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Guest Message by DevFuse

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I deliver and install TVs. I have a question about SD picture quality on HDTVs


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26 replies to this topic

#1 OFFLINE   yooper99

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Posted 16 January 2009 - 05:44 PM

Being a TV installer, I have seen all the variations in cable boxes, all the different hookup possibilities, and all the differences in picture quality between the SD and the HD cable channels. The few DirecTV receivers I have hooked up are all SD boxes using the video output to some 1080P and 720P LCDs and a 720P plasma or two.

A question: Why does an SD signal from an SD receiver ALWAYS (in every installation with a standard receiver using video cables) look worse on the new HDTV than the old CRT that is being replaced? (with either an LCD or plasma)
No amount of tweaking can bring the picture up to the quality of a CRT. Now, before you start with the BS about not knowing what I am doing, I have had both the boss and the head technician from the store go to several of the installs and try to improve the picture. There is no improvement when they have tried.

I am looking for serious input. Thank you in advance.

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#2 OFFLINE   Jeremy W

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Posted 16 January 2009 - 05:54 PM

Why does an SD signal from an SD receiver ALWAYS (in every installation with a standard receiver using video cables) look worse on the new HDTV than the old CRT that is being replaced?

That old CRT was designed to display SD resolution natively. In order to display SD on an HD display, it needs to be upscaled to the display's native resolution, which involves the TV basically "guessing" at the missing pixels.

#3 OFFLINE   mikep554

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Posted 16 January 2009 - 06:33 PM

Also, if the picture is physically getting larger (60" HDTV vs 32" CRT), the flaws will be a lot more clear.
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#4 OFFLINE   MountainMan10

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Posted 16 January 2009 - 06:37 PM

An HDTV will never look as good as an SD TV with an SD signal.
Standard Video - Yellow cable - not even close
S-Video - on my 32" Samsung HDTV it is close to an SD TV.
480i on HDMI on my 46" Sharp - close to an SD TV
480p on HDMI on my 46" Sharp - a little better than an SD TV on DirecTV signal, significantly better from Bluray playing a DVD.
720p/1080i/1080p - many times better than SD TV.

#5 OFFLINE   bonscott87

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Posted 16 January 2009 - 06:48 PM

Garbage in/garbage out basically.

#6 OFFLINE   kikkenit2

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Posted 16 January 2009 - 06:50 PM

Yooper, do me a favor. Anytime you connect directv equipment to a new widescreen tv let the customer know they need to upgrade their sat hardware and yes it costs extra.
You are doing a better job to tell the truth and your clients will appreciate the fantastic picture. There are proper adjustments to the tv setup but they should be done with a hd source.
SD will never look that great on a flat tv. Don't sweat it. ;) Thanks

#7 OFFLINE   yooper99

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Posted 16 January 2009 - 06:53 PM

The table from MountainMan10 leads me to another question.
If a DirecTV customer upgrades to an HD receiver and uses HDMI to connect to the TV, will the SD channels come close to the old CRT picture? I am guessing that the HD receiver will supply a 480i picture for the SD channels. I realize that many of the regular channels are using very old content and nothing can improve the old films.

Since the HDMI cables are digitial only, then the SD feeds from the satellite are not subject to digital to analog conversion in the receiver and are sent to the TV with only the necessary decompression by the receiver. One less conversion can only help preserve some of the picture quality on the SD channels.

#8 OFFLINE   yooper99

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Posted 16 January 2009 - 07:03 PM

Kikkenit2, our store personnel always try to get your point across to the customers. It is amazing, though, to see how hard it is to get a customer to look at the "regular" channels and to pay attention to the warnings and info such as yours. They are mesmerized by the likes of PBS in HD and always want to switch back to the HD program.

It's only in their house without the HD channels, they ask where the great pictures went. Some people do listen but many don't hear a thing when the HD is jumping off the screen at them.

#9 OFFLINE   BattleZone

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Posted 16 January 2009 - 07:06 PM

For SD, HDMI or Component won't matter a bit.

There's simply no getting around the fact that standard-def programming has, at BEST, 1/6th of the information that you get with a 1080i signal. With DirecTV, it's actually less, as DirecTV's SD is downscaled to 480x480 resolution, so really, it's closer to 1/8 the data. That should help you put things in perspective.

Then, you're taking that tiny amount of data and stretching it across what is always a much larger screen. Here's a good analogy: try taking the amount of frosting you'd use for a cupcake and try to cover an entire cake with it. That's about what's happening with SD.

SD resolution was really never meant for TVs larger than about 25" in diameter, and up to that size, SD looks fine. With analog CRTs, which have problems but also have one great strength, which is scaling, we were able to get CRTs as large as 40", though most commonly the upper limit was 32", and at 32", you could definitely see artifacts.

Now take that same image and stretch it across a 52" TV and no surprise, it looks like crap.

Finally, virtually all HDTVs are fixed-pixel displays, meaning the actual display is made up of a fixed number of pixels that can't be changed (1920x1080 or 1366x768). CRTs, being analog, were never set at a specific number of pixels. The point is that SD content has to be digitally scaled up to fit the native resolution of the panel. What the scaler attempts to do is "guess" at what all those missing pixels are supposed to be. Imagine trying to read a letter with 7/8 of the characters missing: not so easy, is it?

