Dumb question guys, is RGB the same as Component?

D

Droog

Well-known member
Hey all!

This is a pretty basic question it seems, but I think my understanding is incorrect.

I am trying to feed a component signal into an RGB input and I am getting nothing. Is there a difference between the two? I guess I never really thought about it, because on most monitors and decks the three BNC's are used for both and you select your input. I was always under the impression that they were basically two different terms for the same thing. This paticual monitor is RGB only, and the camera is outputing component only, I think I am screwed. Guess I'll go Composite.

Does this sound right? Would someboy please shed some light for me?

Thanks a lot!
 
They are a little (but critically) different...

RGB = Red, Green, and Blue color intensity channels.

Component = Y (Brightness [a black & white video signal]), Cr (Red color information), and Cb (Blue color information)

RGB is just the 3 primary color signals. The Raw color signals.

Componenet is a black and white signal with color information for red and blue. The color information for green is calculated from the other signals.

- Mikko
 
Yeah, makes total sense now, and of course as soon as I switched out the monitor to one with Component all was well.

Here is a question; like you said, the two are similiar and yet critically different, why is it that Component is better? It is better right? That is my understanding. It kind of seems like just a different way to do the same thing.

Thanks!

Oh, one more thing. The component signal was coming from a Canon XH A1, you know the little multi pin to 3 RCA's. Well the RCA's are colored, Red, Green and Blue. Is that not a little decieving? Common too, most component stuff that I see is colored RGB.
 
RGB is "better" as it's the original raw native data.

However Component is backwards compatible with Black & White TV - so it's the native system in the TV world.

The broadcast video signal - which is essentially "composite" was originally just a single Black & White video signal - called "Y" (As it's intensity is graphed on the Y axis, with "X" beeing time. This is called a Waveform monitor.)

When color TV came along, there was a choice to either broadcast a black & white AND a color broadcast, or just make a color system that worked with the B&W system too. The choice is obvious. So "Y" remained untouched.

The trick was how to add color? Well some very smart engineer figured out that if you allready had the brightness of the image, you could convay JUST the amount of blue and red in the image, and anything left had to be green. The result is compoent video:
Y - The Brightness of the image
B-Y (Cb) - The blue signal, with Y subtracted
R-Y (Cr) - The red signal, with Y subtracted

As a result; at any point in time the green data is calculated as follows: G=Y+(B-Y)+(R-Y) - The sum of all the signals.

The B-Y signal is refered to as Cb, Pb or in europe, simply "U"
and the R-Y signal is refered to as Cr, Pr or in europe, simply "V"

The "U" and the "V" refer to their axis on a "graph of color", or rather; a Vectorscope.


The color channels are then modulated onto a subcarrier withtin the Y signal in composite video and for broadcast.
A B&W TV will just ignore the color channels and display the Y signal properly.


So thoguh RGB is higer quality, Component is better suited to TV production.


I agree that the use of Red, Green and Blue connectors for component video is misleading. They should be reserved for RGB signals. In europe we actually often use RGB within a "SCART" cable between consumer devices, but there's no need for color codes there.
I Think a much more suitable color code for component connectors would be: Gray (Y), Light Blue (Cb) and Pink (Cr), but alas, it's too late now.

There is a clue to the signal type by the connector (in adition to the obvious lable!)... The order.
RGB generally always has the connectors in that order: Red, Green, Blue
Component generally always has the connector differently: Green (Y), Blue (Cb), Red (Cr) The red is on the other side.

- Mikko
 
Huh... very interesting.

Thanks Mikko:dankk2:

That was my "learn something new every day" tid bit of info:beer:

-brown
 
Rush said:
Dang that sure wasn't a dumb question. :) Thanks Mikko.
Click to expand...

Woohoo! I asked a good question. I deserve a badge:laugh: Whats cool is that I know that somewhere down the line knowing this is going to make me look good, and looking good is what get gigs!
 
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