I have recently purchased a LG 81cm LCD TV with integrated HD Tuner (model 32LX2D). This TV has 1366 x 768 pixels.

I have been swapping between the parallel SD and HD broadcasts (being careful to note the 1080i vs 576p notice in the info section) and while the picture looks excellent, I am yet to see a difference in clarity between a parallel SD and HD broadcasts. Yes I have been looking at the schedule to verify when the HD broadcasts are on.

Now I know my TV does work in HD as I saw the HD demo loop on CH9 I think (lots of outdoor scenes), it was obviously HD and quite stunningly clear and detailed.

So are many the HD transmissions not really all that HD (the stations are cheating?) or am I an visual luddite?

Regards Scott

Here's a link to the TV - http://au.lge.com/md/product/prodcategoryl...ctId=1100000798

being careful to note the 1080i vs 512p?

or

576??

576p, I was writing from memory

Im in tassie where the HD content is fairly crappy compared to the mainland but, the bit rate from TDTSD is normally around 6MBits compared to the upscaled TDTHD which is around 11-12MBits.
The difference is very clear when viewed on my SanyoZ3 PJ and even on my 19" LCD PC screen.
I only fire up the PJ for TV viewing when something is telecast HD.

The difference between SD and "real "HD is obvious on both my 20" LCD and 52" LG RPTV.

Yes I also have see a definite HD broadcast, the Ch9 HD demo loop. I am yet however to see an obvious difference between the parallel HD and SD broadcasts. I was windering if others had the same experience and if there are various grades of HD? Like with MPEG encoding you can choose the bit-rate for a given resolution?

regards Scott

We only get a few shows in 1080i. I certainly noticed the difference during the darker scenes in Threshold. The detail on the walls just wasn't there in the SD picture.

The difference between SD and 'True' HD should be distinct. But not much of 'True' HD is transmitted in oz at the moment.

In my opinion it is a waste of money to spend on HD tuners at the moment.

Don't you mean low end high definition plasma's?

Hey Caligula

I couldn't agree more! I have two 42'' plasmas - one is a SD NEC which the kid's use and the other is a HD pioneer. I have had them side-by-side and I swear I prefer the SD NEC with the majority of broadcast material. Its only when tru HD is available that the pioneer shines... and then its chalk & cheese....If the NEC wasn't so darn ugly I'd swap them around because for my eyes I think it does SD better.

Markus

Plasmas is not the best display for comparing HD, & SD. To do HD justice, first make sure the source is real HD, then use a high quality projector ( the electron gun type), & blow the image up. As it is now the electron gun still rule.
Those who have privilaged to see the Sony super fine pitch CRT TV would've also see the differences.

Dogfish,
At what distance do you view your LG 81cm??

At 3 meters plus you, really cant expect to see any resolution difference, although the better colour resolution of HD over normal PAL SD should still be noticeable.

The LG is almost certainly using bob deinterlacing for 1080i content, which will limit vertical resolution to only 540 compared to SD 576.
However the horizontal resolution of 1080i will still be 1366 on the LG, which is still way better then 720 Max for SD 576i or 576p, and should result in a much clearer picture at a close viewing distance (2 meters or less).

Most of what is transmitted as SD is very poor quality, and no where near what is possible with 576i, even new Australian produced content.
A good example was the 7 network coverage of the tennis recently, man what an ugly picture.
The edge enhancement, crushed resolution and compression artefacts combined to produce a very poor quality image on a good HD display.
I have seen better quality on Foxtel-Austar, and that’s no compliment.

The strange thing is that I have seen the tennis on a mates 42” NEC SD plasma with an Ausid STB, and found the picture quite good.
The same defects where there, but the result was fare more pleasing to the eye then on my much bigger HD, display running from my HTPC.
On good 1080i, or even good SD/DVD content , the NEC plasma just does not compare to my 1080i display, and the blacks on the plasma are simply dismal.
High quality HD displays show no mercy to poor video content.

