CFA: Check your TV resolution with fugly images

Rolf N

Recurring Membmare
Veteran
Note to mod: technically this is about HDTVs so it might fit in the output device section. However, as consoles are the likely vehicle used to throw the test images on screen in a controlled manner, with and without reasonable scaling hardware, that is the audience I seek input from.

CFA's supposed to mean call for action.
res-test640x360.jpg


That's one of a set of images I generated with a little program I wrote. All lines in the image are doubled up, one pixel wide with a one-pixel gap between them. The images are rendered with 8x8 ordered grid supersampling and the downsampling has been compensated for gamma (2.0). As you can probably see on the monitor you're staring at right now, as long as the display device can resolve all pixels that are thrown at it, there'll be pretty clear one-pixel gaps between all line pairs. You can use this to tell whether or not the display device can fully resolve the resolution you're using, or if it can't (and starts bleeding together pixels). The observation is separable between vertical and horizontal, which is nice I guess. It's also possible to tell if your aspect ratio is borked, resulting in non-circles.

I'd like to ask for a little help here. Please, if you have an HDTV and a means to feed it with jpegs, try out how far the display will carry you. The usable resolution of interlaced output modes should be especially interesting. You should start at trying the advertised native resolution of your display, but I encourage you to also try a little higher and a little lower. I have all the standard 16:9 resolutions covered, plus a few in-between ones. Here's the selection again:
http://zeckensack.de/misc/res-test/
Display the images so that they fit on screen. Do not zoom in however, as it defeats the purpose. When you can still discern line pairs (with a nice black gap and all), the display you're using has at least the resolution indicated by the file name.

Of course I am an ultimately evil person and as such I have a specific and devious plan for this thread, which is finding an Xbox 360 owner with one of them 1080i-only tubular TVs, who is willing to explore the max useable image resolution of that (1080i) display mode. My opinion on this matter, as posted a few hundred times, is that it will be well below 720 lines. But do try it out please.

I still have that program, and should the need arise I can generate more images of that type in arbitrary resolutions and aspect ratios, and I can also compensate for arbitrary display gamma -- 2.0 is a nice starting point but probably not exact. If you need some specific parameters, just say the word.

Random observations:
  • The Wii photo channel has "overscan" issues, crappy scaling, and doesn't support grayscale JPEGs or progressive JPEGs
  • Netbeans 5.5 rocks as an IDE ... for C++ development no less!
  • ATI fglrx drivers are rubbish. As in GL_RGB not working as a glReadPixels format on an RGB visual :???:

Oh, and something informative for a change:
The Wii photo channel has [strike]no trouble resolving the 848x480 image with really really black gaps between the vertical pairs. That, in conjunction with the absence of any banding in the photo channel, means two things: 1) the Wii's widescreen is not (restricted to) anamorphic junk! 2)The Wii's framebuffer (backbuffer, not including z buffer) eDRAM is at least 1200kiB in size.[/strike]
Oh noes, scratch that, I had too many small images on the card and got stuff mixed up. The top pristinely useable resolution, out of my bunch, is 640x360. That's with 480i (I don't have component cables yet) displayed on an LG 32LC2R.

Having a low useable resolution does not mean the same as having a low render resolution! Splotching together many pixels to one is not the desired way to treat pixels that have been carefully transported to the display in separation, but even so it's not all bad; it leads to the same effects as supersampling over the (low) output resolution. For gaming purposes that makes "480 useable lines of resolution" with an absurdly high input resolution much better, and much less shameful, than rendering directly in 480p and displaying that perfectly. For movies the issue is obscured by the infinite supersampling automatically present in all material captured by cameras, and the usually excellent anti-aliasing levels in CGI.
Still, resolution is a display device's virtue in itself and, all else being equal, higher=better.
 
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JPEG compression doesn't sound like a good idea for these types of images, though.
Agreed. Unfortunately PNGs still aren't as portable.
But then AFAICS the JPEG compressor did a good job on these (I selected a pretty high quality of course). They are quite simple after all. And you're not supposed to zoom in ;)
 
Your probably not interested in LCDs for comparison. But I was curious myself so here you go.

Sony Bravia KDL40V2500 (JP Model)
IMG_2330.jpg


Dell 2407WFP
IMG_2349.jpg



I didn't realize how dirty your jpeg was until I photo graphed it. These are the res-test1920x1080.jpg at the panels native settings BTW.
 
