I seem to remember some HDMI flag you can set to tell the display which aspect ratio to use. Don't know if the OSSC has this implemented but it may be worth looking into

Maybe your 1200p LCD would respect the value of the aspect ratio flag if it was set and the thing was in "preserve aspect" mode

maxtherabbit wrote on 2020-06-09, 14:54:

I seem to remember some HDMI flag you can set to tell the display which aspect ratio to use. Don't know if the OSSC has this implemented but it may be worth looking into

Maybe your 1200p LCD would respect the value of the aspect ratio flag if it was set and the thing was in "preserve aspect" mode

That would be cool. It does not seem too documented though .

What I have seen so far looks more like automatic ratio switching based on either horizontal/vertical pixel ratios or maybe simple content/image analysis, maybe both .

Even if this is some form of WSS, it is probably optional. Good luck get info out of Acer (or any other manufacturer) as to whether they support it .

Just scratched another one off my list of potentially interesting flatscreens for retro gaming, the Eizo S2000.

Got a used one through a local classifieds ad. The monitor itself is a 20" model with a resolution of 1600x1200. It will accept 70 hz mode over DVI, but the panel seems to be driven with 60hz still, resulting in visible tearing and frame drops. Commander Keen 5 is a great game to test this reliably. This is always a dead giveaway for this kind of thing. 70hz over analog VGA also results in the same tearing. Some monitors can do at least proper 70hz over VGA - not this one. The culprit probably is an internal framebuffer of the monitor, which would also explain the 16ms of input lag (tested with Leo Bodnar tester).

Of course, as has been discussed in this thread, VGA entails the ever-prevalent quantization error (non-uniform pixel width every other few columns) for 720x400, which is btw NOT a scaling artifact and is also observed with this model.

My other Eizo S1911 (around the same manuf. date) will accept 70Hz over DVI just fine without any tearing, but obviously it's not ideal for retro gaming because it's a 19" model with a 5:4 aspect ratio - never the less, it's a proof that smooth 70hz over DVI is technically achievable and some capable devices do exist.

Keep in mind, that there are not many video cards that will actually output real 720x400@70 hz or 640x400@70 hz over DVI. The Voodoo5 MAC (Voodoomac) which I used for testing does this reliably. Other cards will behave differently, also determined by what is stored in the monitor's EDID. The Voodoo5 (MAC) doesn't seem to care about the EDID.

Verdict: The monitor might be OK-ish for some 60 hz gaming, but there are better alternatives with lower input lag like the HP L2035 (~7ms).

The search continues... few models remain:

• LG Flatron 2010T
• NEC MultiSync 2080UXi(-BK)
• NEC MultiSync 2090
• Iiyama ProLite E511S (-W/B)
• Lenovo ThinkVision L201p
• Eizo FlexScan S2133
• NEC MultiSync P212

Chris

PS: If I come across a Trinitron CRT in great condition I might just give up the search. 😀

Locutus wrote on 2020-11-30, 17:35:

Just scratched another one off my list of potentially interesting flatscreens for retro gaming, the Eizo S2000. […]
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Just scratched another one off my list of potentially interesting flatscreens for retro gaming, the Eizo S2000.

Got a used one through a local classifieds ad. The monitor itself is a 20" model with a resolution of 1600x1200. It will accept 70 hz mode over DVI, but the panel seems to be driven with 60hz still, resulting in visible tearing and frame drops. Commander Keen 5 is a great game to test this reliably. This is always a dead giveaway for this kind of thing. 70hz over analog VGA also results in the same tearing. Some monitors can do at least proper 70hz over VGA - not this one. The culprit probably is an internal framebuffer of the monitor, which would also explain the 16ms of input lag (tested with Leo Bodnar tester).

Of course, as has been discussed in this thread, VGA entails the ever-prevalent quantization error (non-uniform pixel width every other few columns) for 720x400, which is btw NOT a scaling artifact and is also observed with this model.

My other Eizo S1911 (around the same manuf. date) will accept 70Hz over DVI just fine without any tearing, but obviously it's not ideal for retro gaming because it's a 19" model with a 5:4 aspect ratio - never the less, it's a proof that smooth 70hz over DVI is technically achievable and some capable devices do exist.

Keep in mind, that there are not many video cards that will actually output real 720x400@70 hz or 640x400@70 hz over DVI. The Voodoo5 MAC (Voodoomac) which I used for testing does this reliably. Other cards will behave differently, also determined by what is stored in the monitor's EDID. The Voodoo5 (MAC) doesn't seem to care about the EDID.

