weedeewee wrote on 2022-05-26, 16:00:

since HDMI = digital, and VGA = analog and there's more differences wrt the actual signals, HDMI can NOT produce VGA signals One […]
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GigAHerZ wrote on 2022-05-26, 13:37:

If i'm reading that correctly, it's not vga-hdmi, but hdmi-vga. HDMI is the source, VGA is the output. AFAIK, HDMI can produce VGA signals. It does not work the other way around.

since HDMI = digital, and VGA = analog and there's more differences wrt the actual signals,
HDMI can NOT produce VGA signals
One should however be able to get VGA resolutions on HDMI, as in 640x480@70Hz, Though, support for displaying these will depend on the monitor or adapters being used.

To hook up an analog VGA monitor to a HDMI output of a graphics card you will always need an active adapter.

I'm aware of the protocol and the fact that HDMI protocol is digital, while VGA is really isn't.
My comment was about HDMI as a port. AFAIK, it can switch over and produce VGA signal. From usage perspective, similar to DVI (port), which has even separate physical pins for VGA signal.

But my memory might be spotty on that part, so...

GigAHerZ wrote on 2022-05-26, 18:01:

AFAIK, it can switch over and produce VGA signal

pretty sure that's not real

GigAHerZ wrote on 2022-05-26, 18:01:

My comment was about HDMI as a port. AFAIK, it can switch over and produce VGA signal. From usage perspective, similar to DVI (port), which has even separate physical pins for VGA signal.

That's the thing. DVI ports (some) have separate physical pins for analog signals. HDMI ports do not. That is not part of the standard.

Kordanor wrote on 2022-05-25, 16:14:

Now I was thinking...AGP existed till around ~2006. And HDMI was starting popping up in 2006 as well with the X1600 Pro HDMI.
Now my question is, whether any of you explored that avenue already and tried that on an old machine running DOS 6.22. Would be interesting to know whether this card works at all and you get some output over HDMI.
Or is there any barrier which makes that impossible? Like requiring a AGP spec to run at all or something else (afaik this just reduces speed, which shouldnt be relevant for DOS 6.22 games).

Well, there are many AGP GeForce 5200, 5600 and 6200 that have a DVI connector. And from DVI to HDMI you just need a passive cable.
However, you won't have a sound output over HDMI.

DVI-D ports actually do carry digital sound, when configured to do so with the otherwise unused pins, so you can get digital audio from a DVI-HDMI adapter or cable.

RetroGamer4Ever wrote on 2022-05-26, 22:52:

DVI-D ports actually do carry digital sound, when configured to do so with the otherwise unused pins, so you can get digital audio from a DVI-HDMI adapter or cable.

It is more accurate to say that DVI-D ports can carry digital sound, rather than that they do. A video card with a DVI-D port will not necessarily have digital audio functionality .

Geforce FX cards and Geforce 6200/6600/6800, for example, cannot output digital audio over DVI-D/HDMI .

There are no dedicated audio pins in HDMI or DVI; audio is sent as part of the same TMDS stream. Whether audio is transmitted/received over the port/wire has to do solely with the source/sink being configured to so.

Indeed, the vast majority of devices do not implement audio over DVI, because it was, again, never defined as a mandatory part of the standard as it was for HDMI.

Kordanor wrote on 2022-05-25, 16:14:

Heyho! […]
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Heyho!

I have been ponderng for a while on how to best have an output to HDMI without paying hundreds of euros for converters.

After I stumbled over several issues with my old 486 idea, I referred back to my Pentium 2, running on a PC100 BXcel Board, which features AGP.

Now I was thinking...AGP existed till around ~2006. And HDMI was starting popping up in 2006 as well with the X1600 Pro HDMI.
And I also found a card which goes into AGP and supports HDMI, which is the "HIS HD 4350 iFan Native HDMI 512MB (64bit) DDR3 AGP"

Now my question is, whether any of you explored that avenue already and tried that on an old machine running DOS 6.22. Would be interesting to know whether this card works at all and you get some output over HDMI.
Or is there any barrier which makes that impossible? Like requiring a AGP spec to run at all or something else (afaik this just reduces speed, which shouldnt be relevant for DOS 6.22 games).

DVI/HDMI should work just fine on DOS 6.22 if you can properly see the BIOS POST screen and so on without issues. I personally haven't encountered a card that can't show BIOS POST when using DVI/HDMI or even DP. The VGA BIOS is responsible for displaying POST screen as well as other VGA functions for DOS and others.

AGP Radeon HD 4000 series have built-in HDMI output, but for AGP cards with only DVI, you should be able to get output on a HDMI monitor with a correct DVI/HDMI converter (or cable).

