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Discussion Starter · #1 ·
I just noticed that when I watched the Flyers game tonight on CSN-HD channel 172 on Comcast cable here in E-Town, PA something was a little weird.


The broadcast wasn't an HD source, since they were away from the First Union Center with no HD cameras, but it was, or at least I thought, an up-convert. Meaning that they take their SD camera's signal and pass it through a professional quality up-converter/scaler and output a 1080i "psuedo" HD picture to the masses down stream.


Well, I didn't like the quality of the up-conversion because it was filled with stair-stepping, combing, interlaced artifacts, digital artifacts, aliasing, etc. All the things you'd expect from an inferior scaler built into a consumer box, NOT from a broadcast quality up-converter like a Snell & Wilcox, Rhode and Schwartz, Teranex, etc. (I know, I am in the broadcast world in my "real" job;))


So to make a long story short, I went to the system menu of my Motorola DCT-5100 and switched the "480 Override" option to 480i (thinking I had to do this to activate the analog video outs, since I never usually use them) so that I could send the output to my T A W Rock+ processor to clean up the image I was getting.


Well lo' and behold, it turns out that all the other HD channels come out as 1080i, even if the original show is SD and then up-converted, but CSN-HD was coming out of the component outs at 480i:eek: It seems they just do CSN-HD like any other digital SD channel and let the box do the upconversion to 1080i (when override is set to off) instead of doing it there in the Head-End like other broadcast HD stations do it. A cheap and low trick in my book:mad:


So it looks like the only time your 5100 is getting 1080i through the cable is when the source is actually 1080i HD, like a live sporting event!!! Any other time it's just plain old vanilla 480i that the cheapo up-converter chip in your 5100 box is scaling to 1080i, just like for C-SPAN 3:(!!!


Can someone else confirm this, or has this already been discussed and I missed it before???
 

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Dave,


It's well known the only HDTV on CSN is the live games. See the CSN schedule links in the HDTV Programming Synopsis for details.


It sounds like they don't upconvert non-HD at the source, if when the games are not on, you only get 480i.
 

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Ken is right/ When Comcast is not doing the games in 1080i, it sends out a 480i signal on 172. Check out the next HD game. As soon as the game is over and they go the Post Game Live, the signal swithes to 480 i. The switch is unmistakable.
 

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Dave,


The switch is really unmistakeable. I had to turn off the 480 override to avoid having to reacquire the picture after the switch. Before, I would notice the switch when the picture would shrink to about one-ninths size and occupy just the upper left corner of my screen, necessitating a quick channel up and down to reacquire the picture. With the 480 override turned off, I notice a little hiccup in the picture.
 

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Discussion Starter · #5 ·
Thanks Guys:)!!! I didn't know that.


I just got my 5100 and CSN-HD right before I left for the desert. I didn't have time to go back and read everything about this, and I didn't hear it mentioned in anything I read so far, so I was pretty astonished and curious when I noticed this after I returned.


That kind of pisses me off though. They should have a broadcast upconverter at the head end instead of relying on that cheap chip in the 5100:(!!!


Thanks again and..."NEVER MIND";)!!!
 

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Quote:
It sounds like they don't upconvert non-HD at the source, if when the games are not on, you only get 480i.
The advantage to upconverting to HD at the source is that they probably have a better scaler than you or I do. ;)


But the disadvantage is the extra bandwidth it wastes that could go towards a better 480i digital picture plus extra bandwidth for the other channels. And there really no extra info in the picture after the upconvert.


A really good compromise would probably be to use the good equipment to convert all SDTV camera stuff to 480p @ 24, 30, and 60 FPS in the digital domain, properly flagged as needed, and let the STB's handle it from there.


This would be harder for OTA TV since the boxes maybe are or aren't standardized to that level but any cable company could handle it and save a lot of bits because they still have control over which STB's are being used for HDTV.


- Tom
 

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It's nice that they don't upconvert, because then my tv can stretch the picture so there are no side bars. It's much better than the analog channel for SD broadcasts, so be happy they do it that way is what I say.
 

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here in DC all we get is a Schedule on 172 when there are no HD games to show. They dont have their regular schedule on it at all...
 

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Originally posted by drhill
It's nice that they don't upconvert, because then my tv can stretch the picture so there are no side bars. It's much better than the analog channel for SD broadcasts, so be happy they do it that way is what I say.
You're right, I like having the ability to do what I want with the SD signal when they are showing an away game. I also agree that when the games are in SD, the picture quality on 172 is wayyyy better than the regular channel.
 

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I too like the ability to handle the SD broadcasts locally and let my TV do the picture formatting.


Of course, this is only short-term. When the permanent HD control room is finished at the First Union Center, I expect that all of the broadcasts will be in HD.
 
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