HD PQ for primetime Network shows - facial artifacts (or microblocking)

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Pakbackr

Pakbackr

SatelliteGuys Pro
Original poster
Aug 28, 2006
382
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Fuquay Varina, NC, United States
I recently upgraded to a 58 Samsung plasma, 1080p...one very nice TV. I have, however, noticed a huge variation in HD PQ from channel to channel with this set, seeing facial artifacts (or microblocking) that I never saw with the old Panasonic 720 dlp. This problem seems to be most prominent on the major network (ABC, CBS, NBC) primetime shows like Big Bang Theory, Two and a Half Men, 30 Rock, Modern Family, etc. I see similar PQ via the OTA channels, and both live and DVR'd shows. Its not unwatchable, but definitely not the crispness you would expect (and actually get on most programming). Just wondering if anyone else has experienced this? And any thoughts as to what is causing this?
 
Do you see this from a normal viewing distance? I can find compression artifacts in almost all compressed video if I closer than normal to the screen. It may be your local channels. Are they transmitting sub-channels? In general I have found that OTA network broadcasts have fewer artifacts than most cable/satellite channels. Reducing the sharpness/detail on your TV slightly may make them less visible.
 
What size was the Panny? If you went from a 40" screen to a 58" screen, it could just be that you had not noticed it on a smaller screen. You will notice more artifacts on a larger screen.
 
The Panny was a 50 inch, just a little smaller, but also it was 720. And settings have been tweaked off of vivid and onto normal. I used calibration settings I found from one of the test labs. So, no one has said yet if they see similar artifacts...anyone????
 
You went 8" larger and to a finer resolution so you will see compression artifacts the closer that you get to your TV that you did not notice before. Try the built in tuner to see if it looks better than the DISH box that you are using.
 
jayiw said:
You went 8" larger and to a finer resolution so you will see compression artifacts the closer that you get to your TV that you did not notice before. Try the built in tuner to see if it looks better than the DISH box that you are using.
Click to expand...

Good suggestion. If straight OTA feed looks noticeably better, do you think it is an issue with that particular box or am I likely to have the issue with any Dish HD receiver?
 
FWIW, I see no artifacts or macro blocking on my 60" 1080p tv on static images besides a tiny amount of mosquitoing around text. But I had to turn off all enhancements and effects in my tv's settings to get a clean image (sony in my case, not samsung). I can switch from OTA to Sat and I see absolutely no difference. I see some macro blocking on fast motion, but it's the same as on OTA. This is on a 722k with an OTA module. I'd say get a calibration disk and make sure your tv is set up properly. You can make your own for free from avsforum.com.
 
What network/networks does the macro blocking occur? In most cases that's caused by an encoding error from the broadcaster, ussually over compression. Are any of your locals multicasting? Does the macroblockin all the time or only on sports?:D
 
toto said:
What network/networks does the macro blocking occur? In most cases that's caused by an encoding error from the broadcaster, ussually over compression. Are any of your locals multicasting? Does the macroblockin all the time or only on sports?:D
Click to expand...

Per original post, this problem seems to be most prominent on the major network (ABC, CBS, NBC) primetime shows like Big Bang Theory, Two and a Half Men, 30 Rock, Modern Family, etc. They all seem soft and I see the facial pixels change even if characters are not moving.
 
I've see a similar effect on LCD TV's (I've never watched a plasma long enough to notice). To my eyes, it's almost a color depth issue, where you can see a discrete jump from one shade to another, rather than the smooth transition you'd see if the color depth were greater. I have neither LCD or Plasma, so I don't see it on my TV. I wouldn't expect such an effect on plasma. Have you noticed the same thing on blu-ray?

As far as networks go, the Tonight Show on NBC has just about the most perfect picture I've seen. Do you see the same effect there, and can you compare it to OTA? I recorded both when I first got Dish to see if I could detect "HD Lite". I couldn't see any difference, and definitely don't see what you're describing.
 
I see artifacts in ALL broadcast content, just the nature of the beast. Not enough bandwidth with current standards. Blu-Ray is the only way to get a near artifact free picture.

To the OP, an 8" larger picture is a huge difference. So you just didn't notice it before. Screen size, viewing distance and your eyesight determine your PQ. So it is more obvious to some that others.
 
Welcome to my world. I've been upset for quite a while now on the quality of HD video, which has actually gone down since I first got set up in 2004! I spent a lot of money upgrading my equipment so I expect to get better quality video than what we're getting. Quite a lot of times the quality is so bad I think I'd prefer an anamorphic DVD.

I see compression artifacts on all HDTV channels, OTA or on Dish. Its just a matter of over compression. OTA TV uses MPEG-2 compression, each ATSC channel has about 19Mbps of bandwidth, which is enough for pretty good video quality. 3 of the 4 major networks (what you see ota from FOX is what FOX's headend sends out) use a system in which they deliver a very high bandwidth signal to their affiliates, which in turn re compress it to fit into one ATSC channel. The problem is many stations don't use their entire bandwidth for one channel, they want to cram in an SD (or sometime an HD) subchannel for a bit of extra revenue. That severely degrades the picture quality. Another issues is, for some reason some of the stations in my locality don't use their entire bandwidth. CBS(KRQE) here broadcasts at 17Mbps even though they have no sub station.


Dish uses h.264 compression which is much better than MPEG-2 but they're cramming in 8(!) HDTV channels per 40Mbps transponder. Thats roughly 5 Mbps per channel, which isn't anywhere near enough for 1080i. For comparison, Blu-ray discs generally average around 30Mbps or more for video. As far as your locals go, by the time you see it on Dish the program your watching has already gone through compression at the network, then again at your local affiliate, then yet again by Dish. Dish's HD locals look much softer to me than from over the air.

I have two ways of watching HD. One on my 42" 720p Panasonic plasma. Some channels from Dish look OK on it, others are pretty much unwatchable. The other is a 24" Dell Ultrasharp 1080p monitor, pretty high end. I can't hardly stand watching Dish HDTV on it when sitting at my desk. For some reason Plasma TV's do better than LCD's with poor quality HD, also 720p sets look better as well, someone else smarter than me can probably explain why. You also need to take into account your viewing distance versus the size of your TV. I'd suggest turning your sharpness all the way down, and tweaking the contrast down some as well.
 

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