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Discussion Starter · #1 ·
At 1920x1080i my HiPix exhibits a Moire effect on my monitor, which is normally not too annoying but really stands out in areas of solid color.


But worse, at 1280x720p I can clearly see a pattern dither, especially in areas of solid color. What's really bad is that this dithering seems to cut the horizontal resolution in half in many places. It's almost as if the HiPix uses video modes with 16-bit color, dithering the 24-bit color output from its MPEG-2 decoder.


I would like to watch shows in their native resolution, but with this dithering problem, 1280x720p content actually looks better displayed at 1920x1080i.


Has anyone else noticed the HiPix's pattern dithering? Does Telemann know about the problem and would there be any way for them to fix it through software?
 

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I have not experienced this with my HiPix.


Moire depends on your monitor...

Some monitors have "anti-moire" settings

that do some high frequency "jiggle" on the

scan lines to reduce Moire.


Unfortunately some monitors will show

some amount of Moire with signals of

certain resolution.


Personally I don't notice *any* moire on

my Sony W900 or Viewsonic P815.


It doesn't look like it "dithers" either.


Out of curiosity what kind of display do

you have?
 

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Discussion Starter · #3 ·
My display is a Sony GDM-F500. Only 1920x1080i exhibits moire, and the interlacing confuses my monitor's moire cancelling functionality -- odd and even lines go out of phase in their "jiggle".
 

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On my Sony W900 monitor I had to shrink the

image a bit (put a border around it on all

sides) for 1080i otherwise the interlacing

didn't line up correctly.


You might try playing with the sizing controls

(horizontal & veritcal) and see if doing

something less than full screen actually

helps with the moire and interlacing artifacts.


I think you will find that as you "squish" the

image, the moire will "move around" and some

settings may be more pleasing than others.
 

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I'm using my HiPix with an RPTV HD set and there are no moire problems. I suspect it's related to your shadow mask and the size/position of the scan lines.


I haven't tried it on my 21" ViewSonic, but I know that the monitor has settings to reduce the moire effect. If you monitor has that option you might try it.


Rick
 

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I've seen no moire patterns on my sony FW-900, but I have seen momentary conversion of reds to a fine red checkerboard pattern on upconveted NTSC. I suspect this is the broadcaster though.
 

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Discussion Starter · #7 ·
First of all, let me say that the moire is not the real problem I am concerned with. The dithering is what bothers me. At 1920x1080i, it results in some moire for me but the picture looks fine otherwise. At 1280x720, this dithering interferes with the horizontal resolution -- in many places, it looks almost as if it is being cut in half (transitions between color seem to be confined to every-other horizontal pixel).


PVR, I addressed the interlacing problem in another post , and that is an entirely different problem from that which I brought up in this thread. FWIW, no amount of adjustment on my Sony GDM-F500 gets rid of it.


cpto, my "shadow mask" (it's actually an aperture grill) is entirely irrelevant. Without dithering, there would be no moire. It's the dithering and the granularity of my monitor's RGB stripes which interfere to cause the moire. And as for adjustments to reduce the moire, I already said what happens when I try that; interlacing confuses my monitor's moire-cancelling, making alternating lines jitter out of phase.


DAP, I strongly doubt that a pixel-grained checkerboard pattern could be encoded in an MPEG-2 stream. If I am wrong, somebody please correct me.


I am not surprised that nobody sees moire on the FW-900. It's wider than my monitor, and the pixels at 1920x1080 are probably wide enough that they do not interfere with the aperture grill enough to create noticable moire.


But, if I can clearly see the HiPix's dithering on my monitor at 1280x720, you should certainly be able to see it on the larger FW-900! I'm very surprised that nobody has written yet saying they see it. Please take a close look and tell me again you can't see it. It should be easiest to see if you pause a playback and look in areas of gradually shaded color.
 

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I scruitinze my HiPix image quite a bit

and notice NO "dithering" on 1080i HDTV images.


I suppose your HiPix could somehow be "different"

but that seems unlikely.


Just as a sanity check:


1> You are watching HDTV channels (ATSC 1080i)

right, not analog NTSC, or 480p that has been

scaled up by the HiPix, right???

(I suppose being in LA you could watch KCBS

primetime, KNBC tonight show, or KCET)

2> You see the same "problem" on all channels

that you tune, right???
 

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Discussion Starter · #9 ·
1> Yes, I am watching ATSC.

2> I see the dithering on both 1920x1080i and 1280x720p, no matter what I am watching, be it native 1080i, 720p, or even scaled-up 480p or 480i. I get KCBSDT, KNBCDT, KABCDT and KCETDT, as well as others that have no HD content.


The only sign of dithering at 1920x1080i is the moire I see. I am not surprised that you do not see dithering at this resolution, since the only reason I see it (as moire) is that my monitor's aperture grill pitch and the 1920 horizontal resolution are close enough to interfere.


But would you see if you can find any dithering at 1280x720p? I can quite clearly see the dithering at this resolution, and all I have is a 21" Sony GDM-F500. A larger display should only make it easier to see.


The dithering at 1280x720p is important to me; I would like to watch ABC at its native resolution, but due to the dithering, it actually looks better scaled-up to 1920x1080i. I'd rather not have to scale it like this! It totally defeats the purpose for which ABC uses 720p in the first place.
 
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