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Discussion Starter · #1 ·
NBC has decided to schedule L&O:SVU against NYPD Blue, making it impossible for me to watch both in HD. Since my TiVo is connected to my cable box and I can't receive NBC OTA with my current set-up, I used my Samsung SIR-T150 to watch NYPD Blue and TiVo'd L&O:SVU.


Since getting HD on cable 8 months ago, I almost never use the OTA tuner; I was on the verge of selling it. However, I noticed that ABC was considerably sharper out of the Samsung than through the cable STB (an SA 3100HD). It was actually quite nice.


I imagine that there are different methods for converting from 720p to 1080i. What are they are what are the various pros and cons? The cable box seems to noticeably soften the image when compared to the Sammy.
 

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you may be seeing the difference between QAM and VSB modulation (i.e. cable versus broadcast) or you may be seeing a different bit rate on cable versus the OTA bit rate. Many variables when comparing cable versus OTA.
 

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Spent a while comparing CBS HD via my set's built-in tuner and my 2000HD and current 3100HD outputs. The OTA 8VSB signal was always slightly crisper and better appearing because both converters had/have a slight milky haze that obscures higher-rez low-contrast details such as faint blue pinstripes in an actor's shirt. Can't seem to equalize images with set adjustments. Suspect it's the component output circuit. I'm hoping that if TWC rolls out the SA8000HD soon, this fog problem, noticed by others, will have been solved. -- John
 

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I don't believe the bitrate difference bug-a-boo--it requires one to believe that the cable companies decode the feeds and re-encode them in realtime at a lower bitrate, which would really make a mess of it. Just don't buy it. They dump the subchannels, PSIP and padding, but the payload of the main channel stream is intact.


Looking at it tonight, switching back and forth during part of "Threat Matrix", it does seem more likely to be an output circuit issue than anything. I can almost equalize them by adjusting brightness , but not quite. The PQ of one source versus the other is not nearly as desparate as I thought--on Tuesday, I couldn't compare, since I was using the cable box to record something else. Never mind.
 

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Quote:
I don't believe the bitrate difference bug-a-boo--it requires one to believe that the cable companies decode the feeds and re-encode them in realtime at a lower bitrate, which would really make a mess of it. Just don't buy it. They dump the subchannels, PSIP and padding, but the payload of the main channel stream is intact.
Not quite. There's a relatively new method called rate shaping to shrink bitrates that doesn't require decoding/recoding. See this post and its sublinks. -- John
 
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