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S-Video vs AV in outs

Gemini

Active Member
Any pros or cons on using S-Video versus regular AV in/outs between a DVD player and a projector?? Am I gaining or loosing anything other than the convenience of a all in one cable that S-Video provides??
 

huggy59

Active Member
S-video is noticably clearer and cleanly due to the signaling used vs. composite video. Use s-video when possible, unless digital video formats are available.
 

Treetop

Active Member
Worst to best ...

Analog:
1) Coax Cable (RG-59 vs. RG-6 -- Ill let you all dispute... I say stick with RG- 6)
2) Composite (aka. RCA, yellow (video) red/white (right/left channel audio)
3) S-Video (only video, common place, won't pass 480p+, still need audio cables)
4) Component (RGB -- video only... still analog though, but able to pass a HD signal)
5) VGA (been around the block, but the movie/cable/etc. industry can't include macrovision on it, so this will not be a contender for A/V equipement in the future)

Digital:
6a) DVI (different standards, still "young", video only, allows DRM)
6b) HDMI (new comer on the scene. Passes audio and video, but still allows of DRM to be tacked on, has yet to prove itself, but thus far has high marks (from the movie/cable industry mostly)
6c) I know Im missing one here... ??

Note: both 6's are equal at this time. The only thing that really seperates them from the pack is that they are digital, and as such the "government" can (and will) place digital rights management schemes on them.

Component, is the best analog feed out there, the problem is that not many devices (esp. A/V switchers ((ie. receivers)) ) aren't built to deal with them, though many Hi-end systems are getting the hint.

Since I mentioned Audio... Digital Coax vs. Toslink (optical)
This arguement can go one for days, but from all that I've read Digital Coax wins.

I use S-video throughout most of my set-up as its available on most devices. I use Component and DVI when and where I can... RG-6 (Coax) will always have a place in my home, though, as it is cheap and reliable.


_____
Any and all information contained in this post is more than likely incorrect, and if nothing else, can spark a great debate of which one is better.

Tree
 

electron

Administrator
Staff member
That's some great information Tree, mind if I add some of this to the Glossary? As for Digital Coax, I never heard of it, but noticed my receiver supports it, but I thought the TOS link was better (and supported by both my HTPC and cable box), so that's what I invested in. Do you have more info on the digital coax?
 

smee

Senior Member
Coax vs. fiber optic digital connections: Be careful, you don't know what you might be starting here. A lot of the arguments (literally) center around things like the coax being able to support higher bandwidth. But, the counter arguments contend, it's the same digital signal so you don't need more bandwidth. It can go on and on and on and on and on...

And if you hear the word "jitter" mentioned, just run away. B)

If you search the forums on www.avsforum.com you'll find plenty of material.

The upshot is usually that most of us mere mortals can't tell the difference. I use both in my system. I like using optical for one long run (30 feet) because it isolates the two devices and you don't need to worry about grounding, etc. Also, my receiver only has one coax input and I use that for the DVD player. Everything else needs to be optical anyway.
 

huggy59

Active Member
Hehe, Smee's right, it is a real mudbog out there! I tend to lean toward optical just because it does away with any possible ground loops and common mode electrical interference. But hey, when it comes down to it, you use what works the way you want, any way you can hook it up.
 

Treetop

Active Member
mind if I add some of this to the Glossary?

Nope, don't mind at all... glad I could contribute.

Regarding Digital Coax... I forget where I read what I read... probably AVSforum. Not even sure what makes me think that coax wins over Toslink (I think the thread I read was about 10 pages long)... Personally, I use one Toslink cable in my entire setup... works well enough for me.

I think huggy hit the nail on the head when he said, "...when it comes down to it, you use what works the way you want, any way you can hook it up. "
 

Gemini

Active Member
Thanks, for more than I ever wanted to know! B) Looks like S-Video is my best option.
Thanx, Rick
 

TechTooth

Member
Right guys, this is my area!
I worked as a product tester for just over a year in a sourcing office in Shanghai for Best Buy and frequently had to explain exactly these kinds of things to the sourcing managers.

What TreeTop said is for the most part absolutely correct, however there are a few more things that need to be taken into account than just the quality of the connectors.

Composite a yellow labelled RCA connector is usually coupled with your analog stereo audio and most commonly know as the "AV" cable works in exactly the same way as the R-59/R-6 coaxial cable and provides two signals that have been combined, Y and C. They then have to be seperated to display a picture on your screen. Y is luminence (essentially the picture in B&W) and C is chrominence (color).

S-Video keeps these 2 signals separate, if you look down the end of the connector, you'll see 4 pins and a plastic rectangular shaped thing. The plastic is just to guide it in nicely as to not bend the pins, 2 of which carry the +ve and -ve Y signal and the other the +ve and -ve C signal.

If you are viewing a signal from a DVD player or other fairly high quality source (D-VHS player, PC, Digital Cable Box), the S-Video cable will always produce more accurate results, since the signals are already seperated to begin with.
They would have to be combined to pass through a composite cable and then seperated again by a filter in the TV to create a picture.
So, Gemini this is your prefered choice.

Now here is the tricky bit, if you are using a regular VCR or terrestrial TV through your VCR or other device as your source, the signal is already combined to begin with! So now, the question is which is your best Y/C seperation filter? Is it the one in your VCR or is it the one in your TV?
If you have a plasma screen, chances are that it will have the better one, in which case you should use the composite/AV cable and let the TV do the filtering.

If you don't know which is better, compare the 2, it will depend on your own configuration.