Verdict: The monitor might be OK-ish for some 60 hz gaming, but there are better alternatives with lower input lag like the HP L2035 (~7ms).

The search continues... few models remain:

• LG Flatron 2010T
• NEC MultiSync 2080UXi(-BK)
• NEC MultiSync 2090
• Iiyama ProLite E511S (-W/B)
• Lenovo ThinkVision L201p
• Eizo FlexScan S2133
• NEC MultiSync P212

Chris

PS: If I come across a Trinitron CRT in great condition I might just give up the search. 😀

If you can live with a 1920x1200 monitor , you could consider the Philips 252B9, which has an explicit 4:3 mode and handles 70Hz input and output. Combined with an OSSC and an HDMI switch, it is my current solution .

Thanks for pointing that out. In my experience, Philips monitors are notoriously known for input lag. Do you have some means of measuring the lag on your model?

If input lag concerns you the most, I'm using an AOC G2590PX which goes up to 144 Hz (120 Hz on the HDMI input) and has two 4:3 and one 1:1 option. Unfortunately it is 1080p so you won't get the perfect scaling a 1920x1200 LCD would provide for 320x200 games. However I recall darry tested the 252B9 with vsynctester and found no issue with lag, including most importantly at 70 Hz.

I find the 1:1 option very nice for 640x480 games since OSSC provides a line doubling mode, so you get a pixel-perfect 1280x960. See Re: Widescreen monitors and 4:3 aspect ratio compatibility thread

Tested a Dell UltraSharp 2007FPb (don't know which panel IPS or VA) from 2009 today. It's a nice monitor with a good image, S-Video in which is an uncommon connector. Input lag is very low at ~3ms which is insanely good. Sadly, no 70hz support (neither DVI nor VGA).

Pretty good monitor for high-end 4:3 Win98/XP retro-gaming at 60Hz, though. Probably gonna keep it for that.

Chris

Locutus wrote on 2020-12-07, 15:05:

Tested a Dell UltraSharp 2007FPb (don't know which panel IPS or VA) from 2009 today. It's a nice monitor with a good image, S-Video in which is an uncommon connector. Input lag is very low at ~3ms which is insanely good. Sadly, no 70hz support (neither DVI nor VGA).

Pretty good monitor for high-end 4:3 Win98/XP retro-gaming at 60Hz, though. Probably gonna keep it for that.

Chris

How does it do with dos games? Been looking at this model instead of a CRT.

Since most DOS games use a 70 Hz timing, this monitor is not very well suited to play them. It will display legacy modes such as EGA, VGA, etc. but only with tearing and dropped frames, as the panel is natively driven at 60 Hz. As usual when using analog input (VGA) on TFTs, the quantization error that is discussed at the beginning of this thread can be observed. At this time I cannot recommend any TFT for DOS gaming.

I totally agree with you Locutus that CRTs are the best for DOS gaming.

Nonetheless CRTs are difficult to find and not always practical. In these situations the OSSC plus a monitor that has a 4:3 option and is 70 Hz capable on the HDMI input is a decent alternative:
- no quantization error (with OSSC sampling at 640x400p)
- no dropped frames
- 4:3 aspect ratio preserved.

This also solves the issue of modern LCDs no longer having a VGA input.

elianda wrote on 2020-06-09, 09:16:

I have not found a TFT with VGA input yet where 720 and 640 pixel sampling can be set.

I am not sure about that, but my L367 can be set to "Textmode" which leads to 720x400 and "Graphic" which leads to 640x480.

dr.zeissler wrote on 2020-12-08, 07:35:

elianda wrote on 2020-06-09, 09:16:

I have not found a TFT with VGA input yet where 720 and 640 pixel sampling can be set.

I am not sure about that, but my L367 can be set to "Textmode" which leads to 720x400 and "Graphic" which leads to 640x480.

The expecting setting should be between 720x400 (VGA text mode) versus 640x400 (320x200 in mode 13h which is line-doubled by all VGA cards on analogue RGB output), so maybe you are referring to something different .

Additionally, having consulted the html version of the Eizo L367 manual, I was unable to find a reference to this. Do you have a reference explaining this function that you can attach or link to ?

