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Are component (RGB) cables really necessary? Cheap solution

Last response: in Graphics & Displays
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September 19, 2006 11:58:06 PM

I just bought a TV with RGB inputs and i connected my laptop's video out to it using the RGB outs. But instead of using expensive RGB cables I used the cheapo Red Yellow and White A/V cables expecting them to work. The TV only displays red and black & white. Is this due to the nature of the cables, ie. not their purpose, or is my laptop's out, or the splitter cable bad?
I would think that the cable choice didn't matter, I mean I thought they were just cables.
In case you were wondering why anyone would do this, well, I'm a college student (my 27"TV cost me $50!!!). I'm cheap/broke.
Thank you for your patience.
September 20, 2006 1:25:05 AM

I'm no expert on this, but I do know that composite (the red, yellow, and white) cables will not work with anything dealing with component (the red, green, and blue).

This is the case because composite video only uses one cable, the yellow one, for transmitting video info. The other two cables with it, red and white, are for stereo sound. The three component cables ALL carry video information, so that's probably why you only see one color (I'll throw out a guess and say that you connected the yellow cable to the red input). In short, cables do matter.

I am a little confused though- if your laptop is capable of output in component, is it not also capable of output in S-video as well?
September 20, 2006 1:32:42 AM

when i connect the cables, it doesn't matter which order i arrange them, i always only get red. i am using composite because i thought quality would be greater than s video, as i want the tv to play movies.
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September 23, 2006 6:26:32 PM

I'm going to take a guess and say you got red because the frequency modulation fell close enough in that color to go throught, but that is really really weird. Especially since green gets the most bandwidth.

Maybe I can help you understand the way the cables work.

Composite takes the red, green, and blue signals and mashes them together through modulation. (Green is actually what is left over if you take blue and red out of the black and white. Keep in mind equal amounts of RGB = White)

That is the yellow cable. The white is mono sound. The red is stereo. In the case of stereo sound the red is the right speaker and the white the left.

S-video was created to enchance the appearance of Composite devices when newer (many years ago) VCRs had greater potential for quality.

It combines the signals in a different way to reduce noise and improve quality (mostly the black and white quality which has the most bandwidth anyway.)

Component Video (RGB) is designed to keep the RGB color split to enchance quality. (Not used for sound)

This is usefull for LCD and Plasma TVs since each pixel has its own set of three electrodes (Red, Green, and Blue) to control the color you see.

A CRT just sprays everything out of one tube.

S-video is better than composite, but component is the best.

If the picture isn't that great to begin with (below DVD) it won't matter.


(You're dealing with different quality and time eras of wires so they are different in design even if the shape is the same.)
October 6, 2006 4:36:11 PM

i have a similar question - i wanna connect my computer to my TV (a standard def, 4:3 Sony set), i have a ATI X800XTPE and was wondering which would give me the better picture quality, S-video or composite??
October 6, 2006 5:04:48 PM

its a sony triniton, about 10 years old, but still a good TV, it has composite (yellow, red, white yeah) inputs, as well as scart and s video!
October 6, 2006 5:19:12 PM

oh ok, well im just gettin mixed up with the lingo, ok, so whats the best out of AV and s video?
October 6, 2006 5:52:23 PM

Quote:
Buy the way
RGB=Composit video.

RGB just refures to the color coding of the cable.


no, no, no. that is wrong.

composite video = yellow video out/in that has all the color info in one signal and cannont send a high definition signal
component video = the separate 3 red, green, and blue signals that can send a high definition signal

they are not the same thing.

and to the op, it shouldnt matter what cables you use. you do not have to use certain special "component video cables". they are all a the same thing. just match up the connections properly and you should get an image. seeing how your image is not displaying correctly, i would say there is a problem with a) your connection, b) the component output on your computer, c) the input on your tv.

i have a radeon x1800xl that would display the image but only with a redish purple color. the component output dongle was bad. ati sent me a new one and it is golden.

im not trying to be rude in this post, just trying to clear the waters some.

