A Discussion On Poor SD On HDTVs

maclarenjc · 10-07-2005, 10:33 AM

You will need to have a cable line running back into the house which has a power adapter plug on the end (supplied with amp) which goes into a normal power outlet. In my case I had an unused line going into the basement from the junction box so I just hooked up the power adapter to the end of that cable line which was already near a power outlet.

If you do not have an existing line which can be repurposed then a new entry point through the foundation/wall will have to be drilled and a new line ran.

I did see improvement even by just putting the amplifier inside the house on the line running to my main TV but the maximum benefit comes from improving all lines before the signal splits. In many cases the splitter is inside the house so its easier to attach the power supply line.

JackKarle · 10-16-2005, 08:10 AM

Great post. I will print is. I manage a store that sells big screen HDTV's, and the number of returns is very high. I don't blame people who spend 2 to 4 thousand on a 50" hdtv, take it home, and see a worse picture than they did on their $150 26" set.

InterceptPoint · 10-25-2005, 05:08 PM

I currently have DIRECTV and a fairly old 40" Mitsubishi NTSC TV and am about to spring for a 70" JVC 1080p HDTV. So I have a real interest in SD quality and what we might be able to do to improve it.

In my case, the SD signal from DIRECTV looks super on my 40" Mits so there is nothing that DIRECTV is doing compression-wise to mess up the signal. I have seen that same signal on a $6000 Mits 70" DLP and it doesn't look as good no matter how far back you stand. I would venture to say that I could make the same comment about a 40" DLP if there was one.

My point is that you cannot explain the poor SD quailty away with arguments just based on signal quality (after all, it looks good on my Mits NTSC) or size. There is something more to it than that. I'm still waiting for a good explanation of why a digitial signal (from my DIRECTV STB) fed into a digital TV doesn't look as good as one that has to go through an D/A converter before it is displayed on (for example) a 1974 TV.

We're missing something somehow. It's not the compression. It's not just the size either although that is a factor. It has to be the HDTV processing that is screwing up the picture. I just don't understand how or why.

**rbinck** · 10-25-2005, 05:36 PM

Well it is mostly the compression and decompression. On a SDTV the resolution will not be upscaled and the artifacts don't show up. Here is an example of what is typical between a HDTV and a SDTV:

The photo on the left is what is expected due to the combination of decompression and resolution enlargement of a HDTV. The photo on the right is what is to be expected from just decompression on a SDTV. A lot cleaner.

Some HDTVs process SD up to HD resolutions better than others. The TV that use the Faroudja DCDi processors or the Fujitsu processors will do the best as they anticipate the noise due to decompression and eliminate some of it.

So in a way it is the HDTV processing (or lack of it) that is screwing up the picture.

InterceptPoint · 10-25-2005, 06:14 PM

Quote:

Originally Posted by rbinck

Well it is mostly the compression and decompression. On a SDTV the resolution will not be upscaled and the artifacts don't show up. Here is an example of what is typical between a HDTV and a SDTV:

The photo on the left is what is expected due to the combination of decompression and resolution enlargement of a HDTV. The photo on the right is what is to be expected from just decompression on a SDTV. A lot cleaner.

Some HDTVs process SD up to HD resolutions better than others. The TV that use the Faroudja DCDi processors or the Fujitsu processors will do the best as they anticipate the noise due to decompression and eliminate some of it.

So in a way it is the HDTV processing (or lack of it) that is screwing up the picture.

I think you've got it right.

For the new 1080p sets, however, you would think that simple line doubling and a display of 480x2 or 960 lines in a 4:3 format would be fairly artifact free. OTOH, there is the issue of deinterlacing. The HDTV has to deinterlace to generate the progressive scan so that is another area where the processing can be less than optimum. Nevertheless that process is pretty darn good for 1080i to 1080p so I still don't get it.

**rbinck** · 10-25-2005, 06:50 PM

Now deinterlacing 1080i to a 1080p set is a one to one issue. There is no scaling involved. To deinterlace they take each field and build up the frame in a video memory then display out of that memory at the 60fps. I've not seen any SD video on any of the 1080p TVs yet, but I'm sure it will depend on the source. My guess is the cable and satellite will look really bad, the analog bad and the SD upconverted by the broadcast stations (OTA) will look pretty good, just like it is on my TVs.

