MiSTer FPGA Forum

Posted: **Sat Jul 18, 2020 8:30 pm**

Anone has any experience with MiSTer outputting 1440p on a Samsung Q80T?

https://www.rtings.com/tv/reviews/samsung/q80t-qled

I wonder if 1440p works on that setup and how's the overall quality?

Posted: **Wed Jul 22, 2020 7:34 pm**

Ok, so I've ended up getting a Samsung TU8000. According to RTings.com (https://www.rtings.com/tv/reviews/samsung/tu8000) it should support 1440p@60Hz, but it was a no go with MiSTer.

Is there anything else I could try with video_mode in order to see if 1440p will actually work of if the TV doesn't support it at all?

Edit: Other that not being able to get 1440p to work, the TV is great and input lag is just a frame (same as my BenQ 27" "gaming monitor"

)

: qvTAfXc.jpg (161.51 KiB) Viewed 7732 times

Posted: **Wed Jul 22, 2020 9:16 pm**

It's me again on this one-man-thread

So I've plugged in a PC on my TV and indeed it supports 1440p:

: 5ynuK2h.jpg (120.79 KiB) Viewed 7732 times

The issue seems to be the horizontal resolution: The TV seems to support 2560 but not 1920.

Since MiSTer doesn't seem to support 2560 I can then say that it won't be possible to use MiSTer on this TV.

Posted: **Thu Jul 23, 2020 10:00 pm**

I just got a q90t, the low input lag is amazing.
Did you turn off the "Game motion plus" setting? I think it is buried under external device settings or something like that, it adds an extra frame of input lag. I don't have a CRT to test with, but I have a monitor with 10ms input lag according to displaylag.com and the tv has no more lag than that from my test. rtings.com also says around 10ms for these tvs.

I think if you perform the same input lag test that these websites use on a 60hz crt you should get 8.33ms(it measures the time for the image to change in the middle of the screen), so it should only be about 2ms more for these tvs.

As a test I tried out Donkey Konga on my gamecube and it was actually playable on the q90t, on my older tv that had about 4 frames of lag over my monitor, it was near impossible to do well.

Posted: **Thu Jul 23, 2020 11:52 pm**

Does your TV support 1920x1440?

Posted: **Fri Jul 24, 2020 2:08 pm**

Unfortunately I had to exchange mine, there was what looked like dust trapped under the screen, it looked like a dead pixel but it was irregularly shaped. The store didn't have any so they need to order one. I'll see if it can do 1920x1440 when I get the replacement!

Posted: **Fri Jul 24, 2020 8:27 pm**

So I'm super happy to announce that I could get pixel perfect 5x vertical scaling with MiSTer and my 50" Samsung TU8000.

I was surprised that my TV supports 1920x1200@60Hz, so this is my MiSTer.ini:

Code: Select all

[MiSTer]
vsync_adjust=0
video_info=5
video_mode=1920,128,208,336,1200,1,3,38,193160
video_mode_ntsc=1920,128,208,336,1200,1,3,38,193160
video_mode_pal=9
vscale_mode=1
browse_expand=0
ypbpr=1
logo=0
;forced_scandoubler=1

[GBA]
vsync_adjust=2

[GameBoy]
vsync_adjust=2

[MSX]
vsync_adjust=2

[SMS]
vsync_adjust=2
video_info=0

[NeoGeo]
vsync_adjust=2

[SNES]
vsync_adjust=2

[Genesis]
vsync_adjust=2

[MegaCD]
vsync_adjust=2

[NES]
vsync_adjust=2

[TGFX16]
vsync_adjust=2

Vertical scaling is now perfect and I get no vertical shimmering with this resolution and vscale_mode=1 (integer scale only). I've got small black bars (around 1cm thick) on top and bottom edges, but they are not bad at all!

