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Hi,


I have a panasonic TX-P42U20e connecting via HDMI on my PC. I noticed when reading red text on a dark background that the text is all garbled / scrambled. The pic below shows the problem that only exists with this color combination and only with text. I've tried another videocard / HDMI cable (ATI & Nvidia) but the problem persists.




Is this normal for plasma's connected to a PC or is there a solution?
 

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The human eye cannot focus on red and blue at the same time.


See the section "Blue Text on Red Background and Vice Versa" at this link here for an example.
 

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Quote:
Originally Posted by tomwil /forum/post/20143202


The human eye cannot focus on red and blue at the same time.

I'm sorry but this isn't the issue.


When my PC is connected to the TV via VGA rather than HDMI, the issue is no longer there and the red text is perfectly crisp. However using HDMI is when these problems arise.
 

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Does the issue occur with other HDMI sources (such as a blu-ray player)? If so, the issue is within the TV. If not, the problem would seem to be within your computer/GPU.
 

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Apparently it has something to do with Chroma Subsampling? It happens when the graphics card identifies my TV as a HDTV and does some things to make the image better, but just messes it up.


Hmmmm D:
 

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Yes, I saw this is in completely unrelated thread here on AVS and that is the problem. Just search this site for chroma subsampling and you should be able to find it. The problem occurs either when the source is outputting at 4:2:2 (this is what is happening with the GPU HDMI output) or the TV does not properly do 4:4:4.


Additional reference:
http://en.wikipedia.org/wiki/Chroma_subsampling

Quote:
Originally Posted by thepoohcontinuum /forum/post/19723268

4:4:4 Chroma Subsampling


“Chroma subsampling” is a video compression technique used to reduce the bandwidth required for transmitting digital imagery data. This is accomplished by “merging” the colors of neighboring pixels into one. In terms of actual TV picture quality, areas with two neighboring colors (especially red) will seem blurry and fuzzy without proper 4:4:4.


4:4:4 support is better described in pictures than in words, so check out these 4:4:4 test results: link1 and link2 . The first one is the LG 32LD450 and the second is the Sony 32EX500. On the LG, all the vertical red lines are perfectly represented as a single column of red pixels. But on the Sony, the vertical red lines are represented as alternating columns of pure red (correct) and “faded” red (incorrect).


There are *very* few LCD TVs that can fully support 4:4:4 chroma. Colmino did an extensive search for 4:4:4 capable TVs, and hardly any were found. You can see his results here: link . Since most people have never seen full 4:4:4, they don’t know any better. But once you’ve seen 4:4:4 with you own eyes, you won’t accept anything less
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Note1: 4:4:4 support is generally only important for PC connections and game consoles. Pretty much all HD media (including bluray) is already subsampled down to 4:2:2 or lower.


Note2: For clearer and bigger 4:4:4 test results, see zoran0909's results ( link )
 
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