Query on RGB and Component

[Light]

Ok, got a couple questions regarding TV's and stuff which hopefully someone might be able to clue me in on, as I am completely hopeless at this. Here goes...

1) What's the difference between RGB and composite? I've tried running metroid prime (american version) on a multi-system tv first using composite leads then with an RGB scart cable and don't think I saw any difference in picture quality. And where does S-video fit in to all this?

2) If a game doesn't support progressive scan, can I still play it on an HDTV using composite, RGB or using some other cable?

3) Is there a greater difference in visuals between an xbox360 game running on a regular tv and then HDTV, rather than a current gen game running on a reg. tv and then on HDTV? I mean, where is the jump in visuals more noticeable? I presume with the 360 games...

4) VGA cables. Do these produce a better picture than RGB or component? And can they be only used on CRT monitors?

5) Are all american games run automatically in 60Hz? I mean, a PAL tv can't display an american game in 50Hz, right?

6) If I'm running an american game on a regular PAL tv (that accepts 60Hz) using an RGB scart cable, and the game doesn't support progressive scan, then am I generating the best possible picture that I can get for that particular game? Or will it still look better if I use all the same equipment, just change the TV to an HDTV?


I know that's a lot of questions, but I'd greatly appreciate any help on this chaps.

[EvilBoris]

1) There is quite a significant difference, you should be able to spot it straight away (especially in metroid prime as all the thin coloured lines become much sharper) make sure that RGB is turned on in any options on the TV, that the RGB lead is plugged into EXT. 1 on the back of the Tv (most tvs only do RGB in one scart port). And remember that american and japanese cubes can't do RGB without a pricey and hard to come by cable.

2) Yes, but due to the nature of most LCD tvs it will look rather blurry.

3) The Jump between standard TVs and HDTVs with 360 is usually fairly noticeable. Its just a case of the games looking MUCH sharper in HDTV, underneath it is the same game.

4) VGA will produce a vastly better picture than an RGB scart and a mildly better picture than component (but only if you are talking about official VGA leads like for Dreamcast and Xbox 360). They can be used on any kind of monitor , LCD or CRT.

5) American games can't and don't run in 50hz at all.

6)CRTs are better at displaying the Standard definition stuff and HDTV can obviously do the HD stuff and look lovely.

I use my LCD HDTV for everything (and most stuff looks fantastic), but non progressive scan games i.e. almost all PS2 games look rather blurry. Xbox and CUbe games generally support prog scan and look lovely

[Light]

Ah... cheers for that boris.

Two more things though... is S-video better than RGB?

And you mentioned that official VGA leads are better than unofficial ones... can the same be said for RGB scart cables? For example, I'm using a Logic 3 scart cable for my ps2... should I purchase an official one instead though?

[EvilBoris]

RGB is better than S-video.

What I meant by official VGA leads was that VGA is only good on consoles which properly support it. 3rd party companies make VGA leads for gamecube and PS2, but the picture is a hideous blurry mess.

Usually official products are better , but there are also some good quality 3rd party things too. It might be worth upgrading that Logic 3 scart, l3 are the cheapest of the cheap, it might not even be an proper RGB scart

[Light]

Oh, I gotcha. Thanks.

[vertigo]

1) What's the difference between RGB and composite?

In your title you say Component, here you say Composite. I think you mean Component, because if you can't tell the difference between Composite and RGB you seriously need your eyes testing. Do not get confused between Composite (three wires; yellow for a combined video signal, red and white for sound) and Component (three seperated signal video wires; red, green and blue, with additional sound wires). In which case:
RGB and Component are just about the same. Of course, the super-elite will have you believe differently, but the gap between RGB and Component is nothing like the gap between Composite or S-Video and RGB. If you only have a standard-definition TV that can do RGB and not Component, you're not missing out on much. Still, the only way to get hi-def signals from your consoles is to use Component cables as it's generally not supported by the SCART socket (although the SCART standard does allow for it, it's extremely rare that you ever see it implemented by a console or TV manufacturer) so if hi-def's what you're after, use Component cables instead.
You say you didn't see much difference running Metroid Prime in either one. That's probably about right too. The Gamecube internally uses Component colour space which is then converted at the end so its Component output is fantastic but its RGB output (via hacked-together digital and multi-out cables for NTSC machines or an officially made RGB SCART cable for PAL machines) is extremely good too. What you will notice an obvious difference with is running Progressive Scan vs Interlaced Scan. Hold B on start-up to enable it, if your TV supports it. One strange thing about Prog Scan is that some games actually look worse in it. Resident Evil 4 I believe has been cited as one example that actually looks worse in Progressive Scan. I don't know why, it goes against what you'd expect, but some games just do.
Another bizarre thing is that even using RGB most of the PS2's output still looks like crap, but switch to Component, which isn't all that much of a step-up in real terms, and the PS2's output is leaps and bounds better than its RGB output, so the PS2's video chip and colour space must have been designed with Component in mind as opposed to RGB. Not that Sony had the sense to market it that way at all, but they didn't really need to trumpet tech specs where about 0.5% of the audience would understand what they meant, when they could just promise the moon on a stick instead

[gIzzE]

You have to be a bit careful when looking at these things, as Vertigo says, not much between component and RGB......when all things are equal!

The best connection on paper is RGB, there is nothing to stop you sending up to 1080p over scart, however it was not part of the spec so it will no be found on any connector (Loewe did have a set that would accept component and RGB over scart but that was a one off) but RGB is actually more capable than componet.

