I've just purchased my first HD TV from ebuyer.

Hannspree XV JT01-32E2-000 for £299.... great reviews, so I went for it.

Now the only HD source I have is a XBOX360 which i'll hook up using the VGA cable i'm using at the moment on my pc monitor. Can't afford SKY HD so my only options are:

A freeview or DVD player which upscales the picture to HD.

Now my question is.... do they really work and whats the picture quality like.

It depends how well your TV upscales SD pictures. If it does a good job then there will be no improvement, the picture may well be worse. If your TV does a poor job then an upscaling DVD player may produce an improved picture.

The only way to know for sure whether your picture will improve or get worse with an upscaled source is to actually try it.

Whatever you buy it won't be HD unless you get Sky+, one of the high definition DVD players or another genuine HD source rather than an upscaler.

Spot the deliberate mistake!

Should (obviously) read "unless you get Sky HD".

But as suggested, an upscaler doesn't do anything your TV doesn't already, and it doesn't make your SD pictures HD.

However, on the plus side - cheap sets usually have awful upscalers, so an external one could make an improvement for you?. But get out of your mind than ANY of these devices actually upscale to HD, because they don't (and can't).

But of course there are specialist image scalers/processors around which DO turn SD signals to HD and beyond. Expect to pay £2k+ though, which only makes them suitable for expensive home cinema installations. Only useful if the end display can accept its native resolution without doing any scaling itself.

{before Nigel argues with me, I should know - I design them! see some of my products here, www.calibreuk.com, from £2k for home theatre use to £45k for professional digital cinema processors}


LCDMAN............The man with no sig
Last edited by LCDMAN : 21-10-2007 at 18:13

You certainly do get more performance from the high end kit but at the end of the day upscaled SD is and will forever be just that
Of course when you spend serious money on AV a couple of grand to optimise SD sources is a no-brainer, at those price points a minor improvement is worth paying for even when native HD source material is available.

Since you design them you know they aren't HD just upscaled SD. These products and others like them do an excellent job and will improve almost any TV (as long as like you say there isn't further scaling in the TV) but the output is still SD.

An HDMI source should still be better than one through a SCART though, as you have don't have the deleterious DA-AD conversion -- the AD part of which re-compresses the image that was previously uncompressed by the decoder directly behind the DA converter. You also don't have to deal with the frankly rubbish SCART standard, with all the crosstalk etc problems associated with that.

Hence an HDMI connection should ALWAYS be better than an analogue connection.

The picture should therefore never be *worse*, because worst-case scenario you just set the HDMI connection to output in the source's native resolution.

Doesn't your Xbox 360 already upscale DVDs? Your cheapest route to real HD movies would be to buy the HD-DVD drive for the 360.

It does not re-compress the image, the image going down either HDMI or SCART is not compressed. There is some loss of quality in doing the extra D/A-A/D conversion but this in many cases may not have much affect, though as you say it's usually better to stay digital if you can - it's unlikely to be worse unless something strange is going on.

I was under the impression that many televisions *do* recompress analogue images as they come in to store in buffers. Is this duff information?

That's duff information. The reason that images are compressed is to send them over mediums (such as radio or satellite comms) or stored on items such as DVDs (DVDs would be impossible without compression).

However images sent across links such as HDMI or SCART are sent decompressed, digital decompressed has a much higher bandwidth than analogue, HDMI is designed to allow this higher bandwidth.

It's important to realise why images are compressed, this is purely to reduce the amount of storage used or the amount of bandwidth needed to send them. To process the image it's necessary to de-compress the image - as far as I know it's impossible to process a compressed image without decompressing it first.

The only TVs that would recompress an image would be those few that are also PVRs (Humax and LG), they will compress the input image (HDMI or SCART) to fit efficiently on the HDD.

Ok, since you're obviously the expert here, perhaps you can explain how taking 576i/50Hz SD signals, sampling them at massive multiples of the subcarrier frequency in 4:4:4 YUV, before giving that to a sophsticated scaling engine running at over 1TFlop and using Teranex algorithms to interpolate spatially and temporaly whilst eliminating block noise artefacts, mosquito noise and MPEG encoding noise before spitting out at least 1920 x 1080 pixels @60Hz doesn't make it HD? All using a 12 bit data path to ensure a true 10 bit output, of course.

I am referring to a dedicated stand alone image processor/scaler here, not the $20 crappy chip found in most "upscaling" DVD players - which does not give out HD.


LCDMAN........The man with no sig!

It doesn't matter how much the processor/scaler costs, or how sophisticated it is, the resolution you have started with is SD (576i), basically all the upscaler is doing is guessing and filling in the missing information that would be there on a HD resolution image. The image will be of a HD resolution that's all, it will not be true HD, true HD material has to be captured at 720/1080i/1080p. Movies will be filmed at even higher resolutions, these are then downscaled for home viewing.

You only have to look at Sky One HD when it not broadcasting a HD programme, the image will have been upscaled prior to broadcasting by very sophisticated equipment (H.264 encoders I believe), it does a good job and there's a noticeable difference to the broadcast image on it's SD channel (106), but you can see it's not HD.

Nothing to do with upscaling! All encoding does is introduce even more crap & noise in to the image by making compromises. All the sort of stuff we have to take out to make a half decent image again. Yes, we can correct for all encoding noise, even when the encoding algorithm was not applied accurately and consistently. We also correct telecine cadence defects (3:2, 2:2, and non-standard and broken cadences) that make your pictures jump & twitter when originated from film material.


A sophisticated scaler doesn't "guess" what the "missing" pixels should be, it creates them accurately using spatial (place) and temporal (time) interpolation algorithms.


