[opendtv] Re: "we'll forever be stuck with by going ATSC"
- From: "John Shutt" <shuttj@xxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 12 Jan 2005 13:04:42 -0500
Well, no, I guess I don't (he said sheepishly.)
My basic understanding is that images start in a camera as RGB, get
converted to component for compression and storage (4:2:2, 4:1:1, or 3:1:1
depending on tape format), and final distribution (usually 4:2:0), then
ultimately gets returned to RGB in the display.
I'm having a hard time understanding how conveying the above material in RGB
from STB to a display is any different than conveying it in component from
STB to display, and have the display convert internally from component to
RGB for viewing.
I see how you can manipulate the numeric values of component to create a
negative value of RGB, but how does a camera produce a negative value of
RGB? (Does light shoot out of the CCD?) How does a CRT, LCD, or Plasma set
display a negative value of RGB (does the room get darker?)
There are values of RGB that are mathematically possible but make illegal
NTSC, therefore are illegal in CGI work destined for that medium. Wouldn't
values of component that result in negative values of RGB be equally
possible, but just as illegal and therefore avoided in CGI work?
If RGB is an unacceptable way to convey information from STB to display,
then I don't know how I'm going to break the news to my equipment, since I'm
using SVGA RGB between my Samsung STB and my Sharp LCD projector. It ain't
SCART, but it's all we Americans have.
More edumacation on my part is in order.
Regards,
John Shutt
----- Original Message -----
From: "Tom McMahon" <TLM@xxxxxxxxxx>
> Do you mean that you don't understand that legal values of Y Cb and Cr
> create negative values of R, G and B?
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