[LazySoAndSo]

Why are the SD images for so many televisions so poor?

I spent ages getting around to getting a new TV, and one thing that put me off was the really poor SD images on many of them. As I have DVDs and most channels are still SD, most of my watching will be SD for some while.

I've now got a TV (Sony 32EX723) which seems to have a good SD image. OK, 32" is not exactly the most challenging TV for SD, but even so, I saw many poor SD images on 32" sets.

Surely it's not rocket science to upscale SD images....

[Psycho Sonny]

you need a HD set top box, that will upscale SD to HD, it wont be as clear as HD but still a lot better than SD.

you also need an upscaling dvd player which have been available for many years now.

[andy1249]

Always makes me laugh that rocket science crack.
A simple payload,a tube full of fuel, a trajectory to work out via some simple secondary school math , and your good to go.
Rockets can be, and often are, built and launched by children.

Scaling chipsets on the other hand are very complicated VLSI semiconductor chipsets with transistor counts in the billions that are fabricated in plants that cost billions and are one of the most complicated entities ever built by man.

Designs are jealously guarded and all still very much protected by patent. Only the major manufacturers have decent scaling chipsets and they don't share.

Add to that the fact that most sell players of some kind as well and they keep the better performing chipsets for these as opposed to their screens , and you can see why SD performance varies so much.

[LazySoAndSo]

Originally Posted by andy1249

Always makes me laugh that rocket science crack.
A simple payload,a tube full of fuel, a trajectory to work out via some simple secondary school math , and your good to go.
Rockets can be, and often are, built and launched by children.

Scaling chipsets on the other hand are very complicated VLSI semiconductor chipsets with transistor counts in the billions that are fabricated in plants that cost billions and are one of the most complicated entities ever built by man.

Designs are jealously guarded and all still very much protected by patent. Only the major manufacturers have decent scaling chipsets and they don't share.

Scalling images from one resolution to another is a well understood problem, and there is a whole lot of open source software such as The GIMP which does so does not, as far as I'm aware, use any particular patent encumbered methods to do so. The open source video processing and transcoding software mplayer (and ffmpeg and others) can resample movies to higher resolution, and they don't look bad.

But SD pictures on some televisions look awful. Why? It's not that it is too difficult a problem that requires patented technology.

Add to that the fact that most sell players of some kind as well and they keep the better performing chipsets for these as opposed to their screens , and you can see why SD performance varies so much.

That's a reasonable suggestion which might be the reason. Cripple the sets and try and sell them extra upscaling kit.

[andy1249]

Scalling images from one resolution to another is a well understood problem, and there is a whole lot of open source software such as The GIMP which does so does not, as far as I'm aware, use any particular patent encumbered methods to do so. The open source video processing and transcoding software mplayer (and ffmpeg and others) can resample movies to higher resolution, and they don't look bad.

TV's are not general purpose computers , running such software is beyond most if not all of them. In any case , hardware solutions are always better , and proprietary hardware solutions is the way most dedicated display devices choose to go.

I have an HTPC myself , and have used ffdshow for upscaling in many of its iterations , and it has never ever performed as good as a dedicated chipset.

If fact one of the things that stopped me spending so much time trying to get the HTPC as good as dedicated chipsets , is how consistently and comprehensively its upscaling quality is beaten by cheap as chips hardware like the sumvision cyclone , the WDTV live , the Dune , and the many many other players available.

[LazySoAndSo]

Originally Posted by andy1249

TV's are not general purpose computers , running such software is beyond most if not all of them. In any case , hardware solutions are always better , and proprietary hardware solutions is the way most dedicated display devices choose to go.

No, they won't be able to run the software. But they will be able to apply
the techniques used in the software I mentioned.

As an example, Interpolation using a table of filter coefficients depending on the location of the virtual pixel should produce a very decent result, and be ultra-trivial to implement in hardware. There may be some colour smudging effects, but it shouldn't be as bad as the horrible glitching that I've seen on some sets.

I have an HTPC myself , and have used ffdshow for upscaling in many of its iterations , and it has never ever performed as good as a dedicated chipset.

Given how poor some of the SD pictures are on TVs I've seen, if ffdshow (which I haven't used) is worse, then I think that says something about the software rather than anything else.

[andy1249]

No, they won't be able to run the software. But they will be able to apply
the techniques used in the software I mentioned.

As an example, Interpolation using a table of filter coefficients depending on the location of the virtual pixel should produce a very decent result, and be ultra-trivial to implement in hardware. There may be some colour smudging effects, but it shouldn't be as bad as the horrible glitching that I've seen on some sets.

Actually no they couldnt , for legal reasons.
One of the main differentiators that manufacturers have is how they handle non native resolution content , most choose proprietary chipsets to do this , if they were to use open software or open software techniques , then they would , under the terms of the GPL , have to share that information with anyone in the open source community.

Thats not going to happen , most would say they have a hard enough time selling sets as it is without sharing the few tricks they have left.

