Exalted Being <
bpar...@gmail.com> writes:
I've played around with simulating the NTSC presentation of the input
signal, but rather than try to use a lookup table, I used signal
processing with digital filters for the luminance and chrominance
components of the signal. It looked pretty realistic, and I could also
"turn" the hue, saturation, brightness, and contrast knobs, just like
you would have on an old-days television set.
From what I remember, in order to make a proper lookup table, I think I
would have needed about a 10 or 11 stage bit-string (pixel string?).
This was due to the low bandwidth of the chroma filter (something like
0.5 MHz), and so the effect of adjacent pixels is "felt" for quite a few
pixels.
I'm not sure how I would try to interpret the groups of six bits below.
I think you're going to have to do some calculations.
The book, Video Demystified, discusses the NTSC encoding and decoding
process fairly clearly. Any edition of it will do. I have the third
edition. An old edition can probably be found for a low price.
The way I observed the "long"-lasting effect of one pixel on others, and
this might be wrong, but it seemed to me that both preceding and
following pixels had an effect on the color of the pixel.
I'm not sure of the state of my old code, otherwise I'd share it.
Probably the quickest thing for me to do would be to hook up a IIe to an
old NTSC color monitor I have and play around with bit patterns...
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Jerry awanderin at gmail dot com