Author Topic: RGB output to Component TV input  (Read 4509 times)

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Offline redbox

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RGB output to Component TV input
« on: 15:50, 11 November 13 »
Is the RGB signal from a classic CPC (or Plus) compatible with the RGB "component" input you find on some TVs?

For example, would it be possible to create a cable like this one for the Wii?

And would the picture quality be better than via SCART (as is the case with the Wii)...?

Offline The Last Bandit

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Re: RGB output to Component TV input
« Reply #1 on: 16:11, 11 November 13 »
Nope.


RGB is a type of 'component' TV signal and YPbPr which is what those Wii cables are is another type of 'component' cable - however the two are not the same and are not compatible.


The red, green and blue colour they use on those cables is a bit misleading as they don't refer to the actually colour signals.


Quailty wise, RGB is as good as you'll get out of the Amstrad.


Offline Bryce

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Re: RGB output to Component TV input
« Reply #2 on: 16:15, 11 November 13 »
I'll try really hard to keep this short and understandable:

Component video is a complicated bunch of colour space standards, with several different variations. The most common are:

YPBPR = Analogue version - most likely to work with a CPC, but would need more than just a cable - electronics needed.
YCBCR = Digital version - more difficult for a CPC to manage and needs even more electronics.
SoG = Sony rubbish that added the Sync signal to the green signal, also known as RGSB.

Due to the fact that component video keeps things separated, the resulting picture should be slightly better than S-Video, but about equal to SCART. However, I would assume that most TVs with Component video inputs don't allow frequencies below VGA (31KHz), so a scan-doubler would be needed for it to work with the CPCs 15KHz picture.

Bryce.

Offline redbox

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Re: RGB output to Component TV input
« Reply #3 on: 16:16, 11 November 13 »
Quailty wise, RGB is as good as you'll get out of the Amstrad.

Ok thanks.

I need to make a sync stripper then :)

Offline The Last Bandit

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Re: RGB output to Component TV input
« Reply #4 on: 16:27, 11 November 13 »
What are you trying to connect the Amstrad up to ?

Offline redbox

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Re: RGB output to Component TV input
« Reply #5 on: 22:34, 11 November 13 »
What are you trying to connect the Amstrad up to ?

Just a 6128.  I already have it connected via SCART, but I get a bit of wobble now and then.   I also have a S-Video modulator so might use that.

I just noticed the Composite inputs on my TV (and remembered the Wii cable) so thought it was worth a mention as I couldn't find any information about it on the net anywhere for the CPC :)

Offline emuola

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Re: RGB output to Component TV input
« Reply #6 on: 12:40, 14 November 13 »
Ok thanks.

I need to make a sync stripper then :)


The sync stripper (Sync Strike) resolved all my problems with wobbly scart picture. The image is now rock solid and very good indeed.
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Offline dragon

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Re: RGB output to Component TV input
« Reply #7 on: 13:01, 14 November 13 »
So, adapter euroconector-> rca not work?.(the gx 4000 work). My computer monitor is a old philips 170T only rca,component, and rf.

Offline The Last Bandit

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Re: RGB output to Component TV input
« Reply #8 on: 15:07, 14 November 13 »
I don't think the CPC's output composite video so those SCART/RCA adapters won't work. 


The sync strike is probably just fixing a grounding issue with your cable than anything else.

Offline Bryce

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Re: RGB output to Component TV input
« Reply #9 on: 15:39, 14 November 13 »
A sync stripper is normally used to extract a clean, raw sync signal from a composite video (RCA / CVBS / FBAS / whatever you like to call it) signal. The CPC already provides an almost raw csync signal, so it shouldn't need one. The only effect the stripper would have is to possibly amplify the peak voltages of the sync pulses. which may help if your sync pulse isn't to the correct voltage, your connections are bad or if you decided to make a 10 metre long SCART cable. It doesn't correct the frequency, nor does it do any other secret magic that might improve the picture, so there really should be no need for it on a CPC.
As The Last Bandit stated, the CPC only outputs RGB or a pure LUM signal for green screens. It doesn't produce a composite signal.

@Dragon: Yes, the GX4000 does supply a composite signal on the SCART socket, but standard CPCs (including the Plus) don't.

Bryce.
« Last Edit: 15:43, 14 November 13 by Bryce »

Offline gerald

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Re: RGB output to Component TV input
« Reply #10 on: 18:59, 14 November 13 »
@Dragon: Yes, the GX4000 does supply a composite signal on the SCART socket, but standard CPCs (including the Plus) don't.
One exception : French GX4000 does not supply composite video signal on the SCART, only a composite sync signal.
Thanks to the removal of the RF modulator, they also removed the RGB to composite converter.
French GX4000 SCART is pure RGB, no trade-off on video quality  :laugh:

Offline Bryce

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Re: RGB output to Component TV input
« Reply #11 on: 21:31, 14 November 13 »
Interesting, didn't know that. I wonder was that due to not wanting to support SECAM?

Bryce.

Offline TFM

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Re: RGB output to Component TV input
« Reply #12 on: 22:26, 14 November 13 »
Probably not. Amstrad was always into saving money IMO.




Edit: However not of cost of functionality. My CPCs work well since 30 years nearly, there's not much hardware with that long life cycle.  :) 
« Last Edit: 22:45, 14 November 13 by TFM »
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Offline Devilmarkus

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Re: RGB output to Component TV input
« Reply #13 on: 22:28, 14 November 13 »
In France it's obligatory, that all colour TV have a RGB scart connector, so why build-in a HF modulator or something like that, when all colour-TV have a RGB connector?
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Offline gerald

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Re: RGB output to Component TV input
« Reply #14 on: 22:41, 14 November 13 »
Interesting, didn't know that. I wonder was that due to not wanting to support SECAM?

In fact, as Markus pointed, SCART (Peritel) became mandatory on all TV sold in France since1980.
So Amstrad saved on the modulator and ancillary function (like the RGB to composite)

Offline TFM

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Re: RGB output to Component TV input
« Reply #15 on: 22:43, 14 November 13 »
Ah! Learnt something new!  :)
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