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Discussion Starter #1
Greetings,


Okay, here's the deal. I have a Sharp 9000 DLP on order. I have several components I want to connect, and I may include a Faroudja NRS in the mix.


I need to order a snake to connect the projector to the A/V equipment, and I'd (obviously) like to receive said cable before the projector arrives.


The problem is, I'm baffled as to which kind of cable to order!


There are "component/RGB" inputs on the Sharp (according to a manual PDF I've seen) labeled as follows:


Y(G/Gsync)

Pb(B)

Pr(R)

(HD/Csync)

(VD)


Of course, there's also an S-Video and a composite video connector, and there's a computer RGB (D-sub 15) connector as well.


To this device, I wish to connect:

A Mac (via the computer RGB)

Standard NTSC sources (via S, if NRS not used)

One or more HDTV sources (satellite, XBOX, maybe NRS)

Component (interlaced) DVD player (if NRS not used)


So, computer and NTSC are easy.


What's not clear is how to hook up the HDTV sources and possibly the NRS.


The NRS appears to be labeled on its outputs for BOTH RGBHV and Y/Pr/Pb (I assume it's switchable), and I think the Dish 6000 also supports both RGB (on a computer-style connector) and 3-cable Y/Pr/Pb. I have no idea what XBOX will include. If I get the NRS, then the DVD player will be fed through it. Otherwise, I would probably feed either component 480i to the projector, or upgrade the player and feed component 480p to the projector.


Is either RGBHV or Y/Pr/Pb preferable in some way? Is either of them easier to switch for multiple sources? Should I just buy a 5-conductor snake for future-proof insurance (it's like $40 more than 3-conductor)?


Please help! Thanks!
 

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in order to send HD you will need rgbhv (5 wire); i would connect the NR to the projector using trhe rgbhv setting; then both scaled output and HD will get there. if you want to cover the bases, in case you don't end up with the NR, feed a 5-wire bnc cable, an s-video cable and an rgb/vga cable. You can always just use three of the five wires if you have component, you can use the vga for HD or computer.


it's never cheap
 

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Discussion Starter #3
Thanks for the info! Unfortunately, now I'm even more confused. Aren't there HD components (my Dish 6000) that do "HD Component" video -- HD over 3-wire? Or are those only for 480p?


Thanks again!
 

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The only way the Sharp will accept the signal from the NRS is to go through the RGBHV RCA connectors. Unfortunately, this is also the same connector used for component. If your HD receiver only outputs component, you will have to get a component to RGBHV transcoder and then feed that signal into the passthrough of the Faroudja. That way, you'll have the signal go through the same input.


Thanks!
 

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Discussion Starter #5
Thanks, Jason. I think the receiver can be switched to output either format, so I may be saved. I believe the Sharp also has two component inputs, so I guess I could buy two snakes (probably cheaper than the transcoder).


I will for sure order one 5-wire snake for starters.


Is there a significant signal degradation from using BNC->RCA adapters? The NRS has BNC outputs, but I might order an RCA-equipped snake in case I end up delaying the NRS. Then I could use the snake for component.
 

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First off, a little bit of background on the difference between RGBHV and YPrPb.


YPrPb is always termed component and it is a analog transmission format for video. In most ways it is superior to RGBHV.


RGBHV is better for directly driving the CRT computer monitors. R is the Red portion of the image, Green is the green portion of the image and Blue is the blue portion of the image. H and V are sync lines.


YPrPb is a transcoded version of RGBHV. Y is the lumenance or white portion of the image, Pr is the bi-polar signal for the amount of red in the image, and Pb is the bi-polar signal for the amount of blue in the signal. (In case you are wondering green is generated when Pr and Pb both go negative)


The advantages of component video are:


1. Only three cables are used.


2. Since color is seperated, saturation controls are easy to do.


3. The sync is embedded on the Y channel which helps to ensure better syncronization for the display.


4. RGB can have allignment or progation delays over long distances cable runs. This can cause some smear in white on the screen. Y is inherantly white so this isn't a problem.


The disadvantages can be:


1. White balance isn't always available but most of the time is with component.


2. You can get chroma delays similar to those mention in #4 above but the eye isn't as sensitive to those.


3. Some electronics don't take component like computer monitors.



Now that is squared away a little. Here are my cabling suggestions.


1. Your computer should go to the HD-15 which is RGBHV.


2. You should buy a receiver that has component switching for your component sources. The output of that should go to the component input of your Sharp leaving the HD and VD inputs unconnected.


3. Then run any of your lower quality signals via s-video. (This will also have your on-screen display set-up information for your receiver.


Two 5 coax runs can handle the entire load. One 5-coax bundle would hold the computer signal. The other 5-coax bundle will have three cables for component and 2 cables used for s-video.


Or.....


You can use the NRS for everything. Personally I think the internal scalers on most digital projectors are fantastic and the interlacers are pretty good.


The only reason that I don't write off the NRS is because of the Sharp's current lip sync problem with NTSC sources. If that gets corrected, I would go with my suggestions above.


-Mr. Wigggles
 

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Discussion Starter #7
Mr. Wiggles, thanks VERY much!


Let me see if I understand one thing for certain. When you suggest running my component sources via three of the cables in a 5-cable snake, are those for SD component only? Or HD as well?
 

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Your component input can handle both SD and HD video. The Sharp recognizes the quality of input and uses it appropriately.


They are different signals but when you have them switched through a receiver, it does just that simply switches the input. The reciever doesn't touch the signal and that is why OSD is only on s-video.


-Mr. Wigggles
 

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Here's a related question: I have an accessDTV card that can output HDTV in Y/Pr/Pb form. However, it only has a 15 pin d-shell video out jack on the back (e.g. computer RGB). I have a cable that has a 15 pin d-shell connector at one end, and 5 BNC connectors at the other (R, B, G, Black, Grey). Any idea which 3 of these BNC connectors correspond to the appropriate Y/Pr/Pb inputs on my projector?
 

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Quote:
Originally posted by jamin
Y(G)


Pb(B)


Pr(R)
jamin,


Not quite.


Y = R + G + B


Pb = B - Y


Pr = R - Y



To get RGB from YPbPr:


B = Pb + Y


R = Pr + Y


G = Y - B - R = -Pb - Pr - Y


Greg
 

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Discussion Starter #12
I think the question, though, was about systems like the DVDO that have an HD-15 connector, but you can switch it to output either RGBHV or Y/Pr/Pb on that connector.
 

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as far as the pin-out only goes, jamin is right. that is to say, if YPrPb i being output via the VGA connector, you can identify which cable is connected to which signal line by the color. By the way, grey would be V and black H sync, should you be breaking out rgbhv
 

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Mr Wiggles,


I am installing cabling for a similar setup anticipating a Sharp. (when I can afford it) My question, in your reccomendation doing the component switching does that limit you from calibrating the projector for each source. In other words, say the black levels need one setting for your Progressive Scan DVD and different for your HD source or XBox. Is this a legitimate concern? I'm operating in a vaccum here, because I don't have the equipment yet. If it is a concern, what is the preferred work around? Run enough cables from source --> projector to direct connect into the projectors inputs?


Tanks
 

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Tanks,


Great guestion and we are both waiting for one of the very bright to answer it. You might consider running plastic pipe of the three inch size or so. Leave nylon cord in it. Then you can easily pull through anything that you may need later. This is especially useful with talk of digital connections, good or vile as they may turn out. Art
 
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