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RE: History of 29.9



If the issue of rise and fall times on the 704 pixels ATSC formats were true
(which it is not), then why didn't they also conform to the notion of rise
and fall times for the 1920 pixel and the 1280 pixel formats.  Also the 640
pixel formats.  If the Table only accounts for rise and fall times on the
704 pixel formats then it is self-inconsistent. 

Neither the FCC nor the ATSC has any specification for rise/fall or blanking
times in the DTV era.  Not to say rise and fall times specifications aren't
important in the analog and DSP domains, it is just that they are not
relevant in the MPEG-2 transmission domain.

[There was a motion in the early days of the ATSC spec to be
retro-compatible with the 352-pixel MPEG-1 formats.  (Half rez mode.)  That
requirement was later eliminated but nobody fixed the table.  That's where
the 704 came from.]

A desire for MPEG-2 macroblock alignment between the production formats and
standards (SMPTE259M, SX, etc) and the emission domain would mean that
everyone either convert to all 704 pixel formats or all 720 pixel formats.
720 makes a lot more sense since most of us already own a fair pile of that
equipment.

Dolby's memo to the ATSC dated Dec 5th says that broadcasters should be
enabled to use full 448 Kbits/sec rate of the AC-3 specification, not the
384 Kbits/sec rate that the ATSC choose and formalized in the ATSC
specification A/53.  The ATSC has refused to consider increasing this number
to match the quality level provided by DVDs and other sources.

James - you misunderstood my point about the STBs.  Many people are making
these.  Zenith, Panasonic, RCA/Thomson, Mitsubishi, WebTV and others.   But
the existence of STBs only exacerbates some of the problems inherent in the
transition to DTV.













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