RE: TV Messenger

["Ward, David" <David.Ward@xxxxxxx>]

Thanks,  I forgot about your guide :-)

So, It would'nt be too hard to put OSD in via a RGBS or Y-C connection 
A quick and 'dirty' way I've used in the past is to basically 'tug' the
video signal with a transistor (effectively changing the termination)
to
superimpose text without affecting rest of the signal.


-----Original Message-----
From: Keith Doxey [mailto:ukha@xxxxxxx]
Sent: Tuesday, November 12, 2002 11:25 AM
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] TV Messenger


You can overlay it on the "Y" signal of S-Video or Component
Video as they
both contain Sync and Luminance (Black and White Picture) information
however you may need to increase the length of the C (S-video Chroma)
or
Cr,Cb (Component colour difference) signals to ensure that all signals
travel the same distance otherwise the colour content of the picture
will
slip left or right of the black and white content.

RGB as the term is commonly used, is actually RGBS with a composite
sync.
PC output VGA/SVGA/XGA etc, is RGBHV with separate sync.

What you refer to is RGsB or SOG as output by Sun Workstations and the
like.

http://www.kat5.tv/videoformats.html
<http://www.kat5.tv/videoformats.html>

Keith

www.diyha.co.uk
www.kat5.tv


-----Original Message-----
From: Ward, David [mailto:David.Ward@xxxxxxx]

If your signal was RGB or SVideo could you not bung the overlay signal
in
via Green or Luminance respectively.
I'm pretty sure the sync is still on Green in an RGB signal? Or is that
onlt
PCs?

Dave



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