Long live three eyed monsters

Did you get Edge Enhancement on yours? Do you get PRiME or Seven in your area?

I could see EE on PRiME, but saw no trace of it on Seven....

I get both Prime and 7 Sydney here Davo.
I don’t remember seeing any difference between them.
The edge enhancement is usually applied in the camera as fare as I am aware.
It can be seen as a black/dark edge or hallo next to white lines or lettering, and its dammed ugly.
You can clearly see it on the deinterlacing screen shots you posted mate.

This is the difference that I saw between the two (even on my HD CRT I could see a difference):

PRiME - http://img84.imageshack.us/img84/1707/primeee0ll.png
Seven - http://img483.imageshack.us/img483/9716/74jt.png

That small difference in ringing, probably due to compression, is NOTHING compared to the DREADFUL edge enhancement.
Just look at the dark areas either side of the court marking lines.
They are nearly as wide at the white lines themselves, and should not be there. YUCK


Nice work with the animated .gif by the way dude.

Davo, those images are really interesting. I'm thinking it's more to do with scaling/ARCing PRiME have done rather than edge enhancement as such. Notice how the PRiME version is lacking in vertical detail only, horizontally it is pretty much identical. It looks like it's due to some slight scaling/ARCing PRiME have done. If you compare both of your images you can see that the PRiME version is slightly stretched vertically compared to the SEVEN one, but horizontally they are identical. Not sure why PRiME would do this, but it makes sense that after scaling vertically there would be a loss of detail vertically. The ratio of source lines to destination lines is no longer 1:1.

What do you think Davo? Owen?

Cheers,
Adam

The differences between the Prime and 7 images are INSIGNIFICANT.
Both are suffering from the worst edge enhancement I have seen in a long time, not to mention VERY low resolution, worse then Foxtel.
Every bright object has a dark halo around it, and I can see some bright halos around some dark objects as well, but they are harder to find in that scene.
I rate image quality as only 3-4 out of 10 for 576i.
If my DV camera provided images that bad, I would drop it in the bin.
VERY ordinary picture quality in deed for digital TV in 2006.

Sorry, I didn't like the animated gif... it created even more artifacts due to the lack of colours available in a gif

Anyway regarding the term "Edge Enhancement", I've always thought the halo ringing you see around edges to be a clear sign that Edge Enhancement was in use, as per the following links:

http://www.videophile.info/Guide_EE/Page_01.htm
http://www.videophile.info/Review/TPM/TPM_01.htm

Well, that's where I got my definition of Edge Enhancement from.. same as here:

http://www.dvdbeaver.com/film/productionrules.htm



I have seen similar cases with other broadcasts on PRiME SD vs. Seven SD, so it's not just limited to the Tennis, but alas, I seemed to have misplaced those other files... I haven't seen anything like that on their respective 576p channels...

The idea of edge enhancement to increase the contrast on edges, by making the edges of the bright objects brighter, and edges of the darker objects darker.
Image sharpening filters and SVM (Scan Velocity Modulation) on CRT TV’s produce the same effect.
That’s why SVM should be disabled on CRT TV’s.

A by product of this is “ringing”, which is the creation of a second edge or halo around objects. It can be induced by excesive sharpening-edge enhancement, but ringing can also be related to how compression systems handle images with edge enhancement –sharpening as fare as I know.

If you look at the example images here: http://www.videophile.info/Guide_EE/Page_01.htm
you can clearly see the effect.

In the tennis image, the white court marking should not have dark edges.
The white lines should merge smoothly into the pale green of the court.

Nasty edge enhancement is not restricted to SD.
Here is a capture from the Nine 1080i HD loop, showing very obvious edge enhancement.

[IMG]http://img142.imageshack.us/img142/6803/108itennise6qm.th.jpg[/IMG]

The 1712x1080 image size is due to the desktop res on my HTPC

I don’t know what kind of display this is supposed to look good on, but I sure as hell don’t have one.

Owen, I completely agree about the edge enhancement and, yes, it looks disgusting, and yes, it's clearly there in both versions (Seven and Prime).

