I'm definitely not an expert but here's my thoughts-

Every few seconds or so, your receiver receives a keyframe. It's a completely new frame of video, and then after that, only the changes in the video since that frame are sent. Because of this, the heat wave-like thing is just the variation between what changes your receiver has made to the video, and what changes the video has actually made between keyframes.

Although there are multiple explinations, this makes the most sense.
DirecTV's compression may be too high - Digital video is compressed by, instead of telling the receiver each change per each pixel represented, telling the receiver what group of represented pixels are changed (ie a blocky appearance if compression is too high). Therefore, when your video is "refreshed" with the keyframe, it has some variations that are updated.

I watch that show daily, and don't notice what you're saying about that channel specifically.
However, I watch on a DVR and on a 27" SDTV.

Also, this is just speculation, but DirecTV may give more video bandwidth to channels airing football than a low-rating talk show.
 
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