However, my DOS experience with those AGP Radeon HDs (3000/4000 series) was not that satisfactory. Some games had graphical glitches not present on older (nVidia) AGP ones. The VGA BIOS is to blame as newer video cards start breaking VGA functionalities that are no longer relevant on modern OSes.

Also, some special VGA function calls do not work when using only non-VGA connections (on the video card side). There are a select few games that used such calls and would refuse to run if no real VGA connections are present (DVI/HDMI to VGA adapters do not count), and it would be impossible to satisfy if the card doesn't have any VGA output at all.

BTW: I noticed you're considering using a Pentium II board (PC100 BXcel). The AGP slots on that board is 3.3V so you can only insert cards that do have the 3.3V key, which newer AGP cards do not have (including your 4350). To use newer AGP cards you need at least a board with universal slots (usually AGP4X).

I have a GeForce MX440 with a DVI port, and that works fine in DOS. However, when you use the DVI port it forces the Video signal to 60 Hz even if you use “70 Hz” display modes like text mode or 320x200. This is evidenced by scrolling demos either running too slow or stuttering where they shouldn’t. But it works (of course) fine with any HDMI device.

digistorm wrote on 2022-05-28, 07:40:

I have a GeForce MX440 with a DVI port, and that works fine in DOS. However, when you use the DVI port it forces the Video signal to 60 Hz even if you use “70 Hz” display modes like text mode or 320x200. This is evidenced by scrolling demos either running too slow or stuttering where they shouldn’t. But it works (of course) fine with any HDMI device.

That's why I kept using VGA even in the 1080p days.
VGA was very emulator friendly. On Windows XP/7, at least.
Emulators could use 50Hz/../70/72Hz synchronization, if the driver wasn't blocking it.
HDMI, as well as DVI, were never meant to be friendly to tube era equipment or software.
They expect dumb LCD/TFT panels with standard refresh rates.
The irony is, that they aren't. Most LCDs with an additional VGA port have very sophisticated hardware. That even includes Smart TVs and those glossy 16:9 pseudo-PC monitors from Samsung. 😉

Jo22 wrote on 2022-05-28, 18:28:

That's why I kept using VGA even in the 1080p days. VGA was very emulator friendly. On Windows XP/7, at least. Emulators could u […]
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digistorm wrote on 2022-05-28, 07:40:

I have a GeForce MX440 with a DVI port, and that works fine in DOS. However, when you use the DVI port it forces the Video signal to 60 Hz even if you use “70 Hz” display modes like text mode or 320x200. This is evidenced by scrolling demos either running too slow or stuttering where they shouldn’t. But it works (of course) fine with any HDMI device.

That's why I kept using VGA even in the 1080p days.
VGA was very emulator friendly. On Windows XP/7, at least.
Emulators could use 50Hz/../70/72Hz synchronization, if the driver wasn't blocking it.
HDMI, as well as DVI, were never meant to be friendly to tube era equipment or software.
They expect dumb LCD/TFT panels with standard refresh rates.
The irony is, that they aren't. Most LCDs with an additional VGA port have very sophisticated hardware. That even includes Smart TVs and those glossy 16:9 pseudo-PC monitors from Samsung. 😉

There are LCDs that supports variable refresh rate thru DisplayPort on modern computers as recent video cards lacks analog output. 😉

Gmlb256 wrote on 2022-05-28, 21:04:

There are LCDs that supports variable refresh rate thru DisplayPort on modern computers as recent video cards lacks analog output. 😉

Absolutely! I like DP, because of the mechanical locking on the plug, among other things.
But it seems to be a niche still. At least when it comes to consumer hardware.
VGA can be found more often, by comparison. (And VGA is DRM-free.)
But there's hope. Version 2 was released 3 years ago in 2019, so it's still being worked on. 🙂👍

Some technologies like G-Sync, FeeeSync try to provide flexible refresh rates, also.
But they're highly proprietary and not well supported.

Jo22 wrote on 2022-05-29, 06:20:

Absolutely! I like DP, because of the mechanical locking on the plug, among other things.
But it seems to be a niche still. At least when it comes to consumer hardware.
VGA can be found more often, by comparison. (And VGA is DRM-free.)

Depending on the age of the hardware, and I guess, partially on its class.

On modern LCDs of FullHD or high resolution, DisplayPort has already surpassed VGA. Same with modern GPUs. Partly it is because VGA becomes dramatically less usable as resolution increases.

I just use a radeon 7500 pci with a dvi to hdmi adapter.

Plays dos just fine.