I'm also interested in Davo's screenshots from the point of view of his original thoughts that Prime was worse than Seven. He is definitely right, though it doesn't look like additional edge-enhancement that Prime have applied, but rather something in their chain that is causing the feed to be scaled vertically slightly.

As already discussed, you can clearly see the blurring of vertical detail in the Prime version as compared to the Seven. Horizontally, both are virtually identical.

Fortunately the images Davo posted are very conveniently from the exact same source frame, so it is possible to compare them spatially. As I already said in the last post, the Prime version looks as though it is stretched slightly in the vertical direction. It would therefore follow that this operation would result in a loss of quality/detail vertically.

To illustrate what I am talking about I have prepared some screenshot compositions.

I took both of Davo's screenshots, desaturated them, them made the Seven one red and the Prime one blue. I then overlayed them with 50% transparency.

Take a look at the first composition, which is just an example to show what I am talking about regarding the overlaying of the two source images:
http://sub50.com/aaa/dba/prime_vs_seven_example.jpg

Since red and blue make magenta, everywhere that is common between the two images will look magenta. Differences will show as red or blue.

Now, take a look at the second composition, whereby I have aligned the two images so that the bottom white line of the tennis court is aligned between the two images:
http://sub50.com/aaa/dba/prime_vs_seven_1.jpg

Notice how although the bottom line is aligned, the very top line of the tennis court is mis-aligned, which you can see by the red and blue edges along the line (make sure your browser is not scaling the image so that the effect is not reduced).

Now, the final composition is the same as the last, except that the Prime image has been moved up so that the top line of the tennis court is now aligned. Notice how the bottom line is consequently mis-aligned, which again, you can see by the red/blue edges:
http://sub50.com/aaa/dba/prime_vs_seven_2.jpg

The amount I had to move the Prime vertically, in relation to the Seven image, between the top line of the tennis court being aligned and the bottom line, was two pixels. Since the distance between the top and bottom line of the court is 260 pixels, we can calculate the vertical stretch factor of the Prime image:

576 (full screen height) / 260 (distance between top and bottom lines) * 2 (displacement in pixels) =~ 4.43

Since (576 + 4.43) / 576 =~ 1.0077, this means that the Prime image is stretched vertically by 0.77% as compared to the Seven image.

Put another way, roughly 4 lines in the Seven feed are not being shown on Prime, with the 572 lines that are being shown, having been stretched to 576 lines. Unless extremely high quality scaling is used this results in distortion or loss of detail, and this can clearly be seen in the original screenshot of Prime that Davo captured.

The question is why are Prime scaling the Seven feed vertically? Davo captured both of these images from the SD digital output, so it's not as if it's been through an ARC like the analogue signal usually has.

You would hope that each and every one of the 576 lines from the Seven feed would be shown on Prime without any scaling being performed, except in special circumstances. To make matters worse, they are scaling vertically by 0.77% but not horizontally at all, which means that the aspect ratio when watching Prime is slightly out (by 0.77%), which although is not a huge amount, is still troubling!

If the tennis were a HD event, then this would be completely understandable, as both Seven and Prime may use completely different equipment to downconvert to SD, with each having slightly different characteristics. But in this case, we're only talking SD. The feed from Seven that Prime obtains for SD programming such as the tennis would almost definitely be an SD feed, one would assume. So why the scaling? It certainly degrades Prime's quality, as evidenced by Davo's screenshots!

Cheers,
Adam

Umm... how did you get rid of the arrows? Or did you find another screenshot of it?