Your probably not interested in LCDs for comparison. But I was curious myself so here you go.

Sony Bravia KDL40V2500 (JP Model)
<...>
Dell 2407WFP
<...>

I didn't realize how dirty your jpeg was until I photo graphed it. These are the res-test1920x1080.jpg at the panels native settings BTW.
Thanks.
You sure about the "dirty" thing? Because I can't see anything unusal -- granted, my laptop LCD is kinda crappy so that doesn't mean there isn't anything unusal. The distance between the circle pairs is one pixel all around, and the image is anti-aliased, so there will be lots of shades of grey in between them at most angles outside of the main x/y axes. That's the nature of anti-aliased circles ;)

I could push the circles farther apart like this:
res-test512x288_wg.jpg

(I could do the same with the other lines as well)
But that's cheating. You'll have a nicer gap between the circles, yes, but you'll also have that when you're above the effective display resolution, because it's now two pixels across.

edit: Ah haa! Nevermind, I can see it now.
 
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Yes your jpeg compression created all sorts of new data. You should use gif instead. I bet the file size will be smaller than a jpeg because lzw compression will kick ass on this type of graphic.
I have some of them as lossless png, which are not only lossless (duh! ;)) but also smaller than the jpegs. I didn't release them that way because I had enough trouble with getting anything to show up on the Wii, and I wasn't sure which image formats would work on a 360, or maybe even one of those TVs with built-in card readers.
This jpeg sub-type is what your regular digital camera spits out, so it should work on anything really.
I doubt the artifacts will ruin the results, which are just non-scientific inspection after all, and I like having the larger audience.
 
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I could push the circles farther apart like this:
How about you make the outer left circle just touch the left, top and bottom screen edges (and correspondingly the same with the right)? This way ione can check how much is lost due to overscan...

This would be extremely useful IMO. Overscan on flatpanels seem to be very arbitrary and sometimes huge amounts of screen estate is simply lost.

&Thanks!

Peace.
 
... displayed on an LG 32LC2R.

Soooorry so much for going of topic, but I would really really appreciate your opinion on this LG set. I was thinking that this weekend will be the time to jump on the HDTV bandwagon and this set, or actually a bit different model, the 37LC2RB, is the one that for now is the most likely purchase.

To get on topic again, if I find the time this weekend and get this set as well as a 360 I will try this little trick of yours, but then again maybe you have already done it with your set...
 
How about you make the outer left circle just touch the left, top and bottom screen edges (and correspondingly the same with the right)? This way ione can check how much is lost due to overscan...

This would be extremely useful IMO. Overscan on flatpanels seem to be very arbitrary and sometimes huge amounts of screen estate is simply lost.

&Thanks!

Peace.
I had that, and I can do it again but will keep it a seperate thing.
The thing is that I did lose the outer parts of the circles to overscan on my TV, but those are the only parts where there is any chance of finding true black in the gap, so I pulled them inwards to make that visible again.

I'll whip up some with the circles extending all the way to the screen edges in a short while.
 
Soooorry so much for going of topic, but I would really really appreciate your opinion on this LG set. I was thinking that this weekend will be the time to jump on the HDTV bandwagon and this set, or actually a bit different model, the 37LC2RB, is the one that for now is the most likely purchase.
I really can't offer much of an opinion right now. All I have viewed on the screen are SD inputs. Freakin' composite from the Wii and RGB from a PStwo. I forgot to grab a VGA cable so I couldn't even hook my PC up yet. I have no HD broadcasts (no broadcasts at all actually, not even a basic antenna), no upscaling DVD player or whatever other device to feed an HD signal to the screen. That's why you shouldn't rely so much on my opinion -- I'm very happy with the TV atm but I have not yet seen the device doing what it was built to do: display HD feeds.

What I can say is that it looks nice, the sound quality is actually good, you can turn off all the "image enhancements", even fine control a small subset if you so desire, it has all the inputs one would hope for, and it's just dirt cheap for its size. The physical design is excellent. There's an extra composite+stereo audio input on the left side, so you don't need to crawl behind the living room to quickly hook something up, and the basic controls are on the right screen edge.

