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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 21st Jan 2019, 4:43 pm   #21
John123
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Default Re: RGB signals from a VCR

Perhaps it's only outputting teletext over RGB so that it's easier to read. The text can look quite muted and colourless over composite.

ISTR a Philippe Starck designed Ferguson/Thomson machine that would output its OSD menus over RGB. I vaguely recall it having a rather odd looking trackball style remote.
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Old 21st Jan 2019, 6:23 pm   #22
mhennessy
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Default Re: RGB signals from a VCR

No, the VR716 doesn't have anything connected to the RGB pins according to the manual I'm looking at. Perhaps later versions did? I certainly agree that text would look much, much better if they had used RGB.

The Philips VR813 has an internal PAL decoder, and that contains the switches to go between off-air and teletext.

If you want to do it without an internal PAL decoder, you would have to rely on pin 16 (fast switching) to correctly do what it's meant to do (especially in "mix" and time or subtitle modes), and given that Scart standards weren't always properly followed, there would have been some risk with that.

So perhaps it was just safer (not to mention marginally cheaper) to not bother with RGB at all. I imagine that outside of the likes of us, relatively few would complain about the picture quality of the text display.

My original statement ("I guess it's possible that some of the teletext-equipped model did") is looking reasonably accurate so far, in that one definitely did (VR813), but several others did not. Until earlier today I did not know for sure whether the Grundig that we used to have outputted RGB, but now we know it didn't... Either way, ignoring pass-through, RGB is an extremely rare thing to find on a domestic VHS machine, and it won't do anything for the picture quality from tapes recorded from composite sources.

But having read about it, I would love to see a VR813 in the flesh one day
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Old 22nd Jan 2019, 12:51 am   #23
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Default Re: RGB signals from a VCR

Quote:
Originally Posted by John123 View Post
ISTR a Philippe Starck designed Ferguson/Thomson machine that would output its OSD menus over RGB. I vaguely recall it having a rather odd looking trackball style remote.
The aforementioned Thomson DVH-8090 does this (using RGB for its OSD). Even when the video output was set to composite... which is a bit of a nuisance: the TV will switch back-and-forth between composite and RGB every time one pressed 'info' or 'menu'.

Its remote control was, indeed, signed by Starck.
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Old 22nd Jan 2019, 10:43 pm   #24
John123
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Default Re: RGB signals from a VCR

That's the one! Also recall a Ferguson branded VHS only deck, which was dark grey in colour. I have a picture of in an old copy of 'What TV & Video: Book of Tests'.

Demonstration video of the VR813 in action here.
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Old 24th Jan 2019, 3:20 pm   #25
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Default Re: RGB signals from a VCR

Philips VR-969 has Composite / S-Video / RGB out selectable. I'm using it in RGB mode now and it works fine.
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Old 24th Jan 2019, 4:34 pm   #26
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Default Re: RGB signals from a VCR

Add to say the manual states "If you have connected a playback unit with separate RGB outputs, then select the "RGB" display." So specifically mentioned.
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Old 25th Jan 2019, 1:57 pm   #27
mhennessy
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Default Re: RGB signals from a VCR

Another complex beast from Philps!

I'm studying the manual in my spare moments - it's not the easiest to follow. But it appears to do some interesting things:

It appears that all the signal switching is in the YC domain - makes sense as it's easier to switch 2 signals rather than 3 or 4, and the difference in quality will be minimal, of course.

The block diagram shows the RGB pins of the two Scarts are joined to allow passthrough. There are switches that can open up to break that. When that is the case, then nothing comes out of Scart 1's RGB pins.

I note that RGB from Scart 2 travels to a PAL encoder, which turns the signal into YC.

So it looks like the passthrough is intended for an external decoder that might output RGB, connected to Scart 2.

Next, I note that the output from the teletext character generator is immediately into a PAL encoder - the output is again YC and the RGB signals go nowhere else. So it appears that you have the choice of viewing teletext in composite or S-video. If the latter, it is fairly close to RGB in terms of performance, of course.

I apologise if any of that is wrong - as I say, it's not the easiest manual to follow without printing out and sticking together - and it covers several different models. But as far as I can tell so far, the RGB from Scart 1 comes from Scart 2 only. Certainly not from playback or the teletext decoder. As I say, I could be wrong
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Old 26th Jan 2019, 12:59 pm   #28
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Default Re: RGB signals from a VCR

On the continent, pay-TV decoders were common. These accepted a scrambled picture via the composite input, worked their chop-and-swap magic and emitted the unscrambled picture as RGB (only, with just synchronising pulses on the composite output). Even if you recorded a movie, you needed the decoder to watch it as the decoding was done at playback time; and most consumer-grade VCRs could not record an RGB signal, so it was cheaper to rent the decoder than to try to pirate films.

The first analogue Sky boxes were designed to work with an external Videocrypt decoder, on the same principle: scrambled picture sent to decoder as composite, clear picture returned as RGB over same SCART connection. But then it was converted back to composite and RF by the Sky box, so recordings were made "in the clear".
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