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aliexpress, are you ok? and if this is actually a thing, who tf has digital vga!?

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@ln

I think this works the other way around 🙂 HDMI can additionally carry an analog signal.

@fribbledom nope, it's advertised vga->hdmi. also hdmi doesn't do any analog either afaik. the only thing that worked painlessly was dvi->hdmi because dvi supports analog and digital.

@ln@chaos.social @fribbledom@mastodon.social well, strictly.. DVI-D is HDMI, just without some of the between-frame signalling HDMI permits while vblank happens in the video signal

@ln

Interesting, I have been using passive HDMI->VGA cables on various systems (>10 years ago).

So much misinformation out there, which also breaks with another thing I've been taught years ago: DVI and HDMI carry the exact same signal and feature the same 29 pins, just in a different form-factor. Apparently not true?

I'm confused now 😆

@fribbledom yep, that's not true. dvi has lots more pins (en.wikipedia.org/wiki/Digital_) and hdmi also has features like an audio return channel or ethernet over hdmi (en.wikipedia.org/wiki/HDMI).

the pinouts are really nice on wikipedia :3 also i never knew just how many dvi variants there were!

@ln

Interesting, apparently the 29-pin HDMI would have been HDMI Type B, which never made it to the market.

Another oddity: Wikipedia claims DVI can't carry audio signals, but my old 27" DVI monitor here does exactly that as we speak 🤔

@ln

Oh my:

"Although DVI was not designed for audio, some graphics card manufacturers created a way to bypass the restrictions, so they can carry over video and audio signals. We’ll run through the exact steps needed to carry over DVI audio in the next section."

bluecinetech.co.uk/does-dvi-ca

@fribbledom @ln I like this quote a few paragraphs in: "The first two versions (DVI-I and DVI-A) use analog signals, which most modern GPUS are not compatible with"

Considering that DVI stands for Digital Visual Interface, I have to wonder what analog signals are doing there in the first place. 🤔

@ln I wonder if you could use the SERDES as a DAC like a Delta Sigma modulator.

@uint8_t @ln Hm, though that already uses a DAC chip instead of using a SERDES to make low-frequency analog signals... It won't work on a usual device, you'd need an FPGA for that, but then it should be possible to make a HDMI / VGA combo port by using the HDMI signals as analog signals. If you have 5 GS/s at 1 bit, you could get like I think 100 MHz at 6 bits?

@x44203 yeah it should work in theory with a low pass filter

@x44203 hmm, maybe? there's lots of really cheap ways to produce vga output.

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