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Picture Quality in QAM vs. STB

post #1 of 6
Thread Starter 
I just bought a 50" Panasonic PZ77 and the HD picture via QAM looks horrible. There is macroblocking at every scene change and during all fast movement. Watching a football game is terrible. I have a 26" HD CRT in my bedroom that I watch the same way and I had noticed this before, but I think because of the small size, it's not nearly as noticeable. I am planning on ordering a HD DVR STB, but if it's going to look like this, I'm going to satellite. Do STB's use the same signal that a QAM tuner uses? or can I expect it to look better?
post #2 of 6
The problem is probably with the source. If it's there fromthe broadcast, it will be there from satellite also. I have FIOS and had Comcast. They both broadcast exactly the same thing as the local station. If the macroblocaking is there oTA it is also there on Comcast and FIOS. Satellite will be the same also since there feed wouldbe the same. DirecTV justs converts the MPEG2 to MPEG4 before transmission.
post #3 of 6
Thread Starter 
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? I haven't watched sports at anyone else's home that has my cable provider, but I've watched plenty of HD football games other places and I've never seen anything like I see tonight. I'm pretty sure my cable company is the culprit. What I want to know is if I would be getting the same PQ from a set top box?
post #4 of 6
Quote:
Originally Posted by HKemhorns View Post

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).
post #5 of 6
STBs' from the cable company are usually worse than your sets' internal tuner, at least as far as the overall PQ goes (not relating to xmission issues).
post #6 of 6
Thread Starter 
Wow bfdtv, thanks for that detailed answer!

I'm sure that's some of it, but I still believe that my cable system must have done some extra compression. I frequent football message boards and would expect to read comments from others, if their PQ was as bad.

I did order a DVR STB today, so we'll see what difference that makes. The lady assured me that it would be better, [sarcasm] and she sounded so convincing[sarcasm]. She did say she'd have an engineer call me, but I'm not holding my breath. This is the same company that has told me on 4 or 5 occasions that they were going to change my cable modem, only to receive a message that they can ping my modem, so everything must be fine.
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