[FFmpeg-user] Converting a 23.98p source to 29.97i ProRes w/interlaced 3:2 pulldown?

[Mel Matsuoka]

> On Oct 26, 2015, at 9:15 AM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> 
> I believe (strongly) that what you like as output 
> framerate is not 29.97 but 30000/1001


Hi Carl,

I guess I'm looking for the "why",  rather than the "what", as far as this syntax is concerned. 

In NTSC broadcast land, 29.97 frame rate is *always* defined and referred to as just that: 29.97. No professional video tool that I'm aware of requires the user to define that frame rate with the level of precision that dividing 30000 by 1001 gives you.

And I suppose this begs the question, where do the numbers 30000 and 1001 come from to begin with?