🚀 go-pugleaf

In article <Bxn4Jt.K2p@rahul.net>, jonathan@rahul.net (Jonathan Heiliger) writes:
> In article <1992Nov12.190043.1@mars.slu.edu> jesse@mars.slu.edu writes:
>
>>What is the resolution of normal NTSC TVs?
>
>    NTSC is an analog format with a total of 525 lines.  However only 485 lines
> are active.  The most universal is about 648x485 pixels;

Most video digitizers I've come across seem to prefer to give you 640*480
resolution when grabbing frames from an NTSC source. I guess they're just
rounding it to a more convenient number. Or perhaps there's some standard
allowance in there for overscan.

> and NTSC cycles at approximately 59.94Hz.

I heard that the original black-and-white NTSC was 60Hz, and that the frame
rate was lowered slightly to accommodate the colour signal--probably a question
of avoiding interference between integer multiples of different frequencies.

Lawrence D'Oliveiro                       fone: +64-7-856-2889
Computer Services Dept                     fax: +64-7-838-4066
University of Waikato            electric mail: ldo@waikato.ac.nz
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