[opendtv] Re: Vizio's very wide CinemaWide 21:9 TV is a revelation for movie buffs

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Wed, 1 Aug 2012 15:27:26 -0500

Craig Birkmaier wrote:

>> 1. What displays or what display interfaces are set up to accept
>> a 21:9 anamorphic squeeze image from a BluRay disc or DTV medium,
>> presumably this would be in a 1920 X 1080 container?
>
> Who cares. These containers are intentionally crippled. h.264 and
> HDMI can easily handle 21:9 and much more.

We've had this debate countless times.

When you use analog interfaces, such as RGB or any of the TV analog display 
standards, it is critically important that you tell the STB or the PC what the 
display aspect ratio is. If you do not do so, all images to that display will 
become distorted. (For RGB, you typically give the aspect ratio in the form of 
pixels horizontal and vertical. For the others, it's almost universally either 
4:3 or 16:9, and that's it. No other options provided.)

If you buy an odd-ball shaped PC monitor, or PC monitor with oddball pixel 
configuration, the monitor *invariably* comes with a setup CD or DVD. In that 
setup disc comes whatever display drivers are needed, to get your video card to 
fill the screen correctly. BUT, such setup discs do not come with TV sets, that 
I've ever seen anyway. (Which is why I made sure, before buying the PC-STB I 
have, that the PC's video card could handle RGB to a 1366 X 768 TV set. Which 
oddly is also capable of 1360 X 768, which turned out to be the correct setting 
for the PC.)

This is an orthogonal issue to what the transmitted images to that display are 
coded for.

Now comes HDMI.

One of the supposed advantages of a digital display interface is that you 
aren't supposed to have to mess with the monitor settings. But that *has* to 
mean, somehow or other, the STB or PC and the monitor have to talk to each 
other, so that the monitor can tell the PC or STB what its aspect ratio is. 
Right? Otherwise, that PC or STB will not know how to get an image to that 
display undistorted. Things will look tall and skinny or short and fat.

So, can HDMI properly accommodate a screen whose aspect ratio is 4.38:1? Or for 
that matter 2.33:1?

The answer is, **only if** the information to that screen is sent in **4:3 or 
16:9 containers**. And then, the screen can do its own post-processing (aka 
cropping). Said another way, the display has to "pretend" to be either 4:3 or 
16:9, and that's what the PC or the STB will assume it is.

http://www.audioholics.com/education/display-formats-technology/hdmi-interface-a-beginners-guide

----------------------------------
Supported Color Space and Video Formats 
HDMI pixel encoding includes support for RGB 4:4:4 as well as digital TV's 
YCbCr 4:4:4 amd YCbCr 4:2:2 color spaces. The two 4:4:4 encoding formats are 
both 8-bit per component sampling for 24-bit per pixel delivery. The 4:2:2 
encoding format uses up to 12-bits per component for greater color depth.

HDMI can support all existing and planned PC or TV video formats. Several 
formats were specifically established in order to jump-start compatibility 
between products and media whose resolutions were different:

SDTV: 720x480i (NTSC), 720x576i (PAL) 
EDTV: 640x480p (VGA), 720x480p (NTSC progressive), 720x576p (PAL progressive) 
HDTV: 1280x720p, 1920x1080i (1920x1080p is supported but was not initially 
defined when the spec was penned) 
All SD formats are available in 4:3 as well as 16:9 aspect ratios while HD 
formats are available in the 16:9 ratio only.
----------------------------------

So bottom line: the article was incorrect when it implied that 2.33:1 video was 
sent to the TV set as an anamorphic squeeze in a 1920 X 1080 container. There 
is no such beast. The info instead *has* to be sent as linear 1920 X 1080, 
letterboxed, pillarboxed, or postage stamped. And the TV set them crops it to 
fill the 2.33:1 screen area.

Bert

 
 
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