[opendtv] Re: MPs back Ofcom stance on spectrum sale

Craig Birkmaier wrote:

> Still not getting it. This has nothing to do with the
> information content or the entropy in the respective images.
> All you are conveying is the limits on the frequencies that
> each format can deliver.

I'm not sure how many times I made that statement to you, Craig. Check
back and you might be amazed.

> We could also go a step further and talk about the potential
> MTF of each,

That is implicit in the same measurement. MTF conveys the bandwidth of
the lens, its capability to capture contrast as a function of spatial
separation. Which is implicit in that luminance and chrominance
bandwidth.

> THERE IS NO RATIO that can be applied, because the compression
> efficiency eiwill be impacted by the actual information content
> and entropy (the inaccuracy of the sampling and noise).

As Tom said, I postulate that nature has infinite detail. Start with a
scene with infinite detail. Capture that scene in the very best way you
can in 1080p and 720p formats, then compress each with the same
algorithm. That is when you will see the 2.25:1 ratio.

Just like digital audio, if you reduce the sampling rate when you
capture an image, you will be throwing away some of the higher frequency
detail, of which we already postulated there was an infinite amount. The
reason you must throw away that detail is that you must go through an
initial low-pass filtering stage in the A/D conversion, to prevent
aliasing. And that initial low-pass filtering process is tuned to the
sampling rate you plan to use in the next step.

So once again: start with the same scene, with more detail in it than
either format can do justice to. THEN you will understand why your
entropy arguments cancel out.

> This ratio is irrelevant.

The ratio is key, if you understand what's going on. Because it tells
you what it takes to be able to transmit 1080/60p in a channel barely
capable of coping with 720/60p.

> I'm really growing tired of the numerology arguments.

I'm growing tired of vague words used to dispute quantitative concepts.
You can't determine (or dispute) what it takes to transmit 1080/60p with
vague words, Craig. Just as you can't dispute what is involved in
designing SFNs by using vague words.

Also, there is no excuse for rudeness. None. You will note, the rudest
posts are ALWAYS wrong on this list. This has been true from day 1.
Rudeness does not mask cluelessness. Quite the opposite.

Bert
 
 
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