[Fwd: 16:9 Aspect Ratio]

[Dave Doherty]

A couple of additional points to add to Brian's excellent report...

When HDTV was developed in the 1980s (that is NOT a typo!), there were no 
blue LEDs, so LED TVs were out of the question, and LCDs were incredibly 
slow. The only practical direct-display devices were CRTs.

>From the structural viewpoint, the larger the CRT, the heavier the glass 
frontplate must be. And the rest of the glass has to be stronger as the tube 
gets less symmetrical. (Remember those early-days round CRTs in the cheap 
TVs? That's why they were made that way.) So as you make the CRTs bigger and 
wider, they get heavier, and that happens way out of proportion to the 
increase in the viewing size.  Even moderately-sized 16:9 CRTs weigh 
hundreds of pounds.

Today, of course, those factors don't carry much weight.  (ta-da!)  Screens 
can be made in any shape you want, and there will undoubtedly be many more 
choices in the future. Broadcast TV will probably stick to 16:9, but movies 
can be released in CinemaScope or even Cinerama or IMax, and you can view 
them that way if you can afford the screen.

Something that hasn't gotten much public notice is that 16:9 is 4:3 squared, 
which makes a lot of the image conversion processing math easier, and the 
following item possible:

You can display four 4:3 images simultaneously on a 16:9 display - one full 
size, and three 1/3 size images stacked on one side or the other. If you 
really wanna go nuts and you have the processing available, you can display 
a main 4:3 image and two columns of six small images each - a total of 13 
simultaneous 4:3 images - more than sufficient to satisfy even the most 
hard-core news junkie on election night!

-Dave Doherty
 Skywaves, Inc.
 97 Webster Street
 Worcester, MA 01603
 508-425-7176






----- Original Message ----- 
From: "Brian Vita" <brian_vita@cssinc.com>
To: "'Sid Schweiger'" <sid@wrko.com>; "'Boston Radio Interest'" 
<boston-radio-interest@rolinin.bostonradio.org>
Sent: Wednesday, January 23, 2008 1:42 PM
Subject: RE: [Fwd: 16:9 Aspect Ratio]


>>Who decided that the world would enjoy
16:9 aspect ratio and widescreen TV receivers?<<

>16:9 happens to be the same aspect ratio as a widescreen motion picture
(i.e., CinemaScope or PanaVision).

Aha! Finally a question where I'm the expert!

Cinema people don't refer to the picture aspect ratios in the same terms as
TV folk.  For example, we call the 4:3 ratio 1.33:1.  We call "widescreen"
(currently the flat non-anamorphic format) 1.85: and CinemaScope is actually
2.35:1.

The "widescreen" HDTV format of 16:9 would thus translate to 1.77:1.  This
is NOT the CinemaScope format.  It is slightly squarer than the standard
"flat" 1.85:1 ratio.  This would mean that most movies that are shot "flat"
would crop nicely to the HDTV 16:9 format.  Cinemascope (and its variations)
would still be letterboxed.

As a side note, CinemaScope was originally a trademark of 20th Century Fox.
When the other studios wanted to do a wide screen anamorphic process they
had to come up with their own name and "squeeze"ratio.  This created a major
problem as you now had to have a set of lenses for each studio.  There were
variable lenses with swivel prisms that could adjust the squeeze ratio but
these ate light incredibly.  The industry finally standardized on the 2.35:1

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