Date   : Mon, 25 May 2009 14:58:51 +0100
From   : me@... (me@...)
Subject: S-Video mod for Master 128

On 25 May 2009, at 11:51, Francis Devereux wrote:

>  - With the S-Video mod in place, the composite video out looks noisy
> (can anyone explain why?).

I'd imagine because the s-video cable is acting as an antenna and  
injecting RF noise into the video.

You should also be aware that this isn't "real" s-video - the quality  
of the image will be no better than a straight composite connection,  
TV post-processing notwithstanding.

All you're doing is feeding the composite colour signal into both the  
lumen and chroma inputs of the s-video cable. This will indeed result  
in "correct" colour, but it won't do anything to get rid of dot crawl  
or any other kinds of composite video artefacts.

The BBC lacks an s-video encoder so it's not possible to get "real" s- 
video out of it, unless you were to convert it from the RGB signals.  
(Which theoretically should work just fine, but such converters are  
not cheap. For example: http://www.js-technology.com/product_info.php?products_id=34

  )

The best picture quality on a TV from a beeb today is still an RGB-to- 
SCART cable.

-- 
David Glover
http://www.davidglover.org/