Luddite · 12-01-2005, 02:48 PM

I have been having problems with certain cable
tv channels. I do think it is because of over
compression. Bright vivid parts of movies look
great, then when cloudy, sunfilter lighting,
smoke, or any atmospherics that cause mono-
coloring of the picture comes up, I can see
blocks instead of a smooth picture. Sometimes
the picture takes on a poster look (posterization,
maybe?). It happens on the new 42 in. Samsung
rptv and the old small Sanyo circa 1980. How can
I tell if the compressiom problem is the cable
company's fault or from the source of channels
(SciFi, Cinemax, Lifetime, etc.)? Sorry if posted
in wrong forum.

**rbinck** · 12-01-2005, 03:51 PM

This is a fine place to ask that question. Here is what I tell customers. If it was your TV's fault, then the problem would exist when you are watching DVDs. A good progressive scan DVD player with a good video processor will give you just about the best SD picture you can get. Generally this will be at the EDTV level. Next the SD on your local OTA digital stations where they have upconverted their SD using very expensive video processors should be just about as good. Next down the PQ level would be the local digital stations you get over your cable, although in this area it is very close to OTA. Now when you are watching satellite or cable SD channels, you hit the worse PQ with channels varying from fairly good to very poor. On my Directv some of the channels are worse that watching a VHS tape. And yes, those channels you mentioned are highly compressed and particularly bad PQ. I watch them on a SDTV.

Luddite · 12-02-2005, 02:02 PM

Quote:

Originally Posted by rbinck

This is a fine place to ask that question. Here is what I tell customers. If it was your TV's fault, then the problem would exist when you are watching DVDs. A good progressive scan DVD player with a good video processor will give you just about the best SD picture you can get. Generally this will be at the EDTV level. Next the SD on your local OTA digital stations where they have upconverted their SD using very expensive video processors should be just about as good. Next down the PQ level would be the local digital stations you get over your cable, although in this area it is very close to OTA. Now when you are watching satellite or cable SD channels, you hit the worse PQ with channels varying from fairly good to very poor. On my Directv some of the channels are worse that watching a VHS tape. And yes, those channels you mentioned are highly compressed and particularly bad PQ. I watch them on a SDTV.

Thank you for answering my question. Yes, bad VHS is a perfect description of how parts of the movies and shows look. Can you explain why it is more
noticable on less vivid parts of the movies and shows? Is there any way to make it better because I am stuck with my rptv HDTV for at least another year? The Sanyo is too tiny. I have Adelphia (bankrupt and sold) digital cable.

**rbinck** · 12-02-2005, 03:04 PM

Quote:

Can you explain why it is more noticable on less vivid parts of the movies and shows? Is there any way to make it better because I am stuck with my rptv HDTV for at least another year?

Garbage in, garbage out. The cable company probably got a sub-par feed. I noticed those channels look bad on cable and both satellites. They looked bad on Voom when it was up. Not really anything you can do except gravitate to other programming.

random person · 12-03-2005, 09:43 PM

Incredibly helpful discussion. Thank you all so much!

One esoteric question: I'm getting my Panny 37 incher on tuesday and my dealer tells me that component video connections would be best with Comcast DVI/HD/DVR box. Their argument is that the DVI to HDMI connection is literally tenuous, as the connection is loose and frequently needs to be reconnected. More critically, they argue that while the component video connection degrades the HDTV signal by 10-15% it actually improves the SD signal by a comparable amount. Something to do with the digital conversion problem that degrades the SD signal with DVI/HDMI but is less of an issue with component video as it is not digital. Or something.

So, my question is this: would using a component video connection appropriately compensate for SD PQ issues? Or would you still recommend a separate S video connection for SD? Also, is my dealer insane?

Many thanks for your help!

dondada73 · 12-05-2005, 08:03 PM

I've got to say this has been one of the most informative threads i've read...for anything...in a while. many questions answered. for the record I'm dealing with a brand new Sharp Aquos LC32D4U with a Pioneer Voyager HDTV box and Samsung HD950 DVD player. Like just about everyone else here I have trouble with SD broadcasts. Picture quality is pretty bad, blurry, pixelated just like all the others here. I've read a lot of great info here and i guess what it looks like i need to look into is splitting the cable from the box to the NTSC antenna (I'd have to split again because it's already split to the box and cable modem) and/or install an amplifier. HD channels look pretty good and some actually better than others. While watching football this past weekend i noticed the CBS broadcast looked slightly better than ABC's. In any case I've got Time Warner cable coming here in a week or so to take a look, but i have a feeling i'll get better answers out of you guys here..