edit: and just to help http://en.wikipedia.org/wiki/Audio_and_video_connector
October 6, 2006 6:23:29 PM

if i can add in my 2 cents....i did a quick test of component video cables. I got some really expensive ones ($100) and i got some really cheat ones from walmart ($5-$6) and tested them both out on my 1080p monitor using a 1080i signal from my comcast DiscoveryHD channel....i really couldn't tell the difference between the two cables. But i didn't try the a/v cables, lol....maybe i'll go home and try it :D 
October 6, 2006 10:43:27 PM

Dude-$'s do make a difference.I've bought a couple of cables from a $ store anjd one barely worked and one didn't at all,and niether did their exchanges.I found some higher grade RF cables at RadioShack & BBUY and all is well.So yur Mom was right-Yuo get what you pay$'s for!HappyHunting!
October 6, 2006 11:07:37 PM

if you use s-video over composite you will notice a diffrence
October 6, 2006 11:09:57 PM

good awnser
October 6, 2006 11:12:51 PM

composite= yellow= lowest resolution
s-video= better resolution
component= best resolution

except for hdmi and dvi wich are the top connects
and hdmi carries video and audioon one connect
October 6, 2006 11:24:34 PM

the composite cables yellow white and red will not work for
component you will need the actual component cables

also as said before they carry only video signal

i think component cables are around 20$ or less at wal mart radio shack
ect. you dont need high dollar ones.
October 7, 2006 3:32:06 AM

Quote:
good awnser


thank you.


in all honesty, you really dont need special component video cables. you can use normal "a/v" cables to send just the video signal. you then need another set of red/white cables to send the audio. all low end component/av cables are just a copper cable. nothing special about the component cables. i ran my dvd player to my sony set that way for a month until i bought a much nicer ($$) set of component cables.
October 7, 2006 4:26:08 AM

Quote:
good awnser


thank you.


in all honesty, you really dont need special component video cables. you can use normal "a/v" cables to send just the video signal. you then need another set of red/white cables to send the audio. all low end component/av cables are just a copper cable. nothing special about the component cables. i ran my dvd player to my sony set that way for a month until i bought a much nicer ($$) set of component cables.

...and I bet if you were honest you'd say you couldn't tell the difference between the low end cables and the nicer set just from the picture quality, rightt?
October 7, 2006 6:38:16 AM

Quote:
i have a similar question - i wanna connect my computer to my TV (a standard def, 4:3 Sony set), i have a ATI X800XTPE and was wondering which would give me the better picture quality, S-video or composite??


S-Video gives a slightly better signal, you can read some reviews to see the difference.

By the way, you're right and he's wrong, composite is a single RCA-type video cable used since at least the 1970's
October 7, 2006 6:38:34 AM

d00d, nearly all TV's have composite, as do VCR's.
October 7, 2006 3:32:02 PM

no problem my friend. it happens all the time. my brother has his own high end home theater/automation shop (innovative lifestyles, naples florida. http://innovative-lifestyles.com. sorry for the shameless plug) and he says people get them mixed up all the time.
October 7, 2006 3:36:41 PM

Quote:
good awnser


thank you.


in all honesty, you really dont need special component video cables. you can use normal "a/v" cables to send just the video signal. you then need another set of red/white cables to send the audio. all low end component/av cables are just a copper cable. nothing special about the component cables. i ran my dvd player to my sony set that way for a month until i bought a much nicer ($$) set of component cables.

...and I bet if you were honest you'd say you couldn't tell the difference between the low end cables and the nicer set just from the picture quality, rightt?

it is very true. you cant notice any real difference between the high and low end cables. i bought the high end cables a)my brother can get them rather cheap, b) they have much better shielding. i had to run them close to some power cables for some of my equipment and i was getting some artifacts from the power lines. the $$ cables removed that interference just because they were shielded better. but over all i agree, companies are just ripping you off on the expensive cables. unless you are talking about speaker wire. that is a whole different story.
October 7, 2006 6:45:51 PM