RGB is Red Green Blue all seperate and then sync signal, which is as follows...

RGBhv=Seperate colourspace and the Horizontal and Vertical syn is seperate too (You then get bi-level and tri-level sync too, but we won't go there. Often wrongly called VGA.
RGBs=Seperate colourspace and then the sync is combined but seperate. Used in scart with composite as sync and luminance.
RGsB=Sync on green, so seperate colour space but the Sync is embedded in the green signal. Not much uses this.

Component is in basic terms the luminance and sync on green, and is called Y, and then the colour difference sent on the red and the blue cables, so only black and white is sent on green and then the blue and red - the green is sent on the B-Y and the R-Y cables.
So to save bandwidth black and white, red and blue is sent, the display knows how much black and white there is from the Y channel and it knows how much blue and red is there from the b-y and r-y channel so it then also knows the rest is green saving bandwidth.

S-Video=Y/C
S-Video is basically Component but it combines the B-Y and the R-Y channels to save even more bandwidth, but good S-Video can be very good, although it can't go passed interlaced.

Composite Combines the Y and the C channel from S-Video and is generally very poor and should be avoided if possible.


Now the problem is not the signals but what your source and your display does with those signals.
A dvd player stores the info in interlaced 4:2:2 YCrCb Component video so ideally you should output component right??
Hmm,what if your display converts componet to RGB, and does a far worse job than the player does at converting to RGB.
So you output RGB, that should look better right??
What if you TV converts all RGB signals internally to S-Video?? Alot of TVs do, the reason being Joe public likes to be able to mess around with the picture controls, so the TV converts RGB to S so you can still adjust Colour. Not all TVs do, Sony sets don't, but alot do.
If you can adjust your colour settings your TV is taking RGB converting it to S-Video (or maybe component) and then converting it back to RGB again, and unless the TV is very expensive each conversion will degrade the original signal by quite alot!

Same with the Source device, some have an excellent S output but poor component.
You have to try the different combos, but don't be surprised if S-video looks better than 1080i over hdmi, black is not always white!

[Light]

Thanks for the input chaps, here's what I did...

I first fired up metroid prime on a standard tv... using composite and then RGB (the RGB cable I'm using is a modified one, since my gamecube is american). I noticed a difference between the two... the picture didn't have any lines running across it from what I could tell, and generally seemed sharper when using RGB. It also seemed less "foggy"... a bit darker than the one the composite generated.

Then I brought everything over to the HDTV we have in the living room and here is what happened...

As EvilBoris said, composite gives you a rather blurry picture and looks worse than on the tv I used previously.

RGB on the other hand seemed fine... I didn't notice any blur or anything, and it definitely looked sharper.

Then I turned to my component cable and ran the game in progressive scan mode... but I couldn't really tell the difference between that and RGB... in fact, when I go into morph ball mode, a bit of the top picture is cut off, so I can't really tell how much health I have for example. But this only happens with progressive scan mode and interlace mode... it doesn't happen when I use composite or RGB. Why is this?

Speaking of which, what exactly is interlace mode? If I decline progressive scan it switches to that... but I honestly can't tell the difference between those two either. One's 480p, the other is 480i but what does it mean really???

[gIzzE]

I take it from your description you are using a progressive display?? Either lcd, plasma or DLP.

If so your display is showing everything progressive, if you feed it progressive it just scales the image to fill the screen, if you feed it interlaced it will deinterlace the image and then scale it to fill the screen.


Lets take 60hz material as an example.

NTSC is 720x480 interlaced at 60hz, it shows the first 720x240even lines of the picture and then then in the next pass it shows the 720x240odd lines, this happens 30 times a second giving you a total of 60 frames, but you only ever see 240 lines of resolution.

Say your screen is an lcd and it is 1280x720, it has to do the following.....
Take the 720x240 lines and store them, it then looks at the next 720x240 lines and stores them, it will then piece together the two frames and and look at that, it then has to add all the missing details to make sure you stretch that 720x480 image to 1280x720p so it fills the whole screen, this is called scaling. This is also why you get lip sync errors when using an external amp, the video is delayed to do all this working out.

If you feed it progressive you are giving it 720x480p 60 times a second and no deinterlacing has to be done, you also have a true 480 lines of resolution, it is not your screen adding what it thinks should be there. All your screen does is scale the image to fill the screen.

If you did this on a CRT projector the difference would be obvious as you would see the lines on screen in interlaced mode.

You can now see why feeding the screen 720p is better, no deinterlacing and no scaling (in theory on the scaling but that is another matter) so you should get a much sharper image.

Feed it 1080i and you are causing all sorts of problems, when you feed an LCD 1080i it downscales to 1920x540p and then it has to rescale back to 1280x720p, not a nice thing to have to do, try resizing a photo in photo shop to 1920x540 interlaced and then back to 1280x720, it has all sorts of funny artifacts going on round edges, alot of people mistake this noise for the image looking sharper, but look at a test pattern and you will see you are throwing detail away.
That is why feeding a progressive display upscaled 1080i dvd is one of the stupidest things you can do, but marketing has everyine believe you should be doing this!!

[Light]

Cool... not sure I understood all of that, but thanks for taking the time to explain it though gIzzE.

[gIzzE]

Basically your screen will turn everything into a progressive image, so you won't notice much difference between interlaced and progressive.

If you look closely though, you should see the progessive image looks a lot smoother.