**rbinck** · 12-05-2005, 08:29 PM

random person, no he's not insane, but it is hard to predict success on any given connection. I've found it best to experiment with each new combination of equipment. Nothing wrong with hooking up all of the available choices. Worse that could happen is you will need to get some Y cables to patch up all of the audio connections. That way you can switch about and compare.

random person · 12-05-2005, 09:50 PM

Quote:

Originally Posted by rbinck

random person, no he's not insane, but it is hard to predict success on any given connection. I've found it best to experiment with each new combination of equipment. Nothing wrong with hooking up all of the available choices. Worse that could happen is you will need to get some Y cables to patch up all of the audio connections. That way you can switch about and compare.

Thanks again, rbinck! I was kind of leaning in the same direction -- that is, let the installers do the component video link and at the same time add an s-video connection as a separate input for SD just so I could A/B the results.

One more question for you -- by "Y cables" do you mean the audio cables? I take it that you have to run separate audio cables for each input, right? I've got tons of composite cables lying about -- can they serve as spare audio cables (obviously leaving the video cable unconnected) in a pinch?

Thanks so much for your help!

**rbinck** · 12-06-2005, 12:25 PM

Yes the Y cables are for the audio because you may only have one audio output and you do need to run separate cables for each input. Component cables are fine for audio. Audio cable are normally 50 ohm coax, whereas component cables should be 75 ohm coax, although I've seen some that look mopre like 50 ohm construction. Either will work for audio just fine.

10-07-2005, 10:33 AM	#46
maclarenjc What is HD? Join Date: Sep 2005 Posts: 3	Power supply hookup You will need to have a cable line running back into the house which has a power adapter plug on the end (supplied with amp) which goes into a normal power outlet. In my case I had an unused line going into the basement from the junction box so I just hooked up the power adapter to the end of that cable line which was already near a power outlet. If you do not have an existing line which can be repurposed then a new entry point through the foundation/wall will have to be drilled and a new line ran. I did see improvement even by just putting the amplifier inside the house on the line running to my main TV but the maximum benefit comes from improving all lines before the signal splits. In many cases the splitter is inside the house so its easier to attach the power supply line.

10-16-2005, 08:10 AM	#47
JackKarle Jack Karle Join Date: Aug 2005 Location: DeBary, Florida Age: 60 Posts: 2	Great post. I will print is. I manage a store that sells big screen HDTV's, and the number of returns is very high. I don't blame people who spend 2 to 4 thousand on a 50" hdtv, take it home, and see a worse picture than they did on their $150 26" set. __________________ Jack Karle

10-25-2005, 05:36 PM	#49
rbinck Super Moderator Join Date: Apr 2004 Location: Houston, Texas Posts: 10,612	Well it is mostly the compression and decompression. On a SDTV the resolution will not be upscaled and the artifacts don't show up. Here is an example of what is typical between a HDTV and a SDTV: The photo on the left is what is expected due to the combination of decompression and resolution enlargement of a HDTV. The photo on the right is what is to be expected from just decompression on a SDTV. A lot cleaner. Some HDTVs process SD up to HD resolutions better than others. The TV that use the Faroudja DCDi processors or the Fujitsu processors will do the best as they anticipate the noise due to decompression and eliminate some of it. So in a way it is the HDTV processing (or lack of it) that is screwing up the picture. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

10-25-2005, 06:50 PM	#51
rbinck Super Moderator Join Date: Apr 2004 Location: Houston, Texas Posts: 10,612	Now deinterlacing 1080i to a 1080p set is a one to one issue. There is no scaling involved. To deinterlace they take each field and build up the frame in a video memory then display out of that memory at the 60fps. I've not seen any SD video on any of the 1080p TVs yet, but I'm sure it will depend on the source. My guess is the cable and satellite will look really bad, the analog bad and the SD upconverted by the broadcast stations (OTA) will look pretty good, just like it is on my TVs. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com Last edited by rbinck; 12-05-2005 at 08:30 PM.

12-01-2005, 02:48 PM	#52
Luddite How can anyone watch standard def? Join Date: Nov 2005 Posts: 15	Compression problems? I have been having problems with certain cable tv channels. I do think it is because of over compression. Bright vivid parts of movies look great, then when cloudy, sunfilter lighting, smoke, or any atmospherics that cause mono- coloring of the picture comes up, I can see blocks instead of a smooth picture. Sometimes the picture takes on a poster look (posterization, maybe?). It happens on the new 42 in. Samsung rptv and the old small Sanyo circa 1980. How can I tell if the compressiom problem is the cable company's fault or from the source of channels (SciFi, Cinemax, Lifetime, etc.)? Sorry if posted in wrong forum.