I could go into this a lot further and talk about different Y/C seperation filters, but it will go on for a fair bit, so I'll abstain for the moment, but feel free to ask me later if you're interested.

Instead, I'll touch on some of the other cables mentioned and oh yeah, I just wanted to mention that S-Video does not have the bandwidth to support progressive scan so can only support up to 480i, not 480p (sorry Treetop but I'm pretty sure about this).

Component/RGB cable: This is a cable that has 3 RCA connectors labelled Green, Blue and Red, however the component signal IS NOT the same as a RGB signal.
The Component signal, often called and labelled Y Cb/Pb Cr/Pr sends the actual picture signal through the Y cable (labelled green) and then components of the colors through the other 2 (I'm not going to go into how much %age-wise, it's too technical and I don't know it off-hand).
You guys may have noticed that I'm talking about Y and C again, right? That's because the component signal is just a further breakdown of the 2 signals passing through a S-Video cable, meaning less combining and seperating of signals (this time color-wise) to be done before and after the data transfer from your DVD player to your TV.
This cable is actually usually passing a digital signal (although it can pass an analog one) and is therefore capable of transmitting HD signals 1080i and even 1080p (in development, but I've seen it).

This cable is slightly better than using a VGA cable and is going to give pretty much the same results as a DVI cable.

Gemini, if you have a progressive scan DVD player, I would HIGHLY recommend you use this cable, this will dramatically improve the picture given by your projector. If you want to just try it, you can use your AV cable and just plug yellow into Y, white into Cb/Pb and red into Cr/Pr. It will work and look better than with your S-Vid cable, but eventually you should get a proper component cable to reduce signal loss (they are usually thicker and have gold cons).

As for DVI, shit this is getting long, there are 4 types of DVI connector, DVI-A, DVI-D, DVI-I and DVI-M.
DVI-A is analog.
DVI-D is digital.
DVI-I is integrated (both analog and digital).
DVI-M is a mini version of DVI-I, it has a different connector but leads are available to any of the others and it is compatible with all of them.

Right, now digital audio, the moment you've all been waiting for, lol.

OK, the coaxial digital cable we are talking about here is just an RCA cable (all RCA cables are in fact coaxial, they just look different to the R-59/R-6 one).

So, coax or optical(toslink)?
Right so even though I agree with smee when he says:
most of us mere mortals can't tell the difference
i've tested hundreds of products with both and I have never been able to tell which is better.
However, from a purely technical point of view (this has been tested with sofisticated equipment), coaxial is better under 8 meters and optical is better above 8 meters. There you have it! Basically that is the point when light starts to outperform metal in tems of signal loss.
However, make sure you don't bend yopur optical cable or walk on it by accident, the quality may go waaaaay down!

Sorry for the long answer guys, but it should cover most things. Tell me if you want to know more about DVI or Y/C seperators. I only touched the surface on them. Also I could go on about RG-59/RG-6, it can actually carry a digital signal, damn, better stop myself now...

And by the way, HDMI, I agree with Treetop, nothing to add.

Edit: fixed a couple of typos and formatting, also clarified a small part.
 

electron

Administrator
Staff member
that is one heck of a post you made there, I learnt a lot from it, thanks for taking the time to type that all out!
 

Treetop

Active Member
S-Video does not have the bandwidth to support progressive scan so can only support up to 480i, not 480p (sorry Treetop but I'm pretty sure about this).

No need to be sorry... we both agree! :)
3) S-Video (only video, common place, won't pass 480p+, still need audio cables)

Great run down. Being that I don't have any devices that use a DVI connection, I never really knew about the differences (only that they existed).

Never thought about the length of the audio cables coming into play. Makes sense, though.

Also I could go on about RG-59/RG-6, it can actually carry a digiatl signal, damn, better stop myself now...

Don't stop now :D

Now ya got me all curious!
 

TechTooth

Member
Glad you're interested!

On Treetop's request I'll go into my experience with using an RG-59/RG-6 for transmitting a digital signal.

In essence, these cables are no different from the RCA coaxial cables that are used for composite video, component and progressive video, stereo audio, digital coax audio and LFE from your Amp to your Subwoofer. You can get cheep ones and good quality ones, the main difference is the connector (F connector, commonly known as RF).

I used to call this an RF connector as it is commonly used for terrestrial TV (which is a poor quality signal to begin with) and if you are using it for this purpose you don't need any better than the classic screw-on silver connector (color not material). There is a cheaper version which just plugs on without needing to screw it in and the more expensive Monster cables that have a thicker core better insulation and gold-plated cons.

If you use this more expensive one, it is likely to be actually BETTER than using an RCA coax (at least for the application I am about to describe), as you screw it in and it has a more perfect fit.
Feel free to argue this point guys, I don't have any solid tested info on this, I was just told by someone more qualified and experienced in CE than myself.

So when is it used?
In my case I used it to transfer a coded digital signal from a HDTV signal source to a digital set-top box which then decoded the signal so it could then be transmitted through either DVI or component cables to test TVs for 1080i and 720p compatibility.
For you guys, cable digital (ATSC).

If you want to know more, here is a link to similar testing equipment:
HDTV Player
and here is a link to ATSC's standard for DTV digital data compression over RF (see page 20):
Guide to the Use of the ATSC Digital Television Standard

Hope that covers it.

Would anyone be interested in me writing an article on Y/C seperators?
Why you pay more for 3D adaptive comb filters and the like...
It may have been covered already I don't know, and I do tend to get a bit technical when I get into something...
Gimme feedback!
 
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