[MPlayer-DOCS] [PATCH] update the mencoder telecine docs

Corey Hickey bugfood-ml at fatooh.org
Wed Mar 2 02:14:30 CET 2005


D Richard Felker III wrote:

> 
> My understanding is that 60000/1001 is just the only rational number
> within the range of tolerance of the NTSC refresh clock, without
> having a ridiculously huge denominator. Thus it was standardized as
> the "official" refresh for NTSC with the advent of digital video.
> 30000/1001 and 24000/1001 are just the refresh converted from fields
> to field-pairs or telecined frames.
> 
> I'm sure you can find better references on this somewhere if you
> like...
> 
> Rich
> 

Hmm. That makes sense. So, I understand the number now, but I still
don't know why a different number had to be chosen. What was wrong with
60/1, 30/1, and 24/1?

I've searched google several more times and still haven't found out why.
I have a few links that come close.

This page says it's a stupid hack:
http://homepage.mac.com/rnc/PulldownSync.html

This page says "don't ask":
http://stream.uen.org/medsol/digvid/html/3B_videoframerate.html

This page looks promising but doesn't seem to explain it:
http://www.ntsc-tv.com/ntsc-main-01.htm

That last one does list a few books that at least _ought_ to. I might
have to go to the library and see if I can find them.

-Corey




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