10-25-2005, 05:08 PM	#48
InterceptPoint What is HD? Join Date: Oct 2005 Posts: 2	I currently have DIRECTV and a fairly old 40" Mitsubishi NTSC TV and am about to spring for a 70" JVC 1080p HDTV. So I have a real interest in SD quality and what we might be able to do to improve it. In my case, the SD signal from DIRECTV looks super on my 40" Mits so there is nothing that DIRECTV is doing compression-wise to mess up the signal. I have seen that same signal on a $6000 Mits 70" DLP and it doesn't look as good no matter how far back you stand. I would venture to say that I could make the same comment about a 40" DLP if there was one. My point is that you cannot explain the poor SD quailty away with arguments just based on signal quality (after all, it looks good on my Mits NTSC) or size. There is something more to it than that. I'm still waiting for a good explanation of why a digitial signal (from my DIRECTV STB) fed into a digital TV doesn't look as good as one that has to go through an D/A converter before it is displayed on (for example) a 1974 TV. We're missing something somehow. It's not the compression. It's not just the size either although that is a factor. It has to be the HDTV processing that is screwing up the picture. I just don't understand how or why.

12-01-2005, 03:51 PM	#53
rbinck Super Moderator Join Date: Apr 2004 Location: Houston, Texas Posts: 10,612	This is a fine place to ask that question. Here is what I tell customers. If it was your TV's fault, then the problem would exist when you are watching DVDs. A good progressive scan DVD player with a good video processor will give you just about the best SD picture you can get. Generally this will be at the EDTV level. Next the SD on your local OTA digital stations where they have upconverted their SD using very expensive video processors should be just about as good. Next down the PQ level would be the local digital stations you get over your cable, although in this area it is very close to OTA. Now when you are watching satellite or cable SD channels, you hit the worse PQ with channels varying from fairly good to very poor. On my Directv some of the channels are worse that watching a VHS tape. And yes, those channels you mentioned are highly compressed and particularly bad PQ. I watch them on a SDTV. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com Last edited by rbinck; 12-01-2005 at 03:53 PM.

12-03-2005, 09:43 PM	#56
random person How can anyone watch standard def? Join Date: Nov 2005 Posts: 20	Incredibly helpful discussion. Thank you all so much! One esoteric question: I'm getting my Panny 37 incher on tuesday and my dealer tells me that component video connections would be best with Comcast DVI/HD/DVR box. Their argument is that the DVI to HDMI connection is literally tenuous, as the connection is loose and frequently needs to be reconnected. More critically, they argue that while the component video connection degrades the HDTV signal by 10-15% it actually improves the SD signal by a comparable amount. Something to do with the digital conversion problem that degrades the SD signal with DVI/HDMI but is less of an issue with component video as it is not digital. Or something. So, my question is this: would using a component video connection appropriately compensate for SD PQ issues? Or would you still recommend a separate S video connection for SD? Also, is my dealer insane? Many thanks for your help!

12-05-2005, 08:03 PM	#57
dondada73 eye candy Join Date: Dec 2005 Location: nyc Age: 35 Posts: 60	good stuff I've got to say this has been one of the most informative threads i've read...for anything...in a while. many questions answered. for the record I'm dealing with a brand new Sharp Aquos LC32D4U with a Pioneer Voyager HDTV box and Samsung HD950 DVD player. Like just about everyone else here I have trouble with SD broadcasts. Picture quality is pretty bad, blurry, pixelated just like all the others here. I've read a lot of great info here and i guess what it looks like i need to look into is splitting the cable from the box to the NTSC antenna (I'd have to split again because it's already split to the box and cable modem) and/or install an amplifier. HD channels look pretty good and some actually better than others. While watching football this past weekend i noticed the CBS broadcast looked slightly better than ABC's. In any case I've got Time Warner cable coming here in a week or so to take a look, but i have a feeling i'll get better answers out of you guys here..

12-05-2005, 08:29 PM	#58
rbinck Super Moderator Join Date: Apr 2004 Location: Houston, Texas Posts: 10,612	random person, no he's not insane, but it is hard to predict success on any given connection. I've found it best to experiment with each new combination of equipment. Nothing wrong with hooking up all of the available choices. Worse that could happen is you will need to get some Y cables to patch up all of the audio connections. That way you can switch about and compare. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com

12-06-2005, 12:25 PM	#60
rbinck Super Moderator Join Date: Apr 2004 Location: Houston, Texas Posts: 10,612	Yes the Y cables are for the audio because you may only have one audio output and you do need to run separate cables for each input. Component cables are fine for audio. Audio cable are normally 50 ohm coax, whereas component cables should be 75 ohm coax, although I've seen some that look mopre like 50 ohm construction. Either will work for audio just fine. __________________ www.highdefinitionblog.com www.BlogOfHawaii.com Last edited by rbinck; 12-06-2005 at 12:28 PM.

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