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Distorted or "pixelated" faces

3K views 7 replies 3 participants last post by  Sammy2 
#1 ·
I'm not even sure what to call this since pixelation is also an art form in some circles.


My HTPC is a new Asus running W7 on an AMD Phenom X6. Ceton board with Motorola M-Card tuner.


Occasionally the video gets all pixelated for a few frames. This happens more often (but not always) on faces when they're in motion. Looks like this:




Signal level and SNR look good, so I'm thinking it's related to a CODEC or some other processing element.


This is the signal level right after the screen shot was made:




It's certainly not a show stopper, but it would be nice to make it stop doing that.


Any ideas?


Thanks in advance.

Art
 
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#2 ·
It could be the incoming signal from your cable co. What I would do is note which channels are macroblocking and write down the frequency that the channels are on. Give that list to your cable co and the tech can do MER and BER tests on those QAM's to see if they pass or fail.
 
#3 ·
I should have mentioned that I have never noticed it on the other TV set which is connected to the same cable service via a BrightHouse-supplied splitter and set-top box. I will get some more data.


Thanks for the new word--macroblocking--for my lexicon.
 
#5 ·

Quote:
Originally Posted by NoMoTBCs  /t/1416747/distorted-or-pixelated-faces#post_22155119


I should have mentioned that I have never noticed it on the other TV set which is connected to the same cable service via a BrightHouse-supplied splitter and set-top box. I will get some more data.

Thanks for the new word--macroblocking--for my lexicon.


Good to know other leg off the split is good..... still does not rule out the possibility of a failure on the leg to the HTPC. Could be as simple as a bad connector. Just FYI, in my cable system we would not be hitting a set top box or QAM tuner @ 13.3db...... it would be 6-8 db less. That does not mean that your levels are wrong they may be within spec for your cable system.
 
#7 ·

Quote:
Originally Posted by NoMoTBCs  /t/1416747/distorted-or-pixelated-faces#post_22155119


Thanks for the new word--macroblocking--for my lexicon.

I was searching for "Macroblocking" and came across a thread on another forum suggesting that it may be the HDD having trouble keeping up with the data in a quickly-moving face. ("Live" isn't live, of course, when a DVR is involved.) I thought this was interesting. My other forays into HTPCs did not involve HD and this new one doesn't have a special HDD. Maybe I should have looked closer at that.


(I'm not sure about the customs on this forum concerning references to other forums. If someone would like the URL of that discussion, PM me, or if a moderator will let me know it's OK here, I'll add it.)


Art
 
#8 ·

Quote:
Originally Posted by NoMoTBCs  /t/1416747/distorted-or-pixelated-faces#post_22155906


Two or three times a day at the most.

That's a bit annoying. Seems to be that something in the chain isn't keeping up, including the signal from your provider.
 
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