Emulator

Thanks for the clear and concise bug report.

I'd like to add that playing on a modern 16:9 LCD (Wii through component cables) and then setting the aspect ratio to "Original"/"Pixel Perfect" on the TV itself gives me a similar result to Dolphin, which means this really is done on purpose, to compensate for the expected CRT stretch of the time. Dolphin outputs the same signal as a GameCube/Wii, we're simply not seeing it how we would on an old CRT.

No, that's not true. Modern TVs do a near-perfect good job of replicating "the CRT stretch". Actually they are more accurate than a typical CRT, which would often be slightly off due to analog electronics.

If it's showing up the same in both Dolphin and a LCD tv, then it's not going to show up any differently on a real CRT.

They do replicate that, when set to 4:3. However, my LCD TV has a pixel perfect option that deliberately ignores that. It looks right when set to 4:3 on the LCD, and it looks right (at 4:3) on my CRT.

(the picture shows as much)

I've also tested it in 14:9 (LCD), as suggested by @eckso in the other post, and it looks very wrong. It only looks right in 4:3 mode, on both LCD and CRT.

@phire what I'm looking for here isn't even a game fix. Just an option to stretch to 4:3 in the emulator itself. The current "Force 4:3" option doesn't force 4:3, it forces square pixels. When using custom shaders to force 4:3, these games look perfect.

@phire It's neither, in my opinion. Dolphin is correctly emulating the internal signal of the GameCube, likely what you'd get if you used a capture card, and also what I get when I use pixel perfect mode on my LCD. However, as shown by the photo, circles show up as circles on a CRT, which I believe means the game was developed with stretching in mind. I can snap more pictures of circular elements in the UI (the ring icon in gameplay, for example, copyright symbols in text, I've shown all of these in the forum topic I linked to earlier today) to show how it looks on the CRT. And, as I've said earlier, I have two more games that behave in exactly the same way (ovals in Dolphin and pixel-perfect mode LCD, proper circles on my CRT). I just want an emulator-wide option in Dolphin to stretch games to 4:3 (and maybe rename the current "Force 4:3" option to "Internal aspect ratio" or "1:1 pixel aspect ratio").

Look at the photos I posted, then. The CRT one clearly shows a circle where Dolphin displays an oval, and the dumped texture is also a perfect circle. That's why I raised the issue in the first place: because I felt the ovals I was seeing in Dolphin weren't the same as what I saw when I originally played this game, so I went back to the GameCube, confirmed and photographed it. I'm less peeved about it now because another user gave me a custom shader that stretches the picture to 4:3 and makes everything circular, but I still thought it should be fixed in the emulator itself (or at least give users the choice). If the devs think this is the proper behavior, though, I won't insist any longer.

The CRT one clearly shows a circle where Dolphin displays an oval

Because on your CRT, you are using the PAL version of the game.

While you apparently have an NTSC version of the game running in dolphin. Did you mix up the versions while dumping?

The game is broken. In 50Hz mode (which is the default for PAL) it has the correct aspect ratio, the menu items appear circular. But in 60Hz, it has the incorrect aspect ratio with non-circular menu items.

If you boot the PAL version of the game into PAL60 mode (hold B while booting to get a video mode selection menu), it also replicates dolphins result of the NTSC version of the game. If you correctly dump the PAL disc and load it into dolphin, you will find that replicates the result of the PAL disc on real hardware, with circular menu items.

Nope. It's PAL60. I always use 60 Hz. And I checked. All pictures were captured at 480i

The Dolphin version is NTSC because I tried that one after noticing the issue in the PAL version initially. I tried NTSC because I suspected it may be a regional issue, but it wasn't

When I get home, I'll photograph both modes on my TV, to dispel any doubts. But both display the same picture, despite being different resolutions

Do you know what the technical differences are between your modern TV's 4:3 mode and pixel perfect mode? (Perhaps the manual has a description of the modes?) Since lines of analog video don't contain pixels, I was assuming that the name of this "pixel perfect" mode couldn't be referring to how the lines are stretched and that it thus probably was some kind of setting that controls overscan, but if the wideness of things looks different between the two there must be some sort of difference.

