🚀 go-pugleaf

In article <sa0KhqO00Uh7M2R25C@andrew.cmu.edu> bas+@andrew.cmu.edu (Bruce Sherwood) writes:
:
:Some of this discussion of HDTV implies that there will always be a need
:for another generation of standards with even higher resolution.  That
:isn't necessarily the case.  The human eye has limited resolution, and
:higher resolution than that in the picture is literally useless...
:
:The analogy with audio is that a CD with frequency response out to 10
:MHz would not sound better than one with frequency response out to 20
:KHz, because the human ear can't hear the higher frequencies.

Ooh!  I'll take this one, in two parts:

1) There will *always* be room for improvement in anything.

2) Your analogy with CD's is the right analogy for the wrong argument.  An
audio system with a 10MHz bandwith *will* sound better than one with a
20KHz bandwidth, because your ears *can* hear out there!  This old 20KHz
nonsense is a figure for steady-state, sinusoidal response and was generated
using WWII-era equipment.  Later experiments show some people with 40KHz
or better response to sine waves.  But even that isn't the biggie.  Human
hearing is very sensitive to the rise time on transients.  The wider the
bandwidth, the steeper the slope.  The steeper the slope, the more like
the real sound.  A MegaHertz is adequate for mid-fi, but not for the
good stuff.  Can you tell that I'm a DC-to-daylight freak?  Just remember
that *real* music isn't bandwidth limited at all!  (Ok, except by the
air between the source and your ear -- ditto for your stereo!)

The biggest bill of goods sold to the audio world in the last decade is
that CD's represent the state of the art in sound reproduction.  They
don't.  Not even close.  Practically an also-ran.  They *are* the
state of the art in marketing, and provide a wonderfully convenient
bang for the buck for low to mid-fi.  They're a good value, not the
cat's meow in fidelity.

I agree that there is a theoretical limit to our eyes' resolution, but
you must take into account things like frame rate (see ShowScan) and
image size (see Imax), not to mention the near limitless need for better
audio, which current HDTV just barely addresses.  CD's can't touch a
good analog master tape, and video of any kind is way behind big,
fast motion picture projection.

That doesn't mean I don't *want* HDTV!  Bring it on!  I'll be happier,
but never satisfied.


		--Craig
		...{ucbvax,sun}!pixar!good

		Gun control yields tyranny.