As kikkenit2 said earlier, PLEASE encourage your customers to upgrade to HD receivers. Let them know that they are "enjoying" 1/6 to 1/8 of the picture information that their TV is capable of, when they could be enjoying ALL of the information for many of their channels. Everyone will be better off.

#10 OFFLINE   ThomasM

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Posted 16 January 2009 - 09:09 PM

This is a very interesting thread!

I have a question....

If (when) I purchase an HDTV when my SD breaks down, I will connect it via HDMI cable to my R22 which supplies it with a 480p SD signal. I assume this is also the resolution other DirecTV customers are viewing on their HDTVs with the HR21 (HD DVR) when watching an SD program.

Is the quality going to be the same as that SD program viewed on my (present) SD TV?

3LNB Phase III Dish * 2-R15-300 * R22-200 * D12-100 * DirecTV Subscriber since Y2K


#11 OFFLINE   Grentz

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Posted 16 January 2009 - 09:25 PM

It can be simplified even more in saying that better displays (such as newer LCDs, DLPs, Plasmas, etc.) show all the flaws in the SD signal more.

Older CRTs generally have a bit of a blur aspect to them that makes SD picture look much better. You can really see this on older CRTs that have component inputs that will even "blur" HD resolutions a bit and take down the sharpness, but better blend the pixels to improve crappier pictures. It is really just differences in display technology. New displays are not worse, quite the contrary, they are MUCH better at displaying SD content which is where the problem comes in...you can see the flaws much more.
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#12 OFFLINE   BattleZone

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Posted 16 January 2009 - 09:32 PM

Standard NTSC is 480i, not 480p. Technically, it's 720x480/60i.

Anyway, the R22 can convert this to 480p, or your TV can, but the signal is only as good as the weakest link, and in this case, it's the SD signal that DirecTV converts to 480x480/60i. And given that your new TV will almost certainly be a fixed-panel (LCD or plasma) TV that's larger than your current TV, the SD will look worse from the same viewing distance.

If, say, you had a 32" TV and went with a 37" HDTV, and were watching SDTV in pillar box (black bars on the sides and a 4:3 picture in the middle), your effective screen size would be about the same, so the rest of the difference would be the difference between analog CRT scaling and fixed-pixel digital scaling. CRTs do scaling better, or at least, more pleasing to the eye. Plasma does a bit better than LCD, but has other trade-offs.

#13 OFFLINE   Davenlr

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Posted 16 January 2009 - 09:37 PM

With the Directv HD receivers hooked via HDMI, and viewing an SD channel, the following options are available:

480i (tv upscales to its own resolution and deinterlaces)
480p (tv upscales to its own resolution)
720p (Directv receiver upscales picture)
1080i (Directv receiver upscales picture)

Which is better is dependent on the quality of the scaler in the tv itself, and if its better or worse than the one in the Directv receiver.

#14 OFFLINE   peano

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Posted 16 January 2009 - 11:58 PM

My guess is the OP is installing a lot of LCD TVs. SD looks terrible on direct view LCDs. I would say CRT RearPro would be the best, followed by plasma, then DLP then LCD Rearpro and last and definitely least LCD direct view.

#15 OFFLINE   yooper99

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Posted 17 January 2009 - 06:51 AM

You're right peano, most of the TVs are LCDs. I am using an old RCA F38310 CRT "HDTV" at home and have quite a good picture with DirecTV in SD.

Thanks one and all for the great info.

#16 OFFLINE   genemc

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Posted 17 January 2009 - 08:34 AM

In my opinion it is the scaler, whether in the TV or the Direct receiver that is the main issue. I have a Pioneer Kuro 60 inch (not the elite) hooked up to both an HR-20 and an HR-21 and the standard definition channels are very watchable. Obviously, they are not as sharp as the HD channels but they are at least on a par with my Mitsubishi 27 inch 4x3 CRT. I consider myself fairly picky about picture quality and am ISF trained and certified.

#17 OFFLINE   SatRick

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Posted 17 January 2009 - 09:00 AM

I think it may depend on the TV as well
I have a Panny 50PZ85 plzma running SD and it looks as good as my neibors 42" cheap LCD in HD

#18 OFFLINE   Artwood

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Posted 17 January 2009 - 02:28 PM

How much difference is there between 480X480 and 720X480?

If 720X480 = SD and sucks--doesn't that mean that DirecTV down-rezzing to 480X480 would mean that SD would SUCK MORE?

Is it possible that by making the SD channels suck more--that people become more forgiving of HD channels that are ADDITIONALY COMPRESSED?

#19 OFFLINE   bonscott87

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Posted 17 January 2009 - 02:52 PM

Is it possible that by making the SD channels suck more--that people become more forgiving of HD channels that are ADDITIONALY COMPRESSED?


Well, DirecTV has been at that SD resolution for 15 years so I don't think HD has anything to do about it.

Plus the fact that DirecTV offers it's HD channels in MPEG4 at *full* resolution your argument doesn't really work in this case. :)

#20 OFFLINE   Jeremy W

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Posted 17 January 2009 - 04:44 PM

Well, DirecTV has been at that SD resolution for 15 years so I don't think HD has anything to do about it.

I'm fairly sure that they didn't start down-rezzing SD until they started doing LILs.




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