I think I can safely say that in terms of picture quality, Component video is better than S-Video, which in turn is better than composite video.

But, where does the "normal" (European SCART connection) RGB rank compared to these?

Background: My multi-system TV has two SCART sockets. Each of these can be set for composite, S-Video, or RGB, but the TV set is too old to take a component video feed.

My VCR and DVD offer composite, S-Video, and (DVD players) component video outputs only, but no RGB. I am currently feeding S-Video from my DVD players and VCR, as this is the "best quality" signal that all equipment can work with.

Recently, I have found devices that convert S-Video or component video to RGB.

What I want to know is: Do I gain enough picture quality over my current S-Video feeds to make purchasing a S-Video to RGB converter (about $325) worthwhile?

Do I gain enough over component video to buy a component video to RGB converter (about the same price)?

Thanks in advance for your advice and assistance! -Bruce

Bruce,
Hi there. My understanding is that, all else being equal, the quality of RGB tends to fall between component and S-video. This depends greatly on the cabling though, eg top quality S-vid cable will outperform average RGB cable. This means that:
a) You would need top-line scart cable like QED Squart. (£50 British money, so maybe $50-70.)
b) You need to be sure that the converter uses quality materials hence retaining the intended detail, colour definition etc.
c) As RGB is (and I use the word loosely) better than S-video, you would achieve little converting from S-vid.
d) Theoretically, you would see an improvement converting from component to RGB. How significant, and whether it's worth the cash, is something for you to decide. Maybe you've a friendly retailer who will allow you to loan the bits for a trial? Good luck whatever you choose.

Dan.

"My understanding is that, all else being equal, the quality of RGB tends to fall between component and S-video"

RGB is the highest quality signal you can have.

ALL video signals start out as RGB.

This may be of some help.

Thanks for your responses so far. It would appear from everyone's comments and djy's link that RGB is at least comparable to component video.

From all I've heard, component is so superior to S-video that I think investing in an S-Video "upgrader" is almost certainly worth the money.

Component to RGB "transcoding" sounds more problematical. I'll have to think about that a bit more.

I would appreciate hearing from anyone who has had the opportunity to personally compare RGB to either S-Video or component video. Thanks again! -Bruce

Bruce, keep in mind that converting a video signal will not make the signal suddenly become the higher definition signal. This conversion is only going to allow a single connection to your display.

As with most things, the weakest link prevails.

Larry
www.fineelectricco.com

" RGB is at least comparable to component video."

No, RGB has a wider bandwidth and is superior to component.

Larry,

The single connection is no problem. I route all sources into the receiver first, then send a single S-Vid connection out from the reciever to the TV monitor.

So I would just drop the converter between the receiver and TV.

But now I'm concerned with your remark about signal quality. Here's a description of the box in question:

RGB/YUV VIDEO STANDARD CONVERTOR
A handy gadget that can convert composite to s-video (both ways) and either to colour difference YUV or RGB signals. All commonly used connections and switches are on the front panel making for a easy "rack" type installation. Great for connecting DVDs and other video sources to video projectors and large screen TV's with component or RGB inputs.
Technical spec:
Video inputs: 2 x composite (RCA), 2 x 4 pin s-video
Video outputs: 2 x composite (RCA), one composite/Horizontal sync, one vertical sync, 2 x s-video1 x YUV or 1 x RGBHV (switchable)
Audio inputs: 4 x stereo pairs RCA phono; Audio outputs: 3 x stereo pairs RCA phono
Power supply 15v DC 450mA (UK adaptor included); Dimensions 370(W) x 75(D) 50(H) mm
Order Code [CMT7] £199.99

For 200 British pounds, I expect more than just a widget to plug an S-Video cable into an RGB SCART socket. My understanding was that this device will actually upgrade the quality of the signal, not just change the format / standard.

Since I can already set the SCART socket to accept an S-Video signal, the only reason to buy this box would be if I can use it to upgrade the signal quality! I guess I'd better go back to the vendor for more details... :(

Bruce,
What Larry is saying has to be correct. Rubbish in, rubbish out. Perfect in, perfect out. Think about it this way. A DVD contains a near-perfect rendition of a movie. We all spend our money on components that can accommodate and process this signal down to the finest detail, but we cannot actually improve what is on the disc. We can only strive to ensure that none of the content is lost by, say, having a crap AV Amp that ignores the extreme frequencies, or a cable that uses lower-quality materials and so loses some of the more subtle atmospherics.
In other words, the converter cannot really 'improve' the signal because it wouldn't actually know what to do to make it look better.
If we apply this to what Automan1 said (thanks for the info!) then you would gain *some* improvement on your current setup from converting component to RGB, but none by converting from S-Vid. The extent of *some* would depend on the converter's ability to retain the detail/clarity etc between the component in and RGB out). At best (and at £200 this ought to be the case!), you would achieve a component-quality signal.

Incidentally, (and I may be raising my head above the parapet for some abuse here!) receivers are sometimes not great at passing video signals (depends whether the maker included it merely to 'keep up with the crowd'). Have you tried a comparison by connecting the S-video source direct to the TV?

