Researching history of HDTV standard aspect ratio for article

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Researching history of HDTV standard aspect ratio for article

Postby cinema600 » 09 Feb 2010, 10:45

Hi guys,
I am researching when 16 x 9 was decided upon as the aspect ratio for HD tv sets and production. I vaguely remember the ASC (American Society of Cinematographers) challenging the 1.78:1 (16 x 9) aspect ratio and wanted it to be true cinema 1.85:1. This challenge by the ASC is what I'd like to research and perhaps their dispute with SMPTE over HD standards. Does anyone know where I might find this information?

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Postby akirby » 09 Feb 2010, 11:51

IF you believe wikipedia:

The IWP11/6 working party considered many views and through the 1980s served to encourage development in a number of video digital processing areas, not least conversion between the two main frame/field rates using motion vectors, which led to further developments in other areas. While a comprehensive HDTV standard was not in the end established, agreement on the aspect ratio was achieved.

Initially the existing 5:3 aspect ratio had been the main candidate, but due to the influence of widescreen cinema, the aspect ratio 16:9 (1.78) eventually emerged as being a reasonable compromise between 5:3 (1.67) and the common 1.85 widescreen cinema format. (Bob Morris explained that the 16:9 ratio was chosen as being the geometric mean of 4:3, Academy ratio, and 2.35:1, the widest cinema format in common use, in order to minimize wasted screen space when displaying content with a variety of aspect ratios.[8])

An aspect ratio of 16:9 was duly agreed at the first meeting of the IWP11/6 working party at the BBC's Research and Development establishment in Kingswood Warren. The resulting ITU-R Recommendation ITU-R BT.709-2 ("Rec. 709") includes the 16:9 aspect ratio, a specified colorimetry, and the scan modes 1080i (1,080 actively interlaced lines of resolution) and 1080p (1,080 progressively scanned lines). The current Freeview HD trials use MBAFF, which contains both progressive and interlaced content in the same encoding.

It also includes the alternative 1440×1152 HDMAC scan format. (According to some reports, a mooted 750 line (720p) format (720 progressively scanned lines) was viewed by some at the ITU as an enhanced television format rather than a true HDTV format,[9] and so was not included, although 1920×1080i and 1280×720p systems for a range of frame and field rates were defined by several US SMPTE standards.)

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Aspect ratio

Postby Dale » 09 Feb 2010, 14:19

The Japanese had decided back in the earliest days (around 1970) that 5:3 was the best Aspect Ratio, but it was David Sarnoff Research Center's "most decorated TV engineer", Dr. Kerns Powers. led the industry campaign to change it one more time from 5:3 to 16:9/ The reason: using picture-in-picture you can get 3 4:3 standard images to fit on the 16:9 screen. The ASC finally woke up at the end of the process and asked for 2:1 and while that was given some consideration by the SMPTE HD TV production committee, it was decided that the 2:1 would put too much stress upon the glass envelope (the tube) and that would be more fragile than the more squarish 16:9; At that time it was still thought that tubes would be with us for several years and anything that would produce a physical structure would impede the market-- something not desired. Had the LCD technology had more of a leadership role in the standards a much wider aspect ratio could have been conceivable. The fact that there is no STANDARD for motion picture aspect ratios no choice for TV would be perfect. So. it was decided that some "average" be chosen since there is no absolute reference upon which to anchor. The final vote on the aspect ratio was taken at a special session of the SMPTE HD Production standard group at the Motion Picture Academy's building in Hollywood. While isolated protest against 16:9 was heard in the final debate the cry was not shrill enough to warrant any change in the hardware and software already established and so it was passed by a near-unanimous verbal vote of the 80 or so in attendance. The exact dates and other information can be found in back issues of the HDTV Newsletter, something this magazine published prior to our focus changing to stimulate the HD consumers. Contact me if you would like more information along with the specific dates or you can order from us a back issue that covered this question. ($35.00).

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