[MPlayer-users] changing fps

[Corey Hickey]

>>Can I hope in good results ?
> 
> no
> 
The problem is that you have to drop 5 frames in 30, or 1 in 6. Whenever 
one frame among several is discarded, the motion jumps. Movement between
frames would thus be smooth-smooth-smooth-smooth-smooth-JUMP-smooth-
smooth-smooth-smooth-smooth-JUMP, etc.

Go ahead and try it:
mencoder movie.avi -allyourotheroptions -ofps 25
...but don't expect anything great.

The only way you could get even motion by "down-rating" a 30fps movie
would be by going to 15fps. ...or 7.5fps, or 3.75, or... :>)

-Corey