DOS ain't dead

Hi,
I was a bit looking through portfolio of modern 4k LCD panels (I'd like to buy one in future) and found that almost none have old good analog VGA DSUB-15 input that would allow me connect an old PCs without a need having another LCD on the table. Of course I don't want pull 4k from old VGA I just need to display it some way, if possible with some choices of 1:1 and integer scaling/full scale with preserved aspect ratio. Does anybody use some kind of convertor - what are your experiences?
I found one:
http://www.alza.cz/vention-vga-to-hdmi-converter-w...cro-usb-and-audio-port-0-15m-black-d5827559.htm
But one user told me that it doesn't work smoothly, some resolutions results to black screen on attached panel...

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DOS gives me freedom to unlimited HW access.

Hi,

I have a virtualboy with a VGA mod and I'm using this to convert to HDMI:

https://sewelldirect.com/products/luna-bnc-to-vga-hdmi-converter?_pos=2&_sid=2670972a7&_ss=r

I've used this one with TVs, LCD monitors, and KVM switches. Seems like a design produced and branded by many. You can find many similar devices on Amazon, eBay or AliExpress. They usually cost somewhere near $10 USD.


https://smile.amazon.com/gp/product/B07F1K3QQX/

> Does anybody use some kind of convertor - what are your experiences?

You have a problem: Low resolution support (like 320*20, 640*400, 640*480).
So, does not expect success from cheap converter.

They works good in high resolution (like hd) - they just make copy image from source to dest WITHOUT any scale. So, if modern TV/monitor does not support low resolution (99.99% cases) this converter is fail.

So, try it (i dont use alza very long time, but imho alza must provide order returns and m0neyback), but possible you see black screen and need normal upscaler, which can convert (rerender) 320*200/640*400 to 1280*720 (minimum).

May be you find something work. (will be interesting to see).
New-made devices (upscaler) have cost ~$200.
Also, check video/TV-studio hardware - you can pickup on ebay used converters. (check Vogons forum for models)

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Make DOS great again!

Carthago delenda est, Ceterum censeo Carthaginem delendam esse.

Yes I guess there's some catch... HDMI itself should support at minimum resolution 640x480 with at least 25MHz pixel clock. To output lower resolutions it would need set some double-scan or high refresh rate to increase pixel clock above 25MHz. I don't expect a cheap adapter would contain a scaler engine, it just digitize analog input and encode to TDMS and serialize out. So probably some smarter box would be needed. I know about OSSC project but it use some quite expansive FPGA chip, it's aimed on lower resolutions but I didn't find its maximum resolution.

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DOS gives me freedom to unlimited HW access.

> Hi,
>
> I have a virtualboy with a VGA mod and I'm using this to convert to HDMI:
>
> https://sewelldirect.com/products/luna-bnc-to-vga-hdmi-converter?_pos=2&_sid=2670972a7&_ss=r

does it really convert VGA input to HDMI? Not just a VGA passthrough?

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DOS gives me freedom to unlimited HW access.

> YHDMI itself should support at minimum
> resolution 640x480 with at least 25MHz pixel clock. To output lower
> resolutions it would need set some double-scan or high refresh rate to
> increase pixel clock above 25MHz.

Yes.

1. Frame rate. This is more relevant topic for commodore/amiga - they generate 15 frames per second. May be CGA also have this problem. But low possibility - VGA.

2. Image resolution.

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Make DOS great again!

Carthago delenda est, Ceterum censeo Carthaginem delendam esse.

I'm thinking about making own converter. Maybe I could utilize an old LCD monitor controller board with VGA + DVI input and LVDS panel output and attach it to custom board with LVDS to HDMI converter, maybe IT6263 chip could do this (cheap on ebay), just thinking...
This should ensure that all input resolutions an old LCD accepts will be processed (including scaling) and passed to HDMI (fot the VGA it will pretend it is still real LCD monitor), so it should work better than cheap adapters and costs less than FPGA chip.

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DOS gives me freedom to unlimited HW access.

> > Hi,
> >
> > I have a virtualboy with a VGA mod and I'm using this to convert to
> HDMI:
> >
> >
> https://sewelldirect.com/products/luna-bnc-to-vga-hdmi-converter?_pos=2&_sid=2670972a7&_ss=r
>
> does it really convert VGA input to HDMI? Not just a VGA passthrough?

It's seem to be a passthrough but not sure.

Before it, I test 2 others items:
https://www.amazon.fr/gp/product/B01IHTPI9S/
https://www.amazon.fr/gp/product/B072NCTBVP

Booth give me problem, old samsung LCD (unsupported mode error) and 2018 LG OLED (black screen with nothing).

I'm using a Ligawo VGA->HDMI converter with my capture card and it works very well:
https://smile.amazon.de/gp/product/B00IJBOMN8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Before that I used a cheapo converter which blanked out on a lot of resolutions:
https://smile.amazon.de/gp/product/B072KR7MJW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

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OK, thanks for tips, I'll try something my way, will be updated in thread
https://www.vogons.org/viewtopic.php?f=63&t=86206
also other users contributed with some tips and photos.

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DOS gives me freedom to unlimited HW access.

I just bought a cheap VGA2HDMI adapter on a flea market, just bacuase it was only 2e, didn't expected too much about it so not much disappointed (textmode doesn't work as I expected)
http://rayer.g6.cz/hardware/vga2hdmi.htm#GANA_VGA2HDMI_MINI

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DOS gives me freedom to unlimited HW access.