Originally Posted by HKemhorns
I don't think it's the source. I don't think everyone that's watching the Sunday night football game is seeing what I'm seeing. When I watch golf on my 26", the whole screen turns to macroblocking as the camera follows the flying golf ball. Do you see that?
People on some NBC affiliates are certainly seeing that. Of the network feeds, the NBC is probably the most sensitive to overcompression because of the way it is distributed to the affiliates (i.e. at 23-24Mbps MPEG-2 instead of 45Mbps MPEG-2).
Every broadcaster has 19.4 Mbps available to use. Some affiliates -- like CBS owned and operated stations -- devote most of it to their HD feed. Others divide it among several channels (weather channel, stock channel, news channel, etc).
High-definition 1080i episodic series generally look acceptable in 11-12Mbps. High-definition 1080i sports requires 15-16Mbps to look acceptable, and 18-19Mbps is needed to eliminate most of the artifacts during movement.
The problems you report are primarily seen with CBS and NBC affiliates that run two subchannels (i.e. weather and stock channels) and leave just 12-14Mbps to the HD feed. That may be acceptable for most series content, but sports can downright unwatchable at those bitrates. Some NBC affiliates clearly feel that having an extra weather channel is more important than having a watchable high-definition picture on Sunday Night Football and other sports.
It is possible that your cable provider is to blame (or at least, contributing to the problem). A number of Charter and Time Warner systems re-compress NBC and CBS HD to as little as 13Mbps. If that is true in your area, then you would get a better picture with an off-air antenna, or by switching to a provider that does not butcher their HD quality (like Verizon FiOS). With Verizon FiOS and some Comcast systems, the picture you get is 100% identical to what they receive from the affiliate (which can be good or bad, depending on how many bits they allocate to the HD feed).