JosJuice wrote:

Do you know what the technical differences are between your modern TV's 4:3 mode and pixel perfect mode? (Perhaps the manual has a description of the modes?) Since lines of analog video don't contain pixels, I was assuming that the name of this "pixel perfect" mode couldn't be referring to how the lines are stretched and that it thus probably was some kind of setting that controls overscan, but if the wideness of things looks different between the two there must be some sort of difference.

I do. Pixel-perfect mode was originally meant for DVD playback. It assumes analog signals use the full 720-point spatial resolution limit of old analog signals, resulting in a digitized 720×480 image for NTSC or PAL60 signals and 720×576 for PAL. It then scales this signal to a 1440×1080 space in the center of the display, meaning horizontal resolution is fully preserved, as pixels are doubled with no blur, whereas vertical resolution is scaled normally (with bilinear filtering). This yields a perfect 4:3 image for DVDs that use the full SD resolution. Other sources, which leave blank horizontal space on either side of the picture (analog-converted 704×480 was common, for example, for SD digital camcorders), have that blank space treated as black pixels, which means images appear squeezed vertically. CRTs would often ignore that blank space and stretch whatever was left to 4:3, even before overscan. Developers would often rely on that (or predict that) and make games slightly anamorphic to compensate. My LCD's 4:3 mode replicates that effect. It ignores blank space, stretches whatever's left to 4:3, and then slightly crops the picture. I assume some CRTs would treat the blank signal as black too, which would explain @phire having confirmation that there are ovals on CRTs as well. But I've provided photo and video proof that mine doesn't, and in 60 Hz mode.

I'm sorry... Your TV does what? Can you please provide the brand/model number so I can look up the details.

CRTs would often ignore that blank space and stretch whatever was left to 4:3, even before overscan

This is simply not true. No TV in the gamecube era did anything like this. You are just making wild speculation that is competly untrue. I've done extensive research into the operation of CRT TVs in order to get dolphin's aspect ratio implementation correct.

Developers would often rely on that (or predict that) and make games slightly anamorphic to compensate.

While your modern TV might have such a mode, your TV didn't exist in the gamecube era. Nothing that behaved like that existed.

No developer was making decisions on what might result in the best image quality on some weird "pixel perfect" mode on some futuristic TV.

What happened instead is that some developers made mistakes and assumed square pixels. Or simply didn't care due to rushed deadlines on low-quality ports.

I'm sorry if I wasn't clear enough. I'll try to organize and break it down better:

1 - I meant devs optimized for CRTs, obviously. I may have faith in their skills, but not to the point where I think they predict the future.

2 - My CRT TV is OLD. It's been in my house for at least 15 years, likely more. It has no adjustable display modes besides typical 4:3 and 16:9, and it's the one in the videos (always set to 4:3, of course, it's a 4:3 TV and the 16:9 mode is letterboxed). It's the one I took the tape measurements in, showing perfect circles in PAL60 mode (5.7×5.7 cm) and unnoticeably wider circles in PAL mode (5.8×5.6 cm). As seen in the videos I attached. I can find a way to test the NTSC version as well if you think it might not look the same as PAL60.

3 - My "modern" (early 2013, probably manufactured in 2012) LCD is the one with the two different scaling modes. I don't have the model number on hand, but it's a 40" 3D 1080p Sony BRAVIA. I can check the proper model later. It has 5 scaling modes: pixel-perfect, 4:3 optimized, zoomed 4:3, 14:9, 16:9. Language settings can make names vary (mine's not in English). It produces the same result as the CRT in optimized 4:3 mode (circles) and the same result as Dolphin in pixel-perfect mode (ovals that are ~10% stretched).

I am not in any way devaluing your research, and you probably know a lot more than I do about the inner workings of video signal. But the fact remains that I have a CRT showing circles in PAL60 mode, and that I can replicate both that and Dolphin's output on my LCD. And I have sent you video proof.

I really hope I'm not coming across as harsh in any way, and I'm trying to back up my statements with video proof whenever possible to avoid doubts and confusions.

