Techie video stuffs.

[-N-]

I've got an S-Video Y/C signal coming out of my monitor and I want a component video (YPbPr) signal from it. Does anyone know the specifications for signal merging from PbPr to C in downconverting video signal, so I can possibly build a signal separator?

edit: To clarify, I need to decode a single C signal into two difference signals, Pb / Pr.

edit again: I suppose since this is coming out of a computer, it can use RGB and then downconvert to YPbPr. In which case, someone give me specs on RGB encoding and how to downconvert to YPbPr ?

edit some more: Does this look feasible?

[Samuraid]

http://en.wikipedia.org/wiki/YCbCr

[-N-]

edit some more: Does this look feasible?

I think today's lesson is: downconverting is easier.

Thanks for the link Samuraid - first I've seen the constants' values, but still not enough info to actually separate the signals. I found an interesting way to convert from component to RGB using op-amps, though, so maybe that'll work for S-video to component.

[Flying Mullet]

That looks like too much work. You should just go watch a movie.

[Endless]

I'm curious about what you're trying to achieve, though.

[-N-]

I have a TV with two video inputs - one takes either Y/C video or component video, but of course, only one at a time. The other input takes YPbPr input. I don't want to have to constantly unplug my second monitor (via S-video) everytime I want to play my PS2 (on component), so I wanted to convert the RGB signal from the monitor down to YPbPr to put in the other video slot so I could just switch back and forth. But, now I need to build an active filter and do some analog math, because my video card doesn't support YPbPr-out over the 15-pin port, only RGB out. But even so, I should have gotten a green-filtered image, but I didn't, which leads me to think I soldered a connection wrong. :\

[Endless]

Wouldn't it be 100x easier for you to make a simple switch that takes s-video and component in, is plugged in both the s-video and component plugs and depending on the switch's position, only lets the signals go through one of the two at a time?

[-N-]

:o

>_<





Actually, I did a bit of testing - even when the S-Video cable is plugged in and not delivering signal, it overrides the component video in and I don't see the PS2 video (but I hear the audio). :\

[Endless]

Was the s-video cable plugged at both ends or just in the TV?

[-N-]

That happened regardless of where the s-video cable was plugged into on the other end.

[Endless]

That's odd, because if the s-video cable was plugged <i>only</i> in the tv but the other end loose, the tv shouldn't act as if there was a cable at all.

[-N-]

Uh huh. That's what I thought. I think there's a connection between the metal shell of the S-video cable and the receptor, such that even when the cable is connected but off, the TV still senses the presence of the s-video cable and cuts the component video in. I wonder if I wire the pins directly (without the shielding shell) whether or not the same phenomenon will happen. However, I have no idea how I could get that to be any sort of a connection that could last long enough for testing.