The only unit that does use software based techniques for upscaling ( software is not open by the way ) is the PS3.
That unit is sold at a loss , the idea being that the money is recouped through software titles , which are expensive in anyones book.

If that unit were sold with the same model as other AV gear , it would be well in excess of 1000 pounds.

You are underestimating the kind of processing power needed to run software based scaling models , if you added that to a standard TV the price would be too high for most of the general public.

Thats why proprietary scaling chipsets are the norm , and its likely to stay that way , hardware based SoC's are much much cheaper to add to displays than processor muscle and software routines.

[LazySoAndSo]

Originally Posted by andy1249

Actually no they couldnt , for legal reasons.
One of the main differentiators that manufacturers have is how they handle non native resolution content , most choose proprietary chipsets to do this , if they were to use open software or open software techniques , then they would , under the terms of the GPL , have to share that information with anyone in the open source community.

Resampling of images using tables of filter coefficients is in the public domain, and has been for a long time. So, legally, as well as practically, they could.

It's a very easy technique and was invented a long time ago.

The only unit that does use software based techniques for upscaling ( software is not open by the way ) is the PS3.
That unit is sold at a loss , the idea being that the money is recouped through software titles , which are expensive in anyones book.

I think you're misunderstanding what I write. I'm not saying that the manufacturers could use the code from OS projects, I'm saying that they can use the techniques. The techniques in OS software are typically in the public domain, and hence can be used without any GPL or other restrictions. Remember that the whole point of the patent system is that discoveries are protected for a short time (e.g. 25 years) so that the inventor can profit from them, and then released into the public domain. I am talking of techniques that are MUCH older than 25 years old.

You are underestimating the kind of processing power needed to run software based scaling models , if you added that to a standard TV the price would be too high for most of the general public.

No, I'm not. I'm discussing the kind of hardware sophistication you'd need to do image size upscaling in hardware, and there are some techniques that will give good (if not state of the art, but I am comparing to TVs with horrible pictures) results and be trivial to implement in hardware. Just because a technique is used by, e.g., The GIMP, does not mean that you have to run The GIMP inside a television to run them. Any competent engineer can use the same techniques, e.g. by referring to basic textbooks in image processing, in hardware.

Thats why proprietary scaling chipsets are the norm , and its likely to stay that way , hardware based SoC's are much much cheaper to add to displays than processor muscle and software routines.

Yes, and it's also easy and cheap to implement decent quality image scaling methods in these chipsets that will give much better results than some of the awful upscaling I've seen on TVs. So, why don't they? I think there might be some truth in your suggestion of manufacturers deliberately not making cheaper TVs too good or people won't buy the more expensive ones. But in terms of hardware costs, it isn't necessary to have SD images that bad on cheap TVs.

[Boostrail]

Despite the technical/processsing/cost arguments above I cannot understand why the IDTV upscaling from many blue chip manufactureres is so poor when the upscaling by external boxes that deliver 1080i or even 1080p from 576i inputs is so much better?

[martinthorn1]

Why are the SD images for so many televisions so poor?

Sometimes it's because the TV has various noise reduction and motion 'improvement' features turned on which are not required. Turn these off unless doing so makes things worse. Sometimes it's because the sharpness is set too high: this is characterised by excessive 'ringing': highlights around high contrast edges and the default setting (halfway) tends to be too high on most TVs.

Big TVs also exaggerate the undesired features of bandwidth throttled SD digital tv signals : scenes with lots of detail and motion really struggle in SD such as football: the grass often turns into pixellated green blocks. It's a sad fact that in order to cram in loads of rubbish channels, SD channel bit rates are lower than ideal for a good picture at times..(HD channel bit rates are a bit stingey as well). Some TVs hide these SD signal source problems better than others.. (better MPEG noise reduction)

Sometimes the TV just has a poor scaling algorithm as already discussed by others below..

Rockets can be, and often are, built and launched by children.

Children can also resize images in paintshop pro.. in other words you can't compare the design of ion thrusters or the CFD done in rocket nozzle design for example to the rockets kids build.

Scaling chipsets on the other hand are very complicated VLSI semiconductor chipsets with transistor counts in the billions

Transistor counts aren't necessarily a sign of complication (eg. RAM) but yes I'm sure there are some clever algorithms hardwired into some of these asics (and some not so clever )

[satengineer]

SD on 768 Panny plasmas looks fantastic!! As does 1080i broadcast TV.

The mistake everyone makes is buying 1080 screens!!

[diablo]

Originally Posted by satengineer

SD on 768 Panny plasmas looks fantastic!! As does 1080i broadcast TV.

The mistake everyone makes is buying 1080 screens!!

I don't think they still do 32" plasma screens, otherwise I might have bought one for my front room.

My new Panasonic LT32ET5B does a reasonable job on SD, though my Samsung 1080p projector on a 90" screen seems to do better - even when fed from the same sources.

p.s. the 32" SD tends to look better when viewed in 'game' mode.