The L367 has 70hz support in 720x400...but I'll have to check this setting (Text/Graphic-Mode)

"Others -> VGA Selection" let's you choose between VGA-Text/Graphic.

you are pretty stuck in a dilemma, because old TFT's that are not widescreen often do not have a superbe image-quality, but suffer from slow timings (25ms+) which is bad on scrolling/moving objects. I did lot's of testing and no 19"+ delivered what I wanted, so I always use:

- L367 (PC/DOS/Mac) (50hz capable via vga in 800x600 used in dosversion of css64)
- 51vm Amiga/Atari (full 15/50 capable) same model als 71vm but only 15"
- 71vm Amiga/Atari (full 15/50 capable) prefered on scandoubler 31.5/50 because 720x575 has no missing pixels on amiga 320x256/640x256/512 etc.), without scandoubler resolution is 640x240 so 16pixels missing. Interlace is also perfect when using scandoubler.
- 1550m Amiga/Atari (full 15/50 capable) screen is a bit blurry but colors are NICE!

Doc

dr.zeissler wrote on 2020-12-08, 10:46:

The L367 has 70hz support in 720x400...but I'll have to check this setting (Text/Graphic-Mode)

"Others -> VGA Selection" let's you choose between VGA-Text/Graphic.

Thank you .
I believe that I understand what you are implying, but I disagree with your interpretation .

The screenshot lists supported input resolutions and the Remarks column details what they are typically used for. IMHO, this does not imply that 320x200 (always output as 640x400 over analog RGB because line-doubled by the VGA card) is sampled differently than 720x400 by the monitor .

Additionally, I cannot find anything in the manual the would let one manually set the monitor to the values mentioned in the Remarks columns ("VGA Graphics" for 320x200 and "VGA TEXT" for 720x400). The only thing I do see is "Selectable FineContrast ", which lets you chose between Custom, SRGB, Text, Picture, Movie (which do not correlate with what is written in the Remarks column), but these are just color/contrast presets that practically all monitors have in some form or other. I have never seen those change input sampling rate on any monitor .

However, in this manual https://www.eizoglobal.com/support/db/files/m … lexScanL367.zip which I have also attached here .

720x400 and 640x400 are (obviously shown) as having different dot clocks :

That this somehow implies that the monitor can somehow distinguish between the 2 modes and adjust sampling rate accordingly is highly unlikely, IMHO .

The only way to be sure is to test it . A great first test would be a photo or external capture of the right side of the Doom HUD .

I suppose that by oversampling by, let's say 4x a monitor could in theory distinguish between the pixel edges, count them and switch between 640 and 720 pixels (as long as you have a straight line of non-black pixels.) Presumably something similar happens when you press the Auto-config button to align the sampling with the pixel center. However I kinda doubt this was ever implemented since it would be rather complex and the demand was very small.

cde wrote on 2020-12-08, 20:28:

I suppose that by oversampling by, let's say 4x a monitor could in theory distinguish between the pixel edges, count them and switch between 640 and 720 pixels (as long as you have a straight line of non-black pixels.) Presumably something similar happens when you press the Auto-config button to align the sampling with the pixel center. However I kinda doubt this was ever implemented since it would be rather complex and the demand was very small.

Repurposing a contrast detection auto-focusing algorithm from the camera world might be an option . I suggested something like that for OSSC Pro . Hopefully, the idea is not too ridiculous .

Another simpler, but more bandwidth intensive (and thus out of scope for OSSC Pro) , way to do it would be to, upon detection of one of the 2 ambiguous resolutions, switch horizontal sampling to the lowest common multiplier of 720 (900 total pixels) and 320 (since this is actually line doubled to 640 with 800 total pixels, using a value of 400 for total pixels should work, I think) , which is 2880 3600 (taking into account all pixels, not just active ones), then decimate the resulting sample to both 720 and 320 and finally determine which of the two decimated results, when re-multiplied to get 2880 3600 (taking into account all pixels, not just active ones), is identical to to the original sample . This could be implemented on a line-by line basis for minimal latency and a bit of de-bouncing logic to avoid unnecessary switching . Again, apologies if this makes no sense, I am not an expert in image processing or the related math .

EDIT : Actually, corrected values for actual complete lines, not just active pixels . Considering that 640x400 is line doubled anyway, if assume it should be possible to use 400 as a theoretically sufficient sampling value for arriving at the lowest common multiple sample rate of 3600 (for 900 and 400), otherwise the needed sampling rate would be 7200 (for 900 and 800).