The only way I can keep those similar words from being mixed up is to remember what they mean!
October 7, 2006 7:32:10 PM

i still, have a question, since i ended up going to buy real component, and i ended up with the same results, ie. black&white but reddish tone.
i finally gave up and bought s video instead (it works!)
the question is: would i notice a difference in image quality between s video and component, my laptop being the source, if the tv is a sorta old crt (don't know the quality bought it used for $50)?
October 7, 2006 8:03:21 PM

no, you're fine. there would be little difference
October 10, 2006 3:53:31 PM

I suppose noone asked what kind of output you *really* have. In the US the term 'component' indicates Y-Pb-Pr, which is not R-G-B. When you see red-green-blue plugs on a TV as component input they do not indicate the actual color going across them, they are only there to tell them apart. On the off chance the laptop in question is using RGB output it will not be compatible with a tv that uses Y-Pb-Pr input, but you may get some usable video out of it like black and white, depending on how the tv chooses to decode the info.

As far as component video cables, you are all right in concluding they are no different from any other RCA type of coaxial (meaning sharing an axis), not to be confused with RG-6 which is a type of heavy gauge coaxial cable used in broadband cable TV delivery. I suggest anyone who is still confused should check out Wikipedia's articles on the above terms for further information.
October 10, 2006 4:50:34 PM

There is a lot of misinformation here....

Let me correct some since I do this for a living (broadcast film and TV).


Component, in regards to video, just means a signal that consist of several other signal. For example a PC CRT is a component monitor since it takes an analog signal from your video card (seperated in Red, Green and Blue signal).

For broadcast video - component signal is in YPrPb (analog component) or YCrCb (digital component) format.
HDTV, MPEG 2, Digital Beta = YcrCb
BetaSP (not the consumer Beta), analog outputs from your DVD = YPcPb.

Y= luminance information
Cr/Pr = subtraction of red chrominance information (it DOES NOT MEAN RED signal like in RGB)
Cb/Pb = subtraction of blue chrominance information


RGB = additive signal format
YCrCb = subtractive signal format

RGB has a wider dynamic range thus require more bandwidth.
The difference between RGB and YCrCb is very complicated and would require a lot more that one can do here. There is also sampling and bit depthand such. YCrCb for example sampled at 4:4:4 ratio can be as good as 8 bit RGB. (don't ask why)


Quality wise...
Component can theoretically resolve more resolution since it prevents signal cross talk between each component.

S-Video - was designed to allow SVHS (NOT VHS) by seperating the luminance with the chroma information (thus Y-C for short). Technically it is a component signal. But engineers avoids this term for S-Video since traditional component refers to 3 distinct signals.

Composite - luminance and chrom in one signal.


HOWEVER, unless your monitor can resolve more than what a signal can do it may matter very little how you can connect it.
For example, a typical standard definition consumer TV can only resolve between 200-400 TV lines.
Composite is somewhere upwards of 320 lines.



Bottom line - you can use any cable you want.
The color of the cable is just there for convenience. It has nothing to do with the signal. You can plug a yellow RCA to a RED connection. It does not matter. Of course it matters if you connect your video out to a audio in. You can use red/white/yellow cable to connect your DVD player to your TV as long as you send the Y/Green luma channel, Pr and Pb signal to the proper inputs.

The illustration below will work!
DVD TV
Y (green )<---yellow cable ---> Y
Pr(red) <----white cable-->Pr
Pb(blue) <---red cable---> Pb


People often confuse RGB with YCrCb/YPb/Pr.
They are related but not the same.

Expensive cables are designed to prevent noise and interferance. HOWEVER, most are overkill. Unless you are working in TV station that needs to run hundreds of feet of cable through rooms with hundreds of electronic equipment - your Radio Shack $10 cable will perform as well as your $120 Belden.


HTH
October 10, 2006 7:26:40 PM

Finally, someone else who gets it :D 
October 10, 2006 8:05:18 PM

I bet there are plenty of people here who "get" enough of it, yet won't take the time to explain what they know.
October 12, 2006 3:21:25 PM

The things you learn... :) 

Guess I'll have to try hooking up our DVD player to component input on the HDTV with regular A/V (red/yellow/white) cables. No excuse to not take advantage of it anymore. :lol:  Thanks for taking the time to explain everything you know, crimsonfilms.
!