Can you check the Linearity Test Pattern from the 240p test suite?

https://artemiourbina.itch.io/240p-test-suite

Make sure it shows the correct thing in both NTSC and PAL modes.

https://files.extremscorner.org/gamecube/screenshots/linearity.png

Of course. I'll test everything when I get back home, on CRT and both LCD scaling modes, snap pictures/videos of everything, and I'll get back to you.

From what I can see measuring your photos:

CRT PAL: 1.04:1
CRT NTSC: 1.03:1

So your CRT is out of calibration by 3-4% in both modes. The distortion isn't even across the screen, the grid view would probably show that better.

LCD PAL: Almost exactly 1:1
LCD NTSC: 1.04:1

Well... I don't know what is going on with your LCD's NTSC handling, and weird that it almost matches the CRT

phire wrote:

From what I can see measuring your photos:

CRT PAL: 1.04:1
CRT NTSC: 1.03:1

So your CRT is out of calibration by 3-4% in both modes. The distortion isn't even across the screen, the grid view would probably show that better.

LCD PAL: Almost exactly 1:1
LCD NTSC: 1.04:1

Well... I don't know what is going on with your LCD's NTSC handling, and weird that it almost matches the CRT

It could be camera distortion, couldn't it?
I also find it weird that the test suite signal is recognized as different from the game signal by the LCD, even when both say 480i (it locks me out of some scaling options, as I said above).
I honestly don't know what to make of this. I understand that you don't want to implement a game fix based on my report alone, especially without fully understanding what's going on here. However, would it hurt to have a global 4:3 stretch option on the emulator? So users could try the current one and that one and decide which one looks better? As I've said before, I've noticed a few games that suffer from this, and even if I can't fully prove that they display properly on old CRTs (I accept that photos/videos of my CRT alone aren't enough), it would be a harmless option to have, no?
Thank you for all your trouble.

It could be camera distortion, couldn't it?

well, if it's camera distortion, then the same camera distortion would be impacting photos of Sonic Adventure 2: Battle. Feel free to bring out a tape measure if you are unsure.

I also find it weird that the test suite signal is recognized as different from the game signal by the LCD

Make sure you are setting the video mode inside 240p test suite to "480i scaled 240p assets (NTSC)" and "576i scaled 264/240p assets (PAL)" video modes. By default it does 240p/288p.

However, would it hurt to have a global 4:3 stretch option on the emulator

It does slightly the wrong thing in most games, and it can get very wrong in the extremes. For examples the widescreen cutscenes in Rogue Squadron 3 get stretched all the way from 2:1 to 4:3 and look ridiculous.

This is more a topic for i9024. I think eckso's suggestion of a post-processing shader to fix it is a good way to go for now.

phire wrote:

It could be camera distortion, couldn't it?

well, if it's camera distortion, then the same camera distortion would be impacting photos of Sonic Adventure 2: Battle. Feel free to bring out a tape measure if you are unsure.
True. I'll measure everything tomorrow to be sure. I might've been holding the camera wrong or something. The test suite's circles looked good to me, but I may not be noticing a 4% stretch (like I hadn't noticed the small difference — nowhere as big as in Dolphin — between the circles in PAL and PAL60 SA2:B).

I also find it weird that the test suite signal is recognized as different from the game signal by the LCD

Make sure you are setting the video mode inside 240p test suite to "480i scaled 240p assets (NTSC)" and "576i scaled 264/240p assets (PAL)" video modes. By default it does 240p/288p.
I used those options. Which makes it even weirder.

However, would it hurt to have a global 4:3 stretch option on the emulator

It does slightly the wrong thing in most games, and it can get very wrong in the extremes. For examples the widescreen cutscenes in Rogue Squadron 3 get stretched all the way from 2:1 to 4:3 and look ridiculous.
I get that. As a user, I'd like to be given the choice, but I understand that many people would probably enable it and then complain when faced with those extreme examples.

This is more a topic for i9024. I think eckso's suggestion of a post-processing shader to fix it is a good way to go for now.
Yeah, another user sent me a custom-made shader and most problematic games I've come across look fine with it, so I have my fix for now.
Thank you again for all your help/attention/trouble!

Sorry, the quotes came out wrong. I'm on my phone and must have missed some ">" signs. But it should be understandable. Thanks again!