What no one will tell you about HDTV...
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OMG! I thought this thread died months ago. Let's keep beating a dead horse to death some more.
Yes indeed. Otherwise we'd be all be watching SD and HD programs with little green specs all the time.
And HighDEFJeff, Have brought no proof of any kind, or have answered any valid questions on your claims. Everyone else has brought more info on the subject, then the guys who even started this subject. Digiblur knows what he is talking about . I can't say that about everyone but , He can back up anything he says and he has a earned a ton of respect. Not like some one else here that just decided one day to start a website and start running off at the mouth about something that can't and won't be backed up.
From HDTV magazine @ After-Purchase Hints and Tips
Picture quality
The image quality is not affected at all by a low to moderate level of noise in the signal. This is true for both satellite and OTA DTV. Yet some people can’t resist wondering “could I improve the image by improving the signal strength?” The answer is NO!
]When the signal becomes too weak, you will see “macro-block errors” (parts of the screen that are shifted or obviously wrong), sound dropouts lasting a few seconds, or image freezes lasting a few seconds. All of these errors are crude, unsubtle errors. If these are not present, your image is perfect.
If your image is perfect, there is still one reason you might want to improve the signal: It would make dropouts less likely in bad conditions, such as heavy rain. Rain can affect DBS and UHF reception, but not VHF. In some places, wind can affect UHF.
Picture quality
The image quality is not affected at all by a low to moderate level of noise in the signal. This is true for both satellite and OTA DTV. Yet some people can’t resist wondering “could I improve the image by improving the signal strength?” The answer is NO!
]When the signal becomes too weak, you will see “macro-block errors” (parts of the screen that are shifted or obviously wrong), sound dropouts lasting a few seconds, or image freezes lasting a few seconds. All of these errors are crude, unsubtle errors. If these are not present, your image is perfect.
If your image is perfect, there is still one reason you might want to improve the signal: It would make dropouts less likely in bad conditions, such as heavy rain. Rain can affect DBS and UHF reception, but not VHF. In some places, wind can affect UHF.
I told him that already http://www.satelliteguys.us/1197654-post105.html, but it came into deaf ears.
Is this a strange rewording of this earlier poll?
Not sure how you would answer it. Have lots of techs been told the picture is better? Yes, even if its not true.
And if your signal was so borderline that you frequently locked and unlocked they may even mean it.
Not sure how you would answer it. Have lots of techs been told the picture is better? Yes, even if its not true.
And if your signal was so borderline that you frequently locked and unlocked they may even mean it.
I think what it comes down to is techs are going out and relocating dishes that have partial obstructions that even though the signal may be adequate there is still enough blockage to throw the signal off balance so to speak.
One instance that stands out clearly for me with partial blockage involved a post mounted dish that I had put in wich had signals in the high 90's, two months later I go back and the signals are slightly down but still far above the minimum requirement. I went inside and noticed that the picture did look a little gritty and there was pixeling and some loss of a/v at times. Traced the lines and all was good so I looked at the dish and eyeballed the line of site and noticed that the oak that I felt I had gotten past might still have been an issue so after I checked and tried to retune the dish I went ahead and moved it forward. The signal strength remained the same but the pq was markedly better and there was no further pixeling or a/v drop out.
Other times where I've seen poor pq has generaly been related to damaged or cheap a/v cables to the television set while my favorite and more common than you would expect is home electrical wiring problems and grounding issues wich can and do cause problems relating to video and audio.
I've never seen a retune that made a picture look clearer though I have had many customers tell me how much better the picture looks when they've upgraded a dish or receiver though I never noticed a diference. 6 years of installs and never have I seen the pq change from %125 down to %50, its always looked the same.
One instance that stands out clearly for me with partial blockage involved a post mounted dish that I had put in wich had signals in the high 90's, two months later I go back and the signals are slightly down but still far above the minimum requirement. I went inside and noticed that the picture did look a little gritty and there was pixeling and some loss of a/v at times. Traced the lines and all was good so I looked at the dish and eyeballed the line of site and noticed that the oak that I felt I had gotten past might still have been an issue so after I checked and tried to retune the dish I went ahead and moved it forward. The signal strength remained the same but the pq was markedly better and there was no further pixeling or a/v drop out.
Other times where I've seen poor pq has generaly been related to damaged or cheap a/v cables to the television set while my favorite and more common than you would expect is home electrical wiring problems and grounding issues wich can and do cause problems relating to video and audio.
I've never seen a retune that made a picture look clearer though I have had many customers tell me how much better the picture looks when they've upgraded a dish or receiver though I never noticed a diference. 6 years of installs and never have I seen the pq change from %125 down to %50, its always looked the same.
Watch this all day instead of the picture perfect 50% signal HD.
[YOUTUBE]K80CIQPwruU[/YOUTUBE]
Thats kind of Funny. In a sick kind of way. Not enough blood though.Watch this all day instead of the picture perfect 50% signal HD.
