[opendtv] Re: News: If There's a High-Definition TV in Your Future, Wait Till

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Fri, 31 Aug 2007 08:12:44 -0400

At 3:21 PM -0400 8/30/07, Manfredi, Albert E wrote:

Perhaps, but it sounds like you're implying HDTV and NTSC are similar.
Not exactly, although there may be some parallels. All I am saying is that these companies have a track record making unfavorable comparisons that do not reflect reality. 

BUT...
Not all HD is created equal. Several of the most popular cameras on the market today have less samples per line (but more lines) than the 1024 x 576 format I was talking about. The Panasonic HVX-200 has only about 960 samples per line. Most of Sony's 1080i cameras compress to 1440 samples per line for the 1920 x 1080 format.
The reality is that formats are nothing more than CONTAINERS, that can be filled with video content. You can fill them to the top or half way. What we need is high quality samples that are encoded with enough overhead to handle the peak bit rate requirements. The actual number of sample in the raster is less important than the integrity of the samples. For example, I could easily demonstrate that a good 1024 x 576 encoding at 10 Mbps could deliver significantly better pictures than a 1280 x 720 version at 10 Mbps. 



Now that we have all experienced the difference first hand, I think what
they were trying to get across "two decades ago" is easily demonstrable.
Most especially because TV sets have gotten to the size that is well
beyond what NTSC could do reasonably well. In my experience, anything
larger than even 25", for NTSC, was close to unacceptable.
Agreed. But a proper comparison would be to show Best versus best, not best versus worst. If NTSC is that bad, why not show a a grade A signal without all of the artifacts when comparing image quality. I've go no problem with a few scenes that show some of the problems with NTSC, like multipath, noise, etc. But to infer that NTSC looks like noisy garbage while showing uncompressed HD on the monitor next to it is highly misleading. The critters in Washington NEVER got to see an OTA HD transmission with compression until the 1998-99 time frame when the whole ATSC/DVD thing blew up. Up to that poin all of the demos were uncompressed HD direct to a monitor. 



There are some SD programs that are very much like NTSC sans ghost.

There are some SD programs that are very sharp, and look just about as
good as HDTV from 10' away on my 26" set.

Then there are varying degrees of HDTV, the best of which appear to be
live programs, for whatever reason. Getting up closer to the set does
not diminish their sharpness.
Live is not the issue. Video camera originated is typically much sharper than film, although many shooters are purposely trying to make 24P HD look like film using filters and low lighting levels that raise the noise floor. Ironically, noisy HD can look a lot like film grain.
At least we can agree that no all video is created equal. A friend has a high quality HD camera in addition to his HVX-200 now. For some scenes can intermix shots from both; for others the high quality lens and higher sampling resolution makes a huge difference. But the bulk of the work for the cameras to date is to shoot in HD and post in SD. OVersampling helps, even when the content is going to be squeezed down to fit through an SD pipe. 

Regards
Craig



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