Or you could just spend the cash on an RGB-capable DVD player. As for the VCR, it's only VHS anyway...

Regards,
Dan.

"My understanding was that this device will actually upgrade the quality of the signal"

You misunderstood.

"...you would gain *some* improvement on your current setup from converting component to RGB,"

No you wouldn't. As i've said, RGB is the originating format, it is wideband, high quality. Component is bandwidth limited and matrixed...it's a form of analog compression. Converting a lower quality source to RGB will not improve anything.

It kinda like a digital recording. If you convert it to analog with a DAC, then back to digital with an ADC, you will never regain the original digital resolution or dynamic range. Likewise, with a video signal, whichever component or cable has the lowest resolution in the signal chain will reduce the picture quality to that resolution. Nothing can return a higher signal quality.

With a converter, you can make render formats into one common one for single-input cabling into the display device, or select a particular format for the least signal degredation over a long run, but converting, for instance, a composite or an S-video signal to a component signal will not provide you with a component-quality signal. You will merely have a composite- or S-video-quality signal traveling over a component connection.

That's why people are concerned with having a receiver that will switch component video, and do so with a full bandwidth. Once signal detail has been lost, it's lost forever. Same with audio, RF, etc.

Larry
www.fineelectricco.com

Well, I'm still waiting for a reply from the vendor, but it looks like "we" already know what the answer will be... no point in "converting" a composite or S-Video signal with an expensive box, since the SCART sockets are already switchable to take composite or S-Vid directly.

Btw Dan, thanks for your concern. I did in fact test whether running the video through my receiver would degrade the signal. Thankfully that does not appear to be a problem with this receiver. I agree with you whole-heartedly, and you can find several threads on this forum where I have recommended direct "source to monitor" video connections to others.

What looks interesting now is the box I initially paid little attention to, that will convert Component video to RGB. Since the Component signal is much better than S-Vid, it might be worth the expense to be able to watch DVDs at the "component via RGB" level on input1, while running S-Vid from the other sources directly into input2 (as I'm already doing :)

Automan,
sorry, you've misunderstood me. I'm saying that as component is superior to S-video, converting from component to RGB will leave Bruce with a component-quality signal, whereas converting S-video to RGB will leave him with an S-video quality signal. Therefore, converting from S-vid is pointless, but there would be some relative improvement on his *current setup* (ie S-vid) by converting from component. I !don't! mean an improvement from component to RGB signal quality. We know that's not possible.

Curiously though, the www.techtronics.com link in the 4th message above (thanks djy) suggests that
1) A TV/movie camera outputs the video signal in RGB.

This is essentially what Automan said. Just after that, however, it also says:

2) A DVD disc is recorded with Component Video signal in digital format. Hence Component Video is the best format to display a DVD on a TV. This format is common in US and Japan.
Most European/Asian/Australian DVD players converts and output the signal into RGB, without any noticable effects on video quality.

Now, we've already agreed that you cannot regain quality, so (according to the above) if you watch a DVD, you're down to component quality to start with. This would appear to suggest that although RGB is better for most sources, component is better specifically for DVD's, as that's what's on the actual disc. If the source and output are progressive scan component video capable, then the rendition of the disc's data should be perfect. Viewing in RGB (hence another step in the signal processing chain to convert the component signal to RGB) would theoretically provide (at best with good kit) a non-prog scan component-quality signal or (at worst) a component-quality signal minus the conversion overhead/detail loss inherent in a poor quality RGB conversion process/scart cable. Thus (stay with me folks!), if all this is correct, then if you (Bruce) can convert the component quality signal to RGB with no loss of detail/clarity etc, then you will see an almost-perfect picture (and with prog scan, even better), because RGB should not (from what Automan said about higher bandwidth/compression) hinder the signal at all, leaving Bruce with a component-quality source from the way the DVD was encoded originally.

Sorry, I know I go on, but I like techie stuff!

Don't suppose your kit's got prog scan then?!
Dan.

This message was edited by dan_flower on 04/18/02 07:13.34.

Dan,

No, unfortunately the monitor is too old (1997) for progressive scan.

You all were right, of course: I received confirmation that the S-Video converter does nothing to improve signal quality. It is designed for those unfortunates who have a "RGB only" capable set.

Since my SCART sockets are also S-video capable, I only need a small widget (it cost me 7.99 British Pounds) to mate a 4-pin S-Vid cable to the SCART socket, instead of the expensive box. That's where I got confused: I kept thinking that since the box cost so much, I had to be getting "more" somehow.

It does look as though it will be worth buying the component to RGB converter. That purchase is not very high on my list at the moment, but when I get it, I'll let you know how well I like it. New speakers, cables and cabinetry come first, so it'll probably be a while.

Thanks to all for your advice and assistance! -Bruce

I believe DVDs have video stored in 3-part component video, not RGB.

Also, you MAY experience an improvement with a conversion process. But only if the external converter does a better job than your TV does internally. This is totally system-dependant, though.

This message was edited by Spiky on 04/19/02 10:29.27.