Posted by Mark & Mary Ann Weiss on 07/18/07 04:41

"Smarty" <nobody@nobody.com> wrote in message
news:5eCdneQdt_lLVw7bnZ2dnUVZ_gidnZ2d@adelphia.com...
> Mark,
>
> HDV's 25 MBit/sec MPEG-2 is substantially better than the rate used for
> delivering virtually all HD content to the home, and is ***NOT*** the
> culprit. Overloaded codecs, flash A to D converters which take too long to
> settle, and DSP algorithms which don't have enough processor bandwidth are
> among the cost-saving measures used in some camcorders which create the
> erroneous observation that the HDV format somehow is at fault.

Granted, different CODECs handle the compression task with a variety of
tradeoffs, some more visible to some people than others.
But the problem here is that while 25mb/s was "acceptable" for a 345,000
pixel SD video image, the idea of shoving four times as much information
into a stream of the same bandwidth is inviting a big decrease in image
quality by the drastic increase in quantizing errors. Now granted CODEC
technology is improving steadily, but I think HDV is an overly big leap. HD
content to the home is not what I call HD. It is garbage. Every time I see
so-called "HD content" in the big box stores on plasma and LCD displays, all
I see is macroblocks--invariably, the fools who program these channels in
the stores always seem to have high-action footage running, which
exacerbates the problem. Seeing such video, if I did not know better, I
would never have bought an HDTV. Of course HDV is a hundred times
better-looking than that, but unlike DV, it has rather blatently-intrusive
visual artifacts that I can't ignore. I could watch DV footage and rarely
see an artifact that bothered me, but these HDV cams remind me of the first
DVD that I made, with shareware MPEG compression software--in short, it
looked like garbage.


> Blind, deaf, and bribed people being paid to overlook artifacts, as you
> state, is really an even more unfair indictment.

I don't think so. There are a number of people who don't think that there is
a problem with the HVR-V1U audio response. That it's not even flat within
the speech range is of no import to these people.


> The reality of the matter is that HDV video with 25 MB/sec video need not
> show any visible artifacts ***IF** the real-time encoder has enough
> horsepower. I will fully admit that many HDV camcorders, perhaps most of
> them, are marginal in this regard, and can indeed be stressed to show this
> flaw in some circumstances.

Another factor in this is how much high frequency detail is coming off the
chip block. If the imager is not resolving a lot of detail, then the coder
doesn't work as hard and quality of image goes up as quantizing error goes
down. Given a sharp imager and lots of HF detail, coder stress occurs to a
great extent and picture quality suffers.

I have both the Canon HV20 and two Sony V1Us. The former produces a soft
picture and the HDV has fewer artifacts. The Sony produces an almost
razor-sharp image, and things like individual blades of grass resolve and
that just overloads the CODEC to the point where "shimmering" artifacts
appear as the camera pans across a football field, for example. This
happened in one of my outdoor shots with the V1U, whereas to a lesser extent
with the HV20, as it didn't resolve individual blades of grass.
I think it's hard to pin the problem on the CODEC without using the same
CODEC to take the output from two different camera heads. One could
erroneously observe that Canon has a better CODEC, when in fact, it has only
less work to do, due to the integration effect on the picture signal.


> I can also list countless examples of practical limitations which exist to
> driving a Ferrari, serving a $10,000 bottle of champagne, or owning a
$7200
> Rolex. My point is that we as engineers are *****always***** trading
> performance and cost, and that HDV was, is, and will continue to be a
format
> designed and engineered very deliberately for low cost consumer and
> "prosumer" markets.

Yes, but isn't HDV supposed to be on the same playing field as DV? DV had
far fewer artifacts, yet it was a consumer format. HDV is loaded with
artifacts, and is also a consumer format, but being used in some pro
applications.


> It should not take a brilliant insight to realize that Sony and others
make
> very deliberate market segmentation decisions when choosing whether to
make
> a $2000 consumer HDV camcorder work as well or as poorly as it does.

That they do. But at what point does one draw the line between consumer and
pro? At $103,000 for an HDW-F900? It seems most of what Sony offers below
that is consumer quality.


> I think it is comical therefore to waste a lot of your breath on how poor
> HDV is, and especially to falsely conflate and confuse specific camera
> defects with the HDV format in general.
>
> Smarty

I agree that is IS a waste, but we tend to enjoy debating the pros and cons
of each formate, do we not? Lest we'd be elswhere than sitting at these PCs
and typing messages back and forth on USEnet. :-)





Best Regards,



Mark A. Weiss, P.E.
www.mwcomms.com
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