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View Full Version : How did 16:9 get chosen for HDTV


BwanaBob
04-20-2004, 11:26 AM
I perused all the older threads on this, but no one seems to answer my question.

Since so many movies are shot in 2.35:1 or 1.85:1, why did they choose
1.77:1 (aka 16:9)?

Personally, I'd rather have had a 2.35:1 screen and have small bars on the left
and right for other movies than still have smaller letterboxing when I watch
a 2.35:1 movie on my HDTV.

So, anyone know why this was picked?

Will Repair
04-20-2004, 12:51 PM
Went Googling for "16:9 aspect ratio reason ATSC" and got many reasons.

BwanaBob
04-20-2004, 01:17 PM
I googled as you suggested and got nothing satisfactory.

Best answer was because that's Japan's HDTV aspect ratio. Soooo-
this begs asking, why did Japan choose this?

One site implied that it was a compromise between 4:3 and 2.35:1.

What the fuck for? In a few years time - nothing will be shot in 4:3, so why
care if old TVs shows will have the grey boxes on left/right.

They should have at least gone to 1.85:1 since that indeed seems to be the
ratio used by most films.

Bytegeist
04-20-2004, 01:19 PM
It seems to have been a compromise between movie makers and television engineers. There's a brief summary of the history of this decision at least as it played out in the United States both here (http://www.fcc.gov/Bureaus/Mass_Media/Notices/fcc96207.txt) and here (ftp://www.fcc.gov/pub/Bureaus/Mass_Media/Orders/1996/fcc96493.txt). In particular I found the following:


51. There also has been objection from cinematographers to the 16:9 aspect ratio contained in the ATSC DTV Standard. They are concerned that the proposed Standard may limit broadcasters' ability to display the full artistic quality of their work. The American Society of Cinematographers has expressed the belief that the 16:9 ratio would leave digital television unable "to properly display a large portion of the largest existing library of programming." It suggests, instead, that HDTV be displayed in a 2:1 aspect ratio. That standard "would allow previous material to be faithfully displayed in its original aspect ratio with insignificant letterboxing" and is attractive to cinematographers for future feature and High Definition production.

52. In reply, the Society of Motion Picture and Television Engineers (SMPTE) states that the 16:9 aspect ratio was established by the SMPTE Working Group on High Definition Electronic Production in 1985 on the basis of studies of the requirement for both motion picture and television production. All meetings of the group, SMPTE notes, were open and well publicized. Moreover, it states that the value of 16:9 for aspect ratio was decided upon only after long debate and that "due consideration was given to the then current practices both in North America and around the world." That aspect ratio, it continues, has been adopted internationally in the International Telecommunications Union for HDTV and for EDTV in Europe and Japan. SMPTE states that it has been demonstrated that there is no difficulty in accommodating program material or motion picture films of any reasonable aspect ratio within the 16:9 format either for production and post-production, distribution or display. Material originally composed for a 2:1 aspect ratio, it continues, could be accommodated by leaving 11% of the vertical space unused.

My googling (admittedly brief) did not turn up a reason why the particular exact ratio of 16:9 was chosen. It might be because it has a nice relationship with the legacy ratio of 4:3. Namely, cropping/letterboxing between the two formats results in a simple fraction of the screen (one-third or one-fourth) being omitted or padded with black.

Bytegeist
04-20-2004, 01:28 PM
This (http://www.tvtechnology.com/features/Tech-Corner/f_technology_corner.shtml) also sheds a little light:

The earliest commercial HDTV format, the Japanese Hi-Vision system, originally had an aspect ratio of 15:9 (1.67). It was subsequently agreed, based on work that was probably originally done at RCA Laboratories in the early 1980s, that the ratio of 16:9 (1.78) was a better choice, as it is directly scaled from 4:3 by squaring that ratio. To date, the 16:9 aspect ratio is still the only HDTV standard that is agreed upon throughout the world, being standardized by the International Telecommunications Union. The ITU also amended Recommendation 601, the component digital standard for standard-definition video, to include the 16:9 aspect ratio.