1990-08-04|Don't forget aspect ratio

To the editor

• In a flurry of debates on the HDTV standards development including such fundamental parameters as the number of scanning lines and fields, interlace versus progressive scan, and even analog versus digital encoding scheme (latest General Instruments entry), no attention seems to have been paid to the aspect ratio.

• The original HDTV aspect ratio of 15:9 was drawn up by NHK (Japan Broadcasting Corporation) in the late 1970's. It was based on a series of perception tests to come up with an optimum aspect ratio by the viewers watching small-screen TV sets at a time when few large-screen projection TV sets were available, flat-screen display was only a dream, and personal computers were almost non-existent. Somehow, the ratio evolved to 16:9 in the U.S., and the entire TV industry seems to have been caught by this paradigm for a decade or so.

• This evolution resembles that of cinematography which has seen a similar aspect ratio change from the 35 mm format (7:4) to the 70 mm format (11:5). However, more recent large-format IMAX films, which few people had seen when the NHK tests were conducted, feature near 1:1 aspect ratio on a huge screen and almost covers the viewer's entire sight. Moreover, OMNIMAX films, considered to give an ultimate viewing experience, are round just like the very original TV sets! This is consistent with the natural fact that the sight field of a human being is circular.

• Even though text oriented, computer display monitor initially inherited the aspect ratio of 4:3 from the TV screen. As a result, it is very awkward for people used to letter or legal size documents to read pages on a regular computer screen, so screen formats with various aspect ratios have been devised over the years, leading to today's chaotic situation. However, high-performance engineering workstations with impressive graphics are prevailed by near-square display with up to 1 024 x 1 024 pixels.

• The North American TV industry should not follow the panic mentality of "Chasing Japan in the HDTV race" (IEEE Spectrum, October 1989), but make a logical decision based on rational thinking and common sense. The question is "What is the ideal HDTV aspect ratio for the sake of better civilisation?". I firmly believe that the natural answer is 1:1 which not only simplifies everything but also helps merge the existing TV and computer display formats, and eventually give us comfortable HDTV viewing on a large wall-mounted screen at home just as OMNIMAX films do in the theatres today.

• Here is a summary of aspect ratio on display.

  Golden Ratio	1.61803
  letter format	8.5:11 = 0.77
  legal format	8.5:14 = 0.61
  NTSC/PAL/SECAM TV	4:3 = 1.33
  original HDTV proposal	15:9 = 1.67
  current HDTV proposal	16:9 = 1.78
  35 mm film	7:4 = 1.75, 1.85
  70 mm film	11:5 = 2.20
  Imax film	10:7 = 1.43
  Imax-Dome (Omnimax) film	circular = 1.00
  computer monitor	chaos
  my proposal	1:1 = 1.00
  ultimate goal	circular = 1.00

• Thank you very much for your attention.

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"Sunatori, Go Simon" <GS.Sunatori@HyperInfo.CA>

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• 2025-01-14T20:55:02.000Z