- /* A film of F seconds at f FPS will be Ff frames;
- Consider some delta FPS d, so if we run the same
- film at (f + d) FPS it will last F(f + d) seconds.
-
- Hence the difference in length over the length of the film will
- be F(f + d) - Ff frames
- = Ff + Fd - Ff frames
- = Fd frames
- = Fd/f seconds
-
- So if we accept a difference of 1 frame, ie 1/f seconds, we can
- say that
-
- 1/f = Fd/f
- ie 1 = Fd
- ie d = 1/F
-
- So for a 3hr film, ie F = 3 * 60 * 60 = 10800, the acceptable
- FPS error is 1/F ~= 0.0001 ~= 10-e4
- */
-
- return (fabs (a - b) < 1e-4);