Horizontal scaling needs some interpolation (just like the Framemeister does), so I've just enables Nearest Neighbor horizontal only interpolation in cores:

Code: Select all

Misc/Horz Interpolation Only/Gaussian_Sharp_NN_05.txt

vsync_adjust=2 works in all cores that are critical to me, so this is a summary of what I'm getting with MiSTer and this TV:

- No added lag (aside of the TV's 1 frame lag) because MiSTer is not using a framebuffer (vsync_adjust=2)

- Pixel perfect 5x vertical scaling at the expense of 1cm borders on both top and bottom edges

- Satisfactory horizontal interpolation by using horizontal only nearest neighbor filter (scanlines filters work great as interpolation as well)

What can I say now aside that I'm super satisfied?!

This TV scales to 1200p so well that I don't think I need 1440p anymore!

Posted: **Fri Jul 24, 2020 9:42 pm**

Only issue so far I could find is with the NeoGeo core. I've got screen tearing on vsync_adjust 1 and 2. On vsync_adjust 0 I get some screen tearing but more rarely. I didn't notice that on any other arcade cores with vsync_adjust=0 and console cores with vsync_adjust=2.

Posted: **Sat Jul 25, 2020 11:31 am**

So I was dumb on saying that 1920x1200 is Pixel Perfect because it's not a 4:3 5x integer multiple of 320x240.

So the real 4:3 5x pixel perfect resolution should be 1600x1200@60Hz that my TV happily accepts:

Code: Select all

video_mode=1600,64,192,304,1200,1,3,46,162000

This is now the contents of my MiSTer.ini file, if anyone is interested:

Code: Select all

[MiSTer]
vsync_adjust=0
video_info=5
video_mode=1600,64,192,304,1200,1,3,46,162000
video_mode_ntsc=1600,64,192,304,1200,1,3,46,162000
video_mode_pal=9
vscale_mode=1
browse_expand=0
ypbpr=1
logo=0
;forced_scandoubler=1

[GBA]
vsync_adjust=2

[GameBoy]
vsync_adjust=2

[MSX]
vsync_adjust=2

[SMS]
vsync_adjust=2
video_info=0

[NeoGeo]
vsync_adjust=2

[SNES]
vsync_adjust=2

[Genesis]
vsync_adjust=2

[MegaCD]
vsync_adjust=2

[NES]
vsync_adjust=2

[TGFX16]
vsync_adjust=2

Everything looks great now and that even fixed the tearing issues with the Neo Geo core with vsync_adjust=2. Now everything looks perfect!

However, as there's no free lunch, true 4:3 5x resolution has added one more lag frame on my TV. Two frames of lag now, but with perfect 5x scaling:

: oSaeAYN.jpg (95.58 KiB) Viewed 7731 times

This is still better than scaling with something like a Framemeister (who always add lad because of its frame buffer). So in this setup I have only the two frames of lag added by the TV, as MiSTer doesn't add any with vsync_adjust=2.

This is pretty awesome I would say!

Posted: **Sat Jul 25, 2020 2:05 pm**

Did you check for that "Game motion plus" setting? If it is on, you can save another frame of lag by turning it off. It is in the settings under General -> External Device Manager -> Game Mode Settings.

Posted: **Sat Jul 25, 2020 2:19 pm**

maxpower wrote: ↑Sat Jul 25, 2020 2:05 pm Did you check for that "Game motion plus" setting? If it is on, you can save another frame of lag by turning it off. It is in the settings under General -> External Device Manager -> Game Mode Settings.

Yeah, I have disabled all of those “advanced” features before doing the lag test.

Posted: **Sun Jul 26, 2020 9:28 pm**

bootsector wrote: ↑Wed Jul 22, 2020 9:16 pm It's me again on this one-man-thread

So I've plugged in a PC on my TV and indeed it supports 1440p:

The issue seems to be the horizontal resolution: The TV seems to support 2560 but not 1920.

Since MiSTer doesn't seem to support 2560 I can then say that it won't be possible to use MiSTer on this TV.