The control options are excellent. There are some idiosyncrasies with the menu navigation but you can do everything. You get a complete, separate configuration for every input. There are direct aspect ratio and input selectors on the remote control. It's not exactly what I expected, but it makes sense and now that I've learned how to use it I'm fast enough with whatever I need to do.

It's heavy. 25kg. And it says it can draw up to [strike]100W[/strike]140W. I guess that's to be expected at that size.

It takes some wrestling with the settings but the colors can be made to look reasonable, it can produce a good enough black (says someone who's still holding on to a 19" CRT and a 17" CRT) and it can fire enough brightness to burn your eyes out at 1 meter, if you want that.

I have seen some minor deinterlacing glitches, but it really only happens when a high-contrast outline suddenly starts moving fast, which isn't seen so often. I think I can live with that. The framerate and latency feel correct. I played F-Zero GX again (60fps, ultra-high-speed racing) and I didn't get the impression it was any worse than on the old Sony CRT thing.

Hope that helps. Just keep in mind that I can currently tell you nothing about the behaviour with HD resolutions.
Platon said:
To get on topic again, if I find the time this weekend and get this set as well as a 360 I will try this little trick of yours, but then again maybe you have already done it with your set...
Umm, no, I can't. My new TV isn't 1080i-only, unless I'm terribly mistaken it should support 720p. My evil scheme concerns only those TVs that support 1080i but do not support 720p.
 
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Why would you use the wii to check tv resolutions? The wii's photochannel downsizes jpeg images/quicktime movies so they won't be at their native res, plus the output of the wii is a max of 640x480 anyway.
 
I really can't offer much of an opinion right now. All I have viewed on the screen are SD inputs. Freakin' composite from the Wii and RGB from a PStwo. I forgot to grab a VGA cable so I couldn't even hook my PC up yet. I have no HD broadcasts (no broadcasts at all actually, not even a basic antenna), no upscaling DVD player or whatever other device to feed an HD signal to the screen. That's why you shouldn't rely so much on my opinion -- I'm very happy with the TV atm but I have not yet seen the device doing what it was built to do: display HD feeds.

What I can say is that it looks nice, the sound quality is actually good, you can turn off all the "image enhancements", even fine control a small subset if you so desire, it has all the inputs one would hope for, and it's just dirt cheap for its size. The physical design is excellent. There's an extra composite+stereo audio input on the left side, so you don't need to crawl behind the living room to quickly hook something up, and the basic controls are on the right screen edge.

The control options are excellent. There are some idiosyncrasies with the menu navigation but you can do everything. You get a complete, separate configuration for every input. There are direct aspect ratio and input selectors on the remote control. It's not exactly what I expected, but it makes sense and now that I've learned how to use it I'm fast enough with whatever I need to do.

It's heavy. 25kg. And it says it can draw up to [strike]100W[/strike]140W. I guess that's to be expected at that size.

It takes some wrestling with the settings but the colors can be made to look reasonable, it can produce a good enough black (says someone who's still holding on to a 19" CRT and a 17" CRT) and it can fire enough brightness to burn your eyes out at 1 meter, if you want that.

I have seen some minor deinterlacing glitches, but it really only happens when a high-contrast outline suddenly starts moving fast, which isn't seen so often. I think I can live with that. The framerate and latency feel correct. I played F-Zero GX again (60fps, ultra-high-speed racing) and I didn't get the impression it was any worse than on the old Sony CRT thing.

Hope that helps. Just keep in mind that I can currently tell you nothing about the behaviour with HD resolutions.

Cheers, thanks a lot for the input, I highly appreciate it and strangely I am not so interested in the HD feeds, I have actually seen this set is stores doing them and it looks really good. It was more about how the controls are, black levels and stuff like that, I will after all mostly use it for viewing sdtv broadcasts so it is interesting to know how it handles that. The reason that I am very much looking into this set is one of the reasons you mentioned, the connections, it seems to have evrything. It is amazing how few TV actually have HDMI,component & VGA all at the same time, especially at the price range of this set, is it really that big of an expense to have a VGA input for example? I have checked this set in stores and compared it to other sets and it seems great, the only thing I could notice was that in very dark areas of an image it could loose some detail but that might be possible to be tweaked as it was not possible in the store to control the advanced XD settings, good to hear that you can control more or less everything. Any good sites for LCD TV calibration?...
 