[youtube]K80CIQPwruU[/youtube]
Okay I'm currently working on a PhD. in Computer Science. My area of research is in Video Compression. I do quite a bit with mpeg compression technology but more so with H.264. Mpeg4, mpeg2, H.264 are fundamentally more similar than different. I've even delved into the specific source code for these different implmentations. H.264 is open source by the way so if you're feeling bored it is available to anyone. Anyway it doesn't take a phd to figure out that the OP has no idea what he is talking about. As most have already said bit are bits, 1's and 0's. Mpeg in general divides the screen into many blocks. These blocks are also then subdivided into more blocks. If you loose any part of a signal you will loose some of these blocks, hence you see pixelation. You do not see a low grade representation of these missing blocks because that part of the information is lost. It is either there or not there.
Proof
I've offered much proof. Here's the government agency that has the task of figuring out picture quality:
The Institute for Telecommunication Sciences (ITS) Video Quality Research Video Quality Research Home Page
And,
"Picture quality in a compressed system can change dynamically based on a combination of data rate, picture complexity, and the encoding algorithm employed." comes from here:
Video/Imaging DesignLine | Measuring HD performance with Tektronix' Picture Quality Analyser and other tools
There are other proofs on the website. Everything I've said is backed up by links to the information and I have included a page of many of the resources that I've found informative. The science behind digital function and satellite systems is obviously not taught or well understood.
I've offered much proof. Here's the government agency that has the task of figuring out picture quality:
The Institute for Telecommunication Sciences (ITS) Video Quality Research Video Quality Research Home Page
And,
"Picture quality in a compressed system can change dynamically based on a combination of data rate, picture complexity, and the encoding algorithm employed." comes from here:
Video/Imaging DesignLine | Measuring HD performance with Tektronix' Picture Quality Analyser and other tools
There are other proofs on the website. Everything I've said is backed up by links to the information and I have included a page of many of the resources that I've found informative. The science behind digital function and satellite systems is obviously not taught or well understood.
JEFF,
You never did and never do answer these questions. You regurgitate theory and data, but so what? What difference are you making for any of us? NONE!
Apparently, this isn't enough anymore!Thats kind of Funny. In a sick kind of way. Not enough blood though.
OP dead wrong
AMAZING THREAD!!! Despite the fact that his poll got HAMMERED in opposition to his theory, he actually quoted the results as though they were in his favor! CLASSIC.
I don't imagine for a moment that I can convince him otherwise, but it does concern me that this type of misinformation is so vehemently defended. Granted, those who read the entire thread (like I just have) will see that there are enough seasoned professionals on these forums that gave excellent responses.
I consider myself to some extent one of those seasoned professionals, in that I've got over 2,000 installs under my belt. And here is my testimony:
75% signal strength will give the exact same picture quality as 100%
or for those weaker birds (such as 129) 50% signal strength will give the exact same picture as 70%. The Original Post and the Original Poster are simply dead wrong on this issue.
I've been to countless jobs where the customer does indeed complain about their Dishnetwork HD picture quality relative to OTA or other providers. We're talking hundreds of TV types, hundreds of receivers, and hundreds of cable types. On MANY of the jobs, there is simply nothing you can do for them. The signal strength is the EASIEST variable to check, and has almost always been fantastic. Increasing the Signal Strength did nothing for these customers.
Basically the problem with customers who complain about Dishnet HD picture quality (after unsuccessfully trying different receivers, cables, coax, TV's, channels, dishes) is the WAY DISHNETWORK CHOOSES TO COMPRESS THEIR DATA STREAMS.
Picture availability, stability, and reliability does have something to do with signal strength, but:
Picture Quality has Nothing at all to do with Signal Strength.
AMAZING THREAD!!! Despite the fact that his poll got HAMMERED in opposition to his theory, he actually quoted the results as though they were in his favor! CLASSIC.
I don't imagine for a moment that I can convince him otherwise, but it does concern me that this type of misinformation is so vehemently defended. Granted, those who read the entire thread (like I just have) will see that there are enough seasoned professionals on these forums that gave excellent responses.
I consider myself to some extent one of those seasoned professionals, in that I've got over 2,000 installs under my belt. And here is my testimony:
75% signal strength will give the exact same picture quality as 100%
or for those weaker birds (such as 129) 50% signal strength will give the exact same picture as 70%. The Original Post and the Original Poster are simply dead wrong on this issue.
I've been to countless jobs where the customer does indeed complain about their Dishnetwork HD picture quality relative to OTA or other providers. We're talking hundreds of TV types, hundreds of receivers, and hundreds of cable types. On MANY of the jobs, there is simply nothing you can do for them. The signal strength is the EASIEST variable to check, and has almost always been fantastic. Increasing the Signal Strength did nothing for these customers.
Basically the problem with customers who complain about Dishnet HD picture quality (after unsuccessfully trying different receivers, cables, coax, TV's, channels, dishes) is the WAY DISHNETWORK CHOOSES TO COMPRESS THEIR DATA STREAMS.
Picture availability, stability, and reliability does have something to do with signal strength, but:
Picture Quality has Nothing at all to do with Signal Strength.
Anyone want to tell my why there's a government agency working on digital picture quality?
Does no one check the links? Certainly you won't take my word for it...that's why I included links.
And, why would the engineer who wrote post #108 have anything to offer if I'm so off base?
The whole point of this is to get installers to realize that a low signal, high BER, and slow data can compromise picture quality, even digital.
So, what about The Institute for Telecommunication Sciences (ITS) Video Quality Research Video Quality Research Home Page ?