In any case, here's another take on showing the differences:

http://img66.imageshack.us/img66/1557/composite3yz.png

Oh, and I finally found the other example that I was looking for:

PRiME SD - http://img334.imageshack.us/img334/29/primesd9ai.jpg
Seven SD - http://img334.imageshack.us/img334/8959/7sd6ev.jpg
Seven 576p - http://img461.imageshack.us/img461/5202/7hd8wz.jpg
PRiME 576p - http://img215.imageshack.us/img215/7945/primehd4ml.jpg

That was taken around September last year.. You can clearly see a halo on the horizon, which is what I've always believed to be Edge Enhancement. Funnily enough, if you compare the two SDs together, they appear to be identical in height, but the PRiME one has black bars on the sides, however if you compare the two 576p's together, you'll notice that the PRiME one has been bumped up by 3 or 4 pixels or so, though at least in this case it hasn't been rescaled. Sorry about the JPEG compression.. I was young and naive back then when I took the screenshots...

I didn't specifically get rid of them. They are lost because the red you used to draw the arrows was almost the same brightness as the green of the court! So once the images were desaturated (converted to black and white -- as mentioned in my post) the arrows could no longer be seen.


Yeah, and if you move the Prime one up/down slightly, so that the bottom line of the court is aligned, then you'll see the effect of the vertical scaling, but you've probably already tried that The only issue with calculating the difference using the effect you did is that the blurred vertical detail in the Prime version influences the results somewhat, but it's interesting nonetheless!


Oh yeah, I remember looking at those images when you originally posted them. It's interesting seeing them again in light of what we've been discussing above.

The black bars on the Prime SD one are just because Prime is broadcasting 704 x 576 as opposed to Seven who broadcast 720 x 576. As we've (I think it was with you) discussed before, this doesn't actually change the active picture area -- which is always the centre 704 x 576 even in the case of Seven who are broadcasting 720 x 576. The left-most and right-most 8 pixels can be pretty much ignored, and in the case of the Prime broadcast, they are not even being broadcast. BTW... in your grabs, it will be ~14.2 pixels of black on each side since you (or the DTV application) has upscaled the original 720 x 576 to 1024 x 576 in order to maintain aspect ratio.

Yep, there's definitely edge-enhancement in those grabs, though it seems to be fairly uniform in all 4 of them. There are fairly major differences in quality between the Seven and Prime versions (of both SD and HD versions), but I'd say they're more to do with different MPEG encoding and pre-filtering settings between the two networks, not to mention differences in other equipment that may be used in their chains.

Like you say, at least there's no scaling/aspect ratio differences in this case. Not sure what the go is with those tennis grabs. You didn't alter the Prime one in any way, other than adding the arrows?

I guess it's a possibility Prime didn't receive the tennis from Seven in SD. That would be quite odd I would have thought (and I still don't imagine it would be true), but if so, it would explain possible scaling differences since the equipment Prime would have had to use to downconvert back to SD from a higher format would have to de-interlace (assuming something like 1080i was used) and scale. This would result in a slightly different image than Seven's native SD one, not to mention the additional vertical blur that would potentially be added depending on how the de-interlacing was done. Anyway, this is all just theory -- I still struggle to imagine that Prime would have received and chosen to use an upconverted 1080i feed from Seven of the tennis, an SD event, over a high-quality native-resolution SD contribution stream.

Adam

Guess what your "difference composite" is really good for: demonstrating what I was saying about the Prime version having additional blur (which kind of looks a bit like a form of edge-enhancement) in the vertical direction only.

Notice how in your composite you can fairly clearly see all of the tennis court lines, except for one: the almost-perfectly vertical line which runs underneath the net along the centre of the court!

Here's another example: in your composite you can clearly see the edges of the referee stand, except for one edge -- the back of the stand -- which also happens to be the only perfectly vertical edge.

These examples show how the Prime image mostly differs from the Seven one in vertical detail only (the Prime one is somewhat blurred vertically). For this reason, perfectly vertical lines will not reflect a difference, since they are defined by horizontal detail, not vertical. Horizontal lines, or lines that are angled, will reflect a difference, as they do rely on vertical detail to be defined.

Also take a look at the letter "l" (lower-case L) in "Melbourne" at the bottom of the court. There is virtually no difference along the sides (vertical lines), but a huge difference along the top and bottom. Of course this is all somewhat influenced by the scaling issue with Prime, but nonetheless, part of it is due to the vertical loss of detail. To test that theory out, if you can be bothered, load up your composite again and try and move the Prime image such that the L in Melbourne shows the minimum amount of detail along the top and bottom edges, as well as the sides. I bet you'll find that even after doing this, the top and bottom sides will still be more visible than the edges.

