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Bob, et al,

FWIW, SMPTE RP 187 specifies a "Reference Image Lattice"
for the 1920 x 1080 production aperture, which includes a so-called
"clean aperture" of 1888 x 1062 leaving a 16 pixel/side and
9 pixel/horizontal edge margin around the production aperture.

This spec. is more about blanking than it is about safe title or safe
action areas, but overscan does not seem to be nearly the problem
currently that it was in 1960 when dramatic overscan was an unavoidable
fact of life in production receivers.

In the final analysis, safe title and safe action areas are defined by the
tolerances of the receiver products in the marketplace. Since HD has
zero market penetration to a first (and second) approximation, the specs
do not yet, in fact, exist. The specs will be determined by what the receiver
manufacturers can get away with, not by the SMTPE. The answer to your
question may become apparent at the CES show in January if enough
first-generation receivers are ordered by retailers. I would tentatively
define "enough" as a number equal to 1% of the installed base of television
sets in North America.

Bill Elswick

At 02:26 PM 11/17/99, Bob Buckner wrote:
 >Has anyone set any sort of High Definition standard for those old
 >familiar production considerations, Safe Title and Safe Action.  SMPTE
 >274M specifys a "Clean Aperture" that is slightly inside of the total
 >1920x1080 Production Aperture to account for D to A and blanking
 >tolerances, but no Safe T&A.

Thanks to Seamus O'Kane for support in 1999
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