Why would you use the wii to check tv resolutions?
Because that's all I have :)
Fox5 said:
The wii's photochannel downsizes jpeg images/quicktime movies so they won't be at their native res, plus the output of the wii is a max of 640x480 anyway.
I wasn't so sure about the resolution, and still want to wait for a rerun with component cables (480p) before settling that down for myself. The scaling is not an issue for this kind of test. Minification is bad, but I don't want to use any minification here. The images should just fill the screen, one output pixel per input pixel. If the pixels aren't clear I know I'm over the limit and can retry with a smaller image. So absolutely no issue with scaling.
In fact the Wii makes the images a little bigger than they should be due to overscan.
 
Cheers, thanks a lot for the input, I highly appreciate it and strangely I am not so interested in the HD feeds, I have actually seen this set is stores doing them and it looks really good. It was more about how the controls are, black levels and stuff like that, I will after all mostly use it for viewing sdtv broadcasts so it is interesting to know how it handles that. The reason that I am very much looking into this set is one of the reasons you mentioned, the connections, it seems to have evrything. It is amazing how few TV actually have HDMI,component & VGA all at the same time, especially at the price range of this set, is it really that big of an expense to have a VGA input for example? I have checked this set in stores and compared it to other sets and it seems great, the only thing I could notice was that in very dark areas of an image it could loose some detail but that might be possible to be tweaked as it was not possible in the store to control the advanced XD settings, good to hear that you can control more or less everything. Any good sites for LCD TV calibration?...
Don't know. I have more impressions though if you're interested.
Black levels ... I have to retract that slightly. I hadn't really used the screen with low ambient light, but now I have, and the blacks aren't that good. Tolerable yes, but good? No. No.
I have fired up God Of War again because there was some discussion about that *cough* and that's where I started to see ghosting. I don't know why it's so pronounced there, maybe because of the choice of colors, maybe because it's progressive scan, but it is very noticeable. No problem at all in other games (F-Zero, Metroid Prime, Star Ocean 3, Red Steel, Zelda) as far as I can tell.

I finally picked up the cable today and can only say that this TV is wonderful as a VGA monitor. No overscan at all. You can configure the TV to try to achieve a 1:1 pixel mapping for 1366x768 pixels (native panel res), 1360x768 (Radeon driver's favourite res) or 1280x720 pixels. It'll add the black bars as necessary and give you a really sharp 1:1 pixel perfect image.
I had slight ghosting again in VGA mode when I ran 3DMark 2001. Don't laugh, it was a Radeon 9200 hosting the show.

All in all I'm still very happy with it, but I can see it has its limitations.
 
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Don't know. I have more impressions though if you're interested.
Black levels ... I have to retract that slightly. I hadn't really used the screen with low ambient light, but now I have, and the blacks aren't that good. Tolerable yes, but good? No. No.
I have fired up God Of War again because there was some discussion about that *cough* and that's where I started to see ghosting. I don't know why it's so pronounced there, maybe because of the choice of colors, maybe because it's progressive scan, but it is very noticeable. No problem at all in other games (F-Zero, Metroid Prime, Star Ocean 3, Red Steel, Zelda) as far as I can tell.

I finally picked up the cable today and can only say that this TV is wonderful as a VGA monitor. No overscan at all. You can configure the TV to try to achieve a 1:1 pixel mapping for 1366x768 pixels (native panel res), 1360x768 (Radeon driver's favourite res) or 1280x720 pixels. It'll add the black bars as necessary and give you a really sharp 1:1 pixel perfect image.
I had slight ghosting again in VGA mode when I ran 3DMark 2001. Don't laugh, it was a Radeon 9200 hosting the show.

All in all I'm still very happy with it, but I can see it has its limitations.

Thanks once again for the impressions. I am sure it has it limitations, the whole LCD technology right now has limitations, but from what I can gather in that price range were this TV is, I do think you get the most bang for the buck, and it feels a bit stupid to pay like three times more for the really high end stuff, when the benefits are quite minimal really and most likely in a couple of years those sets will not be that great anyway...
 
Very interesting test. I have one of those 480i,p/1080i only CRT (KV-36XBR400) tvs that you're interested in getting results from . I'll try out the 1920x1080, 848x480, and 960x540 files. Any others in particular you think I should try? I'll be using a PS3 to do the testing, unless, for some reason, you feel I should use a 360. Maybe I'll try them both out. Results by late tonight (EST).
 
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