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Cablevision. The other HD signals are great. Just HBO is awful.
They may have squeezed HBO in with some other channels.

Cable providers like Cablevision have 38.8Mbps available per QAM slot. As distributed by satellite, HBO, Showtime, and Starz all require 10-11Mbps average and about 14.5Mbps peak (i.e. during action).

The bean counters at cable companies think it is wasteful to stick HBO and SHO on one 38.8Mbps QAM channel, because that only uses 20-22Mbps average and 29Mbps worse-case. The remainder of the 38.8Mbps is unused.

A number of cable providers, including Cablevision, Cox, and Time Warner have installed rate shaping equipment to squeeze a third channel -- say, HBO, SHO, and Starz -- into the same 38.8Mbps QAM slot. When one of those channels need more bits -- such as during action or movement -- pixelization and blocking results because the needed bandwidth isn't available. In this case, the provider has prioritized quantity over quality.

I suspect Cablevision added new HD channels at around the same time this problem began.
 

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Discussion Starter · #42 ·
Just to give an idea what it looks like at my end... here are two screenshots from tonight's "My name is Earl" (click to see higher resolution).

The one that looks like crap is while the camera pans up. Notice that even the channel bug gets pixelated!

The one that looks fine is when the camera stopped panning. This is how it is for virtually every shot that pans, especially if it's lot's of color for some reason - NFL games look like crap.

I think I might send these screenshots in my e-mail to the guy at the local NBC affiliate...



 

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FYI, NBC is the WORST example of HD. Ever. Just horrible. Ghastly. If you want to compare cable vs. OTA networks, try CBS for 1080 or FOX for 720.

As for HBO and other premium channels, the quality is often limited by the source material. The endocing on Blood Diamond, for example, looks as bad as live football on NBC any time there's action on the screen. If the studio does a poor job of encoding the movie, it doesn't matter how much bandwidth HBO or the carriers provide. Crap in = crap out. That makes HBO et al a less than ideal choice for judging the quality of your HD signal. It's difficult to determine where the quality was lost. It could be perfect right up to the cable company or it could be bad at the source. The end result looks the same.

With the networks, at least you know that the network had significant input regarding the quality of the source material. Especially with live sporting events where they control everything starting at the camera, ending with the local affiliate.
 
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