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I just got the latest issue of Sound and Vision at my office. In the letters section a reader perfectly described the DLP panning artifact and asked why it wasn't mentioned in a TV comparison done in a previous issue - "they've blurred on any kind of fast motion. For instance, when a football play begins, the distinct blades of grass become a green pond, and the numbers on the back of a jersey break up into square blocks."


The editor of the so called magazine had the nerve to tell him that it doesn't exist. According to him it must be a source issue - "the problems you describe are things we frequently see on HDTV programs, but they're usually caused by poor or overly aggressive digital compression on the part of broadcasters and cable providers - not by anything the TV does."


If an editor of an electronics magazine isn't aware of this panning artifact, what's the chances Joe Six Pack is. I knew that Sound and Vision and it's sister publication, Stereo Review were the audio equivalent of the National Enquirer, but I was shocked that the Editor would be completely oblivious to something that is well known to the videophiles on this site. While some of the artifacts he's seeing may in fact be due to video compression, I found it appalling to tell the poor reader he was out to lunch when in fact the Editor was showing his Video ignorance.
 

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Quote:
Originally Posted by gobrigavitch
...


The editor of the so called magazine had the nerve to tell him that it doesn't exist. ....
Yeah, I saw that. It totally blew their credibility. I'll never believe anything I read in that mag.


Then, in that same issue, they didn't have any comments at all about whether the Mits with the wobulated DLP chipset has any artifacts when displaying sources with resolutions other than 1080i. :rolleyes:


How can they spend an entire review of a machine with an oddball native pixel count and only look 1080i sources and never look at any DVD's or 720p material? :confused:
 

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It's most probably written by some newby summer intern, not the editor.

What I don't understand when I see videophiles jumping up and down on hearing higher contrast ratio or lumen output of DLP projectors when panning artifacts are ruining the show most of the time, be its a high speed action film sequence or a sporting event. These artifacts are not like rainbow effect that some see, some don't. I think TI's marketing strategy is no better than Bose's, telling us what the pictures are supposed to look like and depriving us from enjoying fast sports with its single chip DLP technology.
 

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Well... maybe, and maybe not. I was very interested to see that letter too, and while I agree that the editorial response commits a sin of omission, I'm not convinced the comments from the editor are really wrong, at least with respect to the "blurring" described. It's difficult to know for sure what the letter writer is seeing, but his description could very easily be ascribed to compression artifacts and not DLP dithering/panning artifacts. They tend to occur in similar places -- pans across a scene -- but IME it seems like the panning artifact is more likely to occur in a more uniform scene, i.e. sky, while the compression artifacts are more likely to be seen when there is lots of detail and small changes. The scenes described in the letter seem to fit the latter a little more than the former. Saying that "numbers... on a jersey dissolve into square blocks" sounds a lot more like compression than dither artifacts.


In fact, the editor's response that S&V uses only high quality sources in testing, in order to make sure that any artifacts seen are in the TV but not the signal, seems pretty reasonable. How many posts are there on the HDTV forums talking about over-compressed satellite and even cable HD signals? The letter writer was talking about sets he viewed in retail stores, so it's hard to know what the HDTV source was but either way, that's not likely to be a good quality signal chain.


I do agree that the editors lost some credibility in saying they could NEVER see panning/dither artifacts on DLP and referring to LCD response lag, but the rest of the response makes sense to me.
 

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On a Sony PJ watching football with D* as a source. I also see it regularly on my brother's CRT Hi-Def TV when watching HD football on D*.


If the editor actually said DLP motion artifacts like rainbows do not exist he is obviously wrong, but I agree with him on the text you quoted. The problems as described in the letter are "usually" a result video compression.
 
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