Sending component signals through s-video cable

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I am trying to set up a Benq PE7800 projector in our home theater room, and we ran three wires to it - a DVI-D cable, composite and s-video cable.

The DVI cable connects to the DVD player, the composite connects to the VCR, and I planned on having the s-video connect to the computer.

I try it, and the resolution is terrible - my computer was limiting me to only 720x480 (16:9) or 1024x768 (4:3). And 720x480 is way too low.

So, I look on the internet, and try to find out how I can make the resolution go up, when I find out that that is the max for s-video. So, what I want to do is use the 4 wires in the s-video cable for transmission of component video. I already have a VGA to BNC component cable (I don't know why there are 5 wires, but I should only need R,G and B, right?), which I want to find a converter that will let me run it through the s-video cable.

I plan on having it setup this way:

Computer -->VGA to BNC Component cable (already have)--> component to s-video (need) -->s-video cable (already have) -->s-video to component (need) -->Projector.

Does such an adapter exist, and if so, where can I get it?
Perfect! And those work both ways, and they just send the signal through the cable, not convert it to s-video, right?

edit: Looking on infocus' website, at, it appears as if the adapter just turns component into s-video, and is only compatable with 480i signals, while I need higher resolution than that.

is this something I could try building myself? Say I screw up and colors are mixed or something, am I risking damage to the projector or computer, or will the image just be messed up?
Also, what are the different color connectors for on a VGA to BNC cable?

I have a cable just like this

except with only four connectors - a red, green, blue and black one.

I plan on connecting the red, green and blue ones to a component cable and then to the projector, but what is the black and grey connectors do, and are they necesary to get a correct image?


I think I'll just go with standard component through the s-video cable. I've got everything I need except for the s-video couplers, which I can order off the internet for $1 each.

I am able to use the vga to bnc cable to connect from a computer, not just to connect to the vga input on the projector, right?

Just to be sure, component signals share a common ground, right? So I could use 3 of the 4 pins in the s-video cable for R, G and B, and the fourth for ground, right?
nobody knows if it's possible to connect a computer to a component video input ths way? I don't see why not, but I want to make sure.

I tried using just the RGB inputs on my monitor, and disconnecting the v ahd h sync, but those are the connections my monitor uses to turn it on and off, so I couldn't even get the monitor to turn on with just the RGB inputs connected. If I use the component plugs, it's different, right?

Is anything I'm doing risking damage to the projector or computer? I know I asked this already but nobody responded.
scott wurcer said:
You might find my comment in an old thread. Many projectors (my Epson does) support sync on green, so you just need to cut a VGA cable and put three RCA's on it Y-G ; PR-R ; PB-B. R, G, B being the standard monitor RGB pins.

Just looking at the manual for the projector and the connections on the back, those connections are on the projector. In the manual, the section that uses those three BNC connectors with the same names as the ones you said is called "Connecting Progressive Component (DTV Y/Pb/Pr)" Does that sound right?

Either way, the connections are G/Y, B/PB, and R/PR, just like you said.

How can I connect these from a VGA plug?

edit: scott, I found your post about the adapter you made. Did you just connect the R,G,B and all or some of the grounds in the VGA cable? Also, did you do anything about the H-sync or V-sync connectors in the VGA cable? If so, what?

And what resolutions could you get your computer to display at?
OK, maybe I'm a little confused. My projector shares one VGA plug with computer and component video. I had to DIY an RCA (from my DVD) to VGA cable by cutting up an extra VGA cable, there is a ground or multiple ground pins but inside the VGA cable the wires are coax so I just connected them to the ground on the RCA's. No sync connections were used and a smart projector should sync on green if no sync is found (I think).

I don't use my computer with this projector. If you want to take your computers RGB (VGA out) and put it into the component inputs, this won't work. Y, PR, and PB are totally different. The DVD player and projector work together to make the correct aspect ratio, EPSON calls it 'squshed' and 'unsquished' mode. The results are better than I could ever get with my computer especially since the projector is only 800x600. I fact the results surprised me.

I don't fool around much with computer video and I'm not sure of the details but I think the projector has a digital engine expects yPrPb DVD data to optimize things. IIRC the YPrPb outputs pack as much information in as possible ie. no letterboxing. I'm sure there are video cards out there that do YPrPb and all that considering all the videophiles out there.
So, you're saying that if I try to do this without connecting the H and V sync, the highest resolution I can get with it is 480i, which is no better than s-video.

Would I at least get better picture quality than with s-video, or would my rigged setup possibly degrade quality.

Actually, does anybody know if there is such thing as a manual DVI switchbox? I've seen KVM switches with DVI but I don't need anything that fancy. I just want something with a manual switch to switch between DVI on my DVD player and the DVI output from the computer. Since they are digital, I also wouldn't have to worry about that switchbox degrading signal quality.

Or...Thinking again, a DVI cable can carry analog or digital signals. Is there an adapter that would let me use the digital for the dvd player and the analog for the computer?

edit: and thinking once again, I dont think that would work because I bought a DVI-D cable not a DVI-I cable. But just so I know is there an adapter that allows using the cable for two signals?
soundNERD said:
So, you're saying that if I try to do this without connecting the H and V sync, the highest resolution I can get with it is 480i, which is no better than s-video.

Would I at least get better picture quality than with s-video, or

Actually the H sync and V sync wouldn't help. I checked and there are video cards that support native 1024x576 that's what you want. The VGA or DVI output would then be right for your projector. My projector was 800x600 max so something like 480p is the best I can get. I still find it a little confusing that widescreen movies are mostly 2.35:1 or some such not 16:9 and there is still some fudging to do.

BTW you can try the download mentioned here (Powerstrip) to coax all the strange clocking modes out of your video card if the don't show up by default.
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