[opendtv] Re: (no subject)
- From: dan.grimes@xxxxxxxx
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 8 Dec 2009 09:24:00 -0800
"If we are really to believe that 1080/60p takes up no more channel
capacity than 720/60p, then we are also claiming that 720/60p takes up no
more channel capacity than 480/60p, and by logical extension, 1080/60p
takes up no more channel capacity than 480/60p." -Bert
Your "If A=B and B=C then A=C" logic is infallible. But your premise that
anyone thinks A=B is absurd.
Before that you say the following:
"I also wouldn't doubt that a heavily pre-filtered 1080/60p can fit in the
same channel as a 720/60p. But then again, the pre-filtered 1080/60p would
also have no more detail than the 720/60p."
Again, I agree that pre-filtering the material to render it the same as
720P is not a real gain. However, I do not think that pre-filtering is the
only way one can achieve the compression needed to get 1080/60P to the
target bit-rate. There are other ways to increase "efficiency", that is,
the ability to get better picture quality for the same bit-rate. There are
many techniques, especially the change in algorithms, that can improve
picture quality while reducing bit rate, even while using the same encoding
standard.
I think it is important to remember that all mathematics applied to the
compression are only approximations of a theoretical best transformation.
As processing power increases, the algorithms can become more complex and
the processing more accurate. This allows for an increase in efficiency
even within the same encoding standard. So if someone says we may one day
put 1080/60P within the same bit rate as previously was only able to
provide 720/60P for a given signal-to-noise ratio, they may well be
correct. And that does not take into account that better encoding
standards might be used.
Dan
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