Extron HD15 input: Which pin is Composite video?

[emuola]

I'd need to build a custom cable for my VIC-20 (PAL), which basically only outputs composite video. I see there are adapters like this (https://www.extron.com/product/syvgamrgbhvf), but as it takes ages to get those here in Finland, I'd rather build it myself. I know it is really simple to build, once I'd know the correct pin(s).

Would someone have this info based on experience?

[NewSchoolBoxer]

Am I overlooking something? The HD15 adapter you listed separates the R, G, B color lines and Horizontal and Vertical sync into 5 BNC female plugs. It's what we call a BNC breakout cable. It has nothing to do with Composite. RGB is one color space, Component/YUV is another with a matrix math conversion between the two. Composite with S-Video share yet another color space that cannot exist above 480i. You need a video encoder chip to transcode from one color space to another. I'm sure the chip datasheets would show you the pin layouts.

If you're going to a television with Composite, just feed it that unless you're modding the console or something for native RGB. Transcoding to YUV or RGB doesn't turn a low quality signal into a high quality one. Indeed you add some noise to it.

I don't know of any Composite/S-Video to RGB transcoding chips by name but they certainly exist and several different transcode+upscale devices are sold for this purpose. They use common name "VGA" instead of "HD15" that most people haven't heard of. Avoid the half moon shape $15-20 devices because they are hardwired for NTSC by replacing the PAL <-> NTSC toggle switch with an LED light and ironic QC sticker. The StarTech $40-50 device I could have faith in.

[maxtherabbit]

Am I overlooking something?

yes, Extron marketed and sold a composite video dongle that allowed the switchers to pass through composite

it didn't transcode it, just composite in, composite out

[NewSchoolBoxer]

Thanks maxtherabbit, I understand the question now. Wanting to recreate the composite video dongle for pass through since the real thing is hard to come by. Hopefully someone here knows.

If I had an Extron VGA switch and 4 channel oscilloscope, maybe I'd try to brute force it. SCART pin 16 is 0-0.4V logical low for composite and 1-3V logical high for RGB. Best case the pass through indicator is something similar.

[Unseen]

I know it is really simple to build, once I'd know the correct pin(s).

I haven't tested it, but I'm 99% certain that it would work: Just connect the composite signal to the green channel (HD15 pin 2) and make sure Ground is also connected (HD15 pins 5,6,7,10).