A few weeks ago, I actually tried a resolution of 2560x1440 on my MiSTer and it worked.

Unfortunately I think there's some sort of hardcoded limit of 2,048 horizontal pixels, though, because the left side of the screen gets all messed up. But it's only a problem when the displayed content is widescreen (e.g. the menu core or the GBA core). And in the case of GBA, setting pixel perfect vertical scaling in the INI fixes that. Another problem is that shaders (e.g. scanlines) don't work correctly.

But it looks amazing on my monitor and it works flawlessly for my purposes, so I highly recommend trying it still.

Edit: Here's the settings I used:

Code: Select all

video_mode=2560,48,32,80,1440,3,5,33,241699

Here it is on my monitor:

: 20200726_173321.jpg (5.69 MiB) Viewed 7828 times

Posted: **Sun Jul 26, 2020 10:22 pm**

@vibes

I'm surprised that it works with such ludicrous over-clocking. You can try to reduce frequency by reducing blanking times, or switch to 50Hz.

If you have Quartus installed, you can recompile the cores, adding in sys/sys_top.v :
after :

Code: Select all

.RAMBASE(32,'h20000000),

add the line :

Code: Select all

.OHRES(4096),

And there will be no clipping.

Posted: **Mon Jul 27, 2020 9:50 am**

Grabulosaure wrote: ↑Sun Jul 26, 2020 10:22 pm @vibes

I'm surprised that it works with such ludicrous over-clocking. You can try to reduce frequency by reducing blanking times, or switch to 50Hz.

If you have Quartus installed, you can recompile the cores, adding in sys/sys_top.v :
after :
Code: Select all
.RAMBASE(32,'h20000000),
add the line :
Code: Select all
.OHRES(4096),
And there will be no clipping.

Do you have a video_mode string with reduced blanking times so I can test it? I didn’t want to force anything on the FPGA by overclocking it. Thanks!

Posted: **Mon Jul 27, 2020 10:38 am**

@bootsector
My own experience is that each screen behaves differently.

video_mode=hp,ha,hb,hc,vp,va,vb,vc,vd,freq

Vertical frequency is freq / (hp+ha+hb+hc) / (vp+va+vb+vc) : 60Hz or 50Hz.
hp and vp are the desired resolution.
ha, hb, hc, va, vb, vc are the sycnhro position and duration. It can sometimes be reduced in order to reduce freq.

Posted: **Wed Jul 29, 2020 9:14 pm**

Grabulosaure wrote: ↑Sun Jul 26, 2020 10:22 pm @vibes

I'm surprised that it works with such ludicrous over-clocking. You can try to reduce frequency by reducing blanking times, or switch to 50Hz.

If you have Quartus installed, you can recompile the cores, adding in sys/sys_top.v :
after :
Code: Select all
.RAMBASE(32,'h20000000),
add the line :
Code: Select all
.OHRES(4096),
And there will be no clipping.

Thanks for the info! The 2048 pixel limit is mostly a non-issue, but running scripts are nearly unreadable so I might end up modifying the Main (?) core.

Regarding the frequency, I realized I'm probably lucky to pull off 2560x1440, it took lots of trial and error, and Googling for others' settings. But do you think it's imperative or worthwhile for me to reduce frequency, e.g. for the sake of the hardware? I run my cores at original Hz (vsync_adjust=2) and most games I play are US or JP, so 50 Hz isn't an option for me. But I wouldn't mind dropping resolution back to 720p if there's a good reason to.

Posted: **Wed Jul 29, 2020 9:21 pm**

vibes wrote: ↑Wed Jul 29, 2020 9:14 pm Thanks for the info! The 2048 pixel limit is mostly a non-issue, but running scripts are nearly unreadable so I might end up modifying the Main (?) core.

linux frame buffer magnification is an option in ini.
try fb_size=2

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MiSTer on a Samsung Q80T at 1440p?

MiSTer on a Samsung Q80T at 1440p?

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