An unsophisticated scaler (like the $20 chip in most cheapo "upscaling" DVD players) DOES guess, hence the s**t result. This is not HD.


LCDMAN...................The man with no sig!

All I know is that Sky use H.264 (MPEG 4) for transmission purposes, so assume it would be this equipment that would be doing the upscaling.


If the information is not there then I would have to say there is an element of guess work.


And it is still won't be HD when you scale the image from a high end scaler, a better image yes (in most cases) but it's not HD

Never assume - it makes an ASS of U and ME Encoding is not upscaling. As I said earlier, encoding as a process only serves to degrade the image further because it does have to make compromises - however small.


The "information" provided is used to make new "information", that's the whole principle of interpolation. It's not guess work because it is accurately repeatable.


We obviously move in very different technological circles, so to speak. You can make a HD signal out of an SD signal, {it isn't easy or cheap to do so isn't going to be in cheap DVD players or SKY-HD boxes} you just don't believe it and there we will have to agree to differ.


LCDMAN..................The man with no sig!
Last edited by LCDMAN : 22-10-2007 at 11:18

I don't see as being repeatable means it isn't guesswork?, it's trying to create something which doesn't exist, so obviously has to 'guess' what might be there. Just as you yourself would make a guess, it does so based on the surroundings - so it's a potentially educated guess, but still a guess, and may bear no resemblance to what should be there.


Sorry, I don't beleive it either - at least not to any degree of accuracy - and presumably broadcasters would have access to the degree of technology required?, yet they don't appear to use it?.

OK, I'm lying, it's really all smoke and mirrors!

But seriously, broadcasters don't turn all their SD stuff to HD before broadcast as they are just going to encode/compress it anyway, squeeze it as much as possible and make it look crap again!


The information may have existed previously (take a movie turned to 576i, lots of information "lost" by down scaling that can be accurately recovered using the right algorithms) and can be recreated - that isn't guesswork. Most processes that a signal undergoes can be accurately and repeatably reversed if it is known what the process was, even if it was applied inconsistently or unevenly.

The OP was asking if he could get HD via an upscaling DVD player - no he can't but there are ways to make HD from SD, honest! Whether there is any benefit to doing this in any particular application depends on many other factors.


Adios,



LCDMAN.................The man with no sig!

would call it an educated guess.

Obviously the information isn't there so it's having to make it up based on something, in instances like this it would be based on advanced analysis of the information there is and what that image looks like in order to determine what an HD version would be. Chances are it won't be as good as a "true" HD image but it's going to be a hell of a lot better than something that effectively just doubles each pixel or just zooms the image to get an "HD" version. And if based on a high quality SD version could be a lot better than a heavily compressed HD version.

As has been mentioned, it's not the sort of thing you get in Comet otherwise everyone would have one and they wouldn't bother transmitting or even filming in HD.

Actually they do, try recording an SD programme on Sky One and the same programme on Sky One HD, the HD version is upscaled before broadcast and takes a great deal more disk space, as much as an HD programme.

But it still looks nothing like an HD programme, although it is slightly better than the SD version - but this may be as much to do with the higher transmission path bandwidth as the professional upscaling?.

I can't help thinking that if they used the HD bandwidth for the SD programmes, SD would look pretty damn good anyway?.

That was the reasoning behind Superbit DVD, less compression should provide a better picture, of course many also believed it was pure marketing and original DVD releases were reduced in PQ even when their was plenty of disk space left

As we know from the range of SD channels now the bandwidth used (and resolution) directly reflects the final picture quality. Increasing the bitrate of SD channels would make them far more viable for larger flat panels and rock solid on CRT's but as we know economics plays a part.

At the end of the day SD is SD and regardless of the scaling (cheap DVD upscaler, decent TV scaler, Iscan/Crystalio Scaler or broadcast standard) which would raise the resolution to what is regarded as HD and everything else being equal a native HD production and broadcast should eclipse it in everyway.

Unfortunately it is the broadcast bit that invariably screws things up as that is where compromises are made! A native HD production sent over a medium with no processing/compression required to do so and addressing a display capable of an exact pixel for pixel match to the original resolution is very good though.


LCDMAN.............The man with no sig!

Well scalers do it so why can't I.


What information, if it hasn't been captured through high resolution then to me it would be guess work to make up the completed image. Repeated? The resolution that makes up HD is not repeated. Just goes to show how different the two formats are, at the end of the day - upscaled SD is still SD regardless of what processing/scaling you apply.

You can upscale the SD resolution to a HD resolution, but it will never be HD. The only major difference(s) between the cheaper upscaling DVD players and high end scalers is the price and the quality of the scaling, high end scalers do a better job.

So it does guess then!

"Interpolation" = "guesswork", by definition.

It can be a very good guess, but it is a guess nonetheless.

From the dictionary:


One system will take a group of neighbouring pixels over a group of neighbouring frames and make a damn good estimate of what light level to place a given extra pixel at, the other will simply take an x*x grid and create a weighted average of the neighbouring pixels (worst-case scenario).

But neither of them is inventing new information out of nowhere -- it is still an estimate.

It is a pretty good bet that the systems Sky are using for their upscaling equal the quality of the systems you develop -- but their upscaled images, while very good, still ain't HD.

Indeed there is no reason why the algorithm couldn't be implemented in software (non-realtime) -- but again it isn't revolutionising old footage is it?

I didn't say encoding was upscaling, I said the upscaling was probably done via the H.264 encoders.

Anyway.....

Just found this H.264 encoder, I could be wrong, but it does look like it has the ability to downscale/upscale.

http://edbox.de/wDeutsch/pdf/edbox_folder_280807.pdf

Maybe my assumption was correct.