#WFM V-Scope Techniques
07-Feb-95 22:32:26
Sb: #2685-#WFM V-Scope Techniques
Fm: Wayne Cole 76370,621
To: Steve Bennett/SYSOP 76702,1071
John,
Your confusion on the Pluge is the root of my argument: Not all RGB programs
have the same 'precision' and the mechanisms and algorithms of transfer from
video to RGB encoding are largely manufacturer dependent. So if you REALLY
wanted the correct comparison, run the Pinnacle into a Toaster, run another
Toaster into a Toaster and capture both source's bars in TPaint then look at
the RGB values. Or, if you prefer the more expensive route run one Toaster and
one Pinnacle into another Pinnacle and capture the bars from both sources in
the Switching pinnacle….
You could drive yourself nuts trying to justify the RGB's of two manufactures
products compared in different paint programs. Especially in the case of
ToasterPaint. (I forget which, but it is actually only 12 or 18 bits of color
information which is why you probably didn't see the full Pluge). One problem
with Toatster paint is in trying to do the RGB to NTSC two-step, they use a
dithering pattern that, if sampled even two pixels appart often gives different
color values eventhough it looks the same on the monitor.
Anyway, early color TV engineers probaly went thru the same thing you did –
when is red red enough and that is how the whole WavformVScope thing came
about. They basically said, "to heck with what you feed it, or how you mix it
up, just make it come out the program spigot at x IRE and y phase if its color
a." Then they divised proc amps to "teach the test".
wmc – via Autopilot!