[opendtv] Re: TVTechnology: HPA 2015: OTT, HDR, 4K and Last Rites for 4:3

  • From: Craig Birkmaier <craig@xxxxxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 19 Feb 2015 00:59:53 -0500

On Feb 18, 2015, at 10:28 PM, Manfredi, Albert E <albert.e.manfredi@xxxxxxxxxx> 
wrote:
> 
> So, what the explanation SHOULD have been is that cable systems still need to 
> have an analog version of the content, for old dumb analog TVs?

No. For old analog head ends that use NTSC encoding. As all new TVs still 
support NTSC inputs, both old CRTs and new widescreen DTVs are using the analog 
cable service.

> Saying SD instead of "analog" is very misleading. The digital versions, SD or 
> HD, virtually never need to be 4:3 anymore, if 90 percent of households have 
> 16:9 sets anyway.

Actually they are essentially the same, as MPEG-2 MP@ML is based on the 
digitized representations of NTSC (525 line) and PAL (625 line) using 720 
samples per line for both 4:3 and 16:9 sources. 

With analog cable you have three choices:

4:3 center cut
4:3 letterbox
16:9 squeezed into 4:3 - old NTSC CRT TVs can't un-squeeze this, so it is not 
used in analog cable systems; it is commonplace with digital SD system like 
those used in Europe.

> Any DTV viewer watching SD material has no reason to be viewing it as 4:3 
> anymore. Even if he's viewing it on an old CRT via STB, at the very worst, 
> the STB can pan and scan. Or of course, letterbox.

We are not talking about DTV viewers; we are talking about analog cable in the 
U.S. And other parts of the world, as well as the analog broadcast systems 
still in use in many parts of the world.

> Not sure how this is relevant.

Most networks were opposed to using letterbox for analog systems, as it does 
not fill the 4:3 screens. Some are finally beginning to come around.
> However the wide screen presentation is restored, digital SD material need 
> not be shot as 4:3, or even protected for 4:3, JUST BECAUSE it's SD. The 
> comment from CBS was about shooting the frame, protecting the content for 
> eventual 4:3 viewing, not about transmitting it anamorphic vs postage stamp.

Exactly. The ability to extract 4:3 for many markets is still very important, 
so CBS protects the 4:3 area even when shooting wide screen HD. It does not 
matter whether you are shooting SD, HD, or UHD (4K); you still need to protect 
the 4:3 extraction.

> Anyway, I've said this before, as far as I'm concerned, broadcasters should 
> transmit all of their SD as anamorphic squeeze 16:9 these days.

Fine, if you only want that broadcast to be used by newer DTV receivers. You 
cannot use the anamorphic squeeze version to feed an analog cable system, 
although the cable head end could use a convertor that decodes the DTV 
broadcast and either extracts the 4:3 (center cut or pan and scan if used), or 
letterboxes the full 16:9 frame in 4:3.

Regards
Craig 
 
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