Adam

Amazing!


Not really


That's odd.. my decoder says it's 720x576, but for other channels like Ten SD, it says 704x576 correctly...


My video program/decoder combo is at fault there.. It depends on what decoder I use.. sometimes, a 1440x1088 broadcast will become 1936x1088, and others do 720x576 when the source is 720x576... Personally, I can't stand to look at the squashed image, so I just choose a decoder that does the scaling automatically. It may not be accurate, but it certainly is much easier to look at.


I don't think so... I hope not... Let me just double check... Nope, I didn't alter it in any way.


Well, whatever they received, it certainly wasn't as bad as this feed:

http://img138.imageshack.us/img138/987/analogue0oa.png

7 showed that when they had technical difficulties with the audio on Digital, so they had to switch to a different feed, and when they moved to this other feed, it had no watermark, scoreboard or audio commentary.


Here, I made another one, this time, I tried matching the Melbourne:

http://img138.imageshack.us/img138/107/composite17uo.png

To be honest, I don't really care what PRiME do with their SD, as I can definately see a difference between PRiME and Seven's 576p, with the better quality going to PRiME's higher bitrate... now if they could just adopt the 5.1 that Seven's been using lately, I'll be 100% happy (Well, if they went up to 720p or 1080i, I'll be even more happier)

Ok, so they are broadcasting a full 720, but something in their chain is processing only 704, hence the loss of the sides.


Yeah, and notice how even though the Melbourne is matched as best as possible, you can still see more of a difference along the top/bottom of the 'L' as opposed to the sides.


Yeah, Prime's HD is supposed to be pretty good. I haven't really watched a lot of Prime HD, even though I can get it perfectly here on the Gold Coast. I have always just felt that Prime are not that ace compared to NBN, and now SC10 who have improved alot. I should give Prime the benefit of the doubt and check them out some more. They may well have improved, though judging by your SD grabs, I'm still pretty put off their SD!

Hey Davo, one final thing. Most of the screenshots you post are de-interlaced. I assume that's something your DTV app is doing. De-interlacing affects vertical resolution. What de-interlacing algorithm is being used, and is it the same one for all of the screen grabs you provide?

Adam

Man you notice everything... I'm pretty sure it was the same deinterlacing algorithm, but I'm not sure what was used... Anyway, here are the original, unadulterated frames:

Seven - http://img460.imageshack.us/img460/2669/79bh.png
PRiME - http://img460.imageshack.us/img460/3172/prime0wi.png

You can still see the differences between the two...

Thanks Dave

That's much better for accurate analysis.

Adam

It's exactly 3 meters. I understand the issues of human visual acuity/resolution I am a vision scientist in R&D for Zeiss, however I didn't sit down to do the math, I just expected HD to be obviusly HD vs DS, the thing is SD on my new TV is much better than my old CRT TV SD



Interestingly the Australian open was one of the first things I tried to view, I was surprised they didn;t broadcast things like this in HD



I am generally quite impressed with the quality of images from the LG, both clarity and the complete lack of motion blur, it really has a nice display. I was just surprised how little difference there was 90% of the time between HD and SD broadcasts...I can't even see the difference between SDi and SDp transmissions...however as I noted, occasionaly I see a HD image and it's quite stuning, the 9 loop for example.

Thanks Scott

Did you watch Lethal Weapon 4 last night? Huge difference between SD and HD there... and it's not just because the HD one was in the OAR either...

The comercial HD braodcasts are hardly ever in true HD. They are either upscalled or plain and simple the same signal. The only true HD broadcast i have seen is the Nine loop which is now gone. But that was beautiful.

While im at it ill gripe about Sevens HD 576p is hardly HD come on guys.

EDIT: So all in all you cant really compare untill there is some real HD footage.