Universal System Selector

[Unleaded Logic]

Shadoop shadoop shadoop...

I will explain something.

RF, Composite (RCA), and S-video all use the same exact colour space and specs. The only difference is what wires they are carried on.

You can convert from RCA to S-vid and back very easily, no power is even needed to perform the job. You can get little converters the size of a pen cap.

RF to RCA does require power though, but is still such a simple task that most of these switch boxes do it.


To check, IF the switch box supports RF/RCA/Svid AND has a power cable then it will most likely (unless for some reason they are retarded) support outputting any input as and of the given output types. Good thing to look for is the descriptions (Built in RF modulator).


Converting between these three types is NOT a process of upscaling. It's a simple redistribution of the wiring.

So wait...there is no quality advantage what so ever over using s-video over a composite cable? So when people claim that s-video is better, its really non-sense?

[dlmvii]

Shadoop shadoop shadoop...

I will explain something.

RF, Composite (RCA), and S-video all use the same exact colour space and specs. The only difference is what wires they are carried on.

You can convert from RCA to S-vid and back very easily, no power is even needed to perform the job. You can get little converters the size of a pen cap.

RF to RCA does require power though, but is still such a simple task that most of these switch boxes do it.


To check, IF the switch box supports RF/RCA/Svid AND has a power cable then it will most likely (unless for some reason they are retarded) support outputting any input as and of the given output types. Good thing to look for is the descriptions (Built in RF modulator).


Converting between these three types is NOT a process of upscaling. It's a simple redistribution of the wiring.

So wait...there is no quality advantage what so ever over using s-video over a composite cable? So when people claim that s-video is better, its really non-sense?

S-Video carries luminance and color on seperate cables, whereas composite cables carry both signals on the same wire. This is why svideo is a bit clearer

[MrPopo]

LoD, correct me if I'm wrong, but don't the RCA -> S-video converters not actually do anything other than as a plug adapter? Once you compress the data onto the single RCA wire you cannot re-split it out and get the same fidelity than if they came out like that from the start. At least, that's my understanding.

[dlmvii]

LoD, correct me if I'm wrong, but don't the RCA -> S-video converters not actually do anything other than as a plug adapter? Once you compress the data onto the single RCA wire you cannot re-split it out and get the same fidelity than if they came out like that from the start. At least, that's my understanding.

I'm no Duct Lord, but no, any converter like that wouldnt give any increase in signal quality.
A chain is only as good as its weakest link, as they say

[vash23n]

This could be a real breakthrough. I was never really sure how s-video worked, I just knew that my TV didn't have it. My switch boxes have s-video inputs, maybe if I plug my consoles into the s-video inputs the picture will improve. Of course, my TV is so terrible that it will still most likely look like red, yellow, and white RCA cables, which pretty much look like coaxial.

[lordofduct]

conversion is possible, it doesn't mean quality is maintained... and it definitely isn't increased.

Even though you can use a very basic adapter to split the regular RCA video cable into an S-vid cable (the process is pretty simply you just split the two frequencies apart as luminance and chrominance run at different frequencies... they have to so they can be placed on the same wire in RCA and RF cables). When you convert RCA to S-vid you don't get S-vid quality because as already mentioned, quality is as good as your weakest link. But the signal is the same exact signal.

And in actuality the conversion induces some minor degredation in quality.

RF, RCA Composite, and S-vid all use the same method of video encoding. It is stored in the YUV colour scale, the chrominance and luminance exist at two different spaces in the signal. When we include audio we gain a total of 4 signals that exist in 4 distinct frequency ranges.

All of them can potentially be mixed together into one signal making RF.

RCA composite was a step made to get the audio out of the video signal as the audio tended to bleed into the video... causing strange pulsations and static caused by the audio. Ever notice when watching antenna television from a bad signal (usually it was Fox for me) that loud noises caused the yellows to flare up??? Yeah that's the bleeding.

S-vid was a further step of breaking up all 4 signals into their own cables to further conserve quality. It stopped bleeding between everything.

Component on the other goes another step further... it took the chrominance (the colour) from the signal and split it into two parts... creating a signal that kinda resembles RGB (not the same though as the signal is still in the YUV colour space... but it applied some of the ideas about converting between the two). Here in the US we chose to stick with this YUV colour space method because most televisions were designed to be YUV natively. This is because by staying in the YUV colour space you had to distinct signals, chrominance is the colour info, and luminance is the brightness. For a B&W tv to display this signal it just ignored the chrominance signal. Thusly one of the MANY steps allowing NTSC standard to remain backwards compatable with B&W televisions (of course other things had to be kept in mind, like the 59.96hz frequency of NTSC standard video)

Anyways what they did was dedicated one wire to the Luminance (brightness, or black&white), this is the green wire. Then they describe the red as red - luminance, and blue as blue - luminance. Then you could easily construct the chrominance by adding these signals back to the luminance to get your green value.



A switch box in general will also introduce loss in quality. Many will cause bleeding of lines, signal interference, grounding issues and all kinds of stuff. Don't be surprised if little analogue artifacts show up when using them.

If you want quality video handling, you should be using a quality video processor like those found in A/V receivers which uses much better conversion methods. Especially dedicated digital video processors which quickly convert the analogue signals to digital in the A/DAC and treats them as digital there on out preserving quality through conversion steps.

Keep in mind NO CONVERSION IS LOSSLESS. Especially in analogue. Every new member you add to a chain with create loss. The plus side in digital in the matter of lossiness is that digital only suffers at conversion/scaling steps (conversion is kind of a broad term), where as analogue suffers at every step (conversion, scaling, amplification, splitting, etc).

Some might contest though then that A/V receivers are bad ideas as it is adding a new chain to the link. But as I said before, A/V receivers have quality video processors... usually better then your televisions. So by utilizing them and then outputting the signal at your TVs native settings actually helps more (of course this is a matter of outputting from the receiver in your TVs native settings... so there is no more further conversion).



Oh and while I'm at it, I want to squash a rumour I've been reading around the forums lately. RGB SCART -> YUV COMPONENT is still lossy, the process is very simple and can be done with a simple series of inverters and multipliers, it still introduces loss. Especially in the minimalist conversion which depends on splitting the Luminance of the component line and doubling the remainder back to normal.

[nateup2]

LoD, correct me if I'm wrong, but don't the RCA -> S-video converters not actually do anything other than as a plug adapter? Once you compress the data onto the single RCA wire you cannot re-split it out and get the same fidelity than if they came out like that from the start. At least, that's my understanding.

Exactly right, and pretty much all of these long-winded posts that may appear to explain otherwise were really pointless and misleading.

The signal is only as strong as its weakest link. Simple as that

Didnt realize this was a bit old. Sorry if this is considered a resurrection.

...Well, no I dont think I am sorry afterall.