Differences between connections

[Inventive Software]

Curious as I am, I'd like to know what sort of differences there are between hardware connections between say, a DVD player and a TV.

I took a look down the back of a DVD player that was on sale, and saw several connections. Some of them I know about, others not so. There was:

## A SCART hole, big black thing that could have a SCART lead attached. This makes for easy connection to the TV provided it has a SCART hole as well.
## A Composite hole, yellow in colour. This one I know about as well, and have used many times in connecting a VCR to my PC.

Next to that we have:

## L and R audio holes, White and Red respectively. Again, I know about those ones.

Not far from the SCART and Composite holes, there's:

## An S-VIDEO hole, presumably for an S-VIDEO lead. I've had absolutely no need to use this as I've had more troubles and hassle with it that would take up pages to rant about. 'Nuff said. ;)

These are the ones I don't know about. Near the L and R holes, there was a Coaxial hole, the same type as the L and R and Composite holes, but I have no idea why this is there and what it's used for.:confused: What does it offer over the L and R sockets?

Further down the other side, near the SCART socket, there's three holes the same size as the L and R and Composite holes, imaginatively titled "Y", "Cb/Pb" and "Cr/Pr". I know a little about these, but not what they offer over the SCART, Composite and S-VIDEO sockets. Do they give a clearer picture? Or are they there just to confuse the average consumer as to where to put his connection leads.:rolleyes:

[jggimi]

The owner's manual that comes with a player will tell you a lot about those connections.

You've only had trouble with S-video because you've tried to use it *through* SCART. By itself it produces higher quality video than composite, since luma and chroma are sent on different wires.

The 3 RCA connectors are for component video. It is higher quality still than S-Video, and the highest quality available for analog video.

If you look at other DVD players, you may see a DVI or HDMI connector on the back. Those are for digital video, which this particular player did not offer.

----

The coaxial connector was for digital audio -- one connects this to a digital surround sound system.

On other players, you may see a fiber optic connector with or instead of the coaxial connection, for the same purpose.

[Awatef]

I think the Red/Green/Blue connectors are mandatory for progressive scan. Both DVD player and TV must support progressive scan of course. The DVD player you're talking about seems to support Progressive Scan since "Pb" & "Pr" are mentionned.
As you may know, a progressive scan signal is better than a common interlaced signal (better definition, less flickering)

[jggimi]

This is true, 480p analog requires component video.

[CWR03]

The coaxial connector was for digital audio -- one connects this to a digital surround sound system.
Isn't the coaxial connector just the normal channel 3 or 4 output for an older TV with no other inputs than a 75 ohm cable signal?

[jggimi]

On a DVD player?

I suppose anything is possible, but I've never seen a player with RF-out. These are normally SP/DIF outputs for surround sound.

But, as I said above, the owner's manual is a terrific resource to answer these questions.

[Awatef]

Near the L and R holes, there was a Coaxial hole, the same type as the L and R and Composite holes

So he's definitely talking about a digital audio output :)

[Audionut]

Viedo in order of quality.

Composite. Yellow socket. All video information gets sent down the 1 cable.

S-Video. Small round black socket with slots for 4 pins. Sends the video down 2 cables. 1 for Luma and 1 for Chroma.

Component. 3 RCA sockets. Sends the video down 3 cables. 1 for luma (green socket (Y)), and 2 for the chroma signal (blue socket (PB)) (red socket (PR)).

Scart. Big black socket. Splits the video into red, green and blue, and sends each signal down it's own wire. Also sends the timing signal's down their own wire.

DVI and HDMI. Digital video cable. No digital to analog conversion. Video gets sent to the tv as the original digital signal.

With a test dvd, you can easily see the difference in quality between composite, s-video and component signals.



Audio in order of quality.

2 channel analog output. 2 RCA sockets. White is the left audio channel, and red is the right audio channel. All 6 channels of audio information gets mixed down into 2 channels.

6 channel analog output. 6 RCA sockets. Front left and surrond left are white. Front right and surrond right are red, and centre and LFE (low frequency effects (sub)) are black. Each audio channel gets it's own cable.

Optical digital output. 1 small square black socket. All audio information gets sent in original digital format to the reciever.

Coaxial digital output. 1 orange RCA socket. All audio information gets sent in original digital format to the reciever.

From what I have read. Coaxial cable is the "better" of the digital connections.


Analog vs digital.
With any of the analog audio connections, the original digital signal gets converted to analog, then transmitted down cable with constant interference bombarding it, then gets amplified (interference included).
With digital, there is no possibility of inteference. As digital is either on or off. Thus anything else is noise and gets discarded by the reciever.
The same goes for video signals.

[GodofaGap]

Why would coaxial be better than optical if both are digital? I can't imagine any signal distortion on such a short cable.

[Audionut]

1. Light leakage
2. with cable bends, the light constantly reflects.

I'm talking pure theory here. In practise, their both as good as each other.

[GodofaGap]

The whole point of an optical cable is that it reflects inside the cable... otherwise it wouldn't work.

You are aware that for long-dsitance communication optical cables are used right, not electrical ones?

[Audionut]

"Total internal refection confines light within optical fibers (similar to looking down a mirror made in the shape of a long paper towel tube). Because the cladding has a lower refractive index, light rays reflect back into the core if they encounter the cladding at a shallow angle (red lines). A ray that exceeds a certain "critical" angle escapes from the fiber (yellow line)."

http://www.arcelect.com/fibercable.htm

edit: sorry, should have phrased no 2 better.

[MuttLover]

Thanks for the info on digital audio, coaxial vs. optical. Now I've read both opinions, one saying optical is better and one saying coaxial is better, the best comment being that "in practice they are about equal".

That always confused me, so I guess either is just fine.:thanks:

[mpucoder]

Here's one for optical - electrical isolation. This translates to no ground loops or cable failures due to ground fault current.

[jggimi]

Another reason for selecting optical is distance -- but that's usually not applicable in a living room or home theater. :)

[Inventive Software]

Wow, thanks guys! I wasn't expecting this sort of response.

A related query: the DVD player in question had 2 words on the front that made my heart skip a beat (though that may be to do with my heart condition, I'm not sure ;)). "Progressive Scan". I take it that this means it outputs progressive video, but how do I tell if my TV supports it (progressive) if I don't have the manual? It has SCART and composite sockets, but can't see component video sockets anywhere. :(

[Audionut]

Basically CRT tv's can't handle progressive scan. There might be a few select CRT tv's that can handle progressive scan. But you would know if you had one.

Therefore you need a plasma or LCD display panel.

edit: As far as I know, all plasma and LCD display's are progressive.

[dumbas..]

Further down the other side, near the SCART socket, there's three holes the same size as the L and R and Composite holes, imaginatively titled "Y", "Cb/Pb" and "Cr/Pr". I know a little about these, but not what they offer over the SCART, Composite and S-VIDEO sockets. Do they give a clearer picture? Or are they there just to confuse the average consumer as to where to put his connection leads.:rolleyes:

All I know is that component give a superb picture on my projector to a 112" image. S-video was ok, but a bit blurry and grainy. I believe that component give a signal that is derived 'direct' from the dvd (i am sure I will be corrected on this in some way:rolleyes: ) and does not depend on conversion.

Like all things a little research showed me the way to go. I would rather have the option to use any / all of the conections than be restricted to scart/ s-video like many machines I looked at. Spent £40 and got a very good picture.....