[FFmpeg-user] Problem trying to convert PAL file to NTSC

[Thomas Worth]

On Sat, Mar 19, 2011 at 10:23 AM, Andy Civil <andycivil at gmail.com> wrote:
> Even if you succeed, you may be disappointed; FFmpeg doesn't do anything
> remotely clever to increase the frame rate.
>
> The best converters will do some motion tweening to create intermediate
> frames. The simpler converters will simply blend adjoining frames in the
> right proportion, which perfects smoothness at the expense of some blurring
> of motion. All FFmpeg does is to duplicate frames, which results in jerky
> stuttered motion.
>
> But then... in a world where some people consider Telecine Judder
> <http://en.wikipedia.org/wiki/Telecine#Telecine_judder>
> to be acceptable, maybe you won't notice <sigh>.

That's assuming the content really is 50 fields. In the case of a
dramatic feature / movie, even though it's technically 50i, it could
be from a 25p source and transferred 50i via "25psf." If this is the
case, an NTSC transfer can be done almost perfectly using 1:1 mapping
and 3:2 pulldown along with an audio time stretch.

If it's indeed 50i, then it's a little more challenging. You'll need
some software to "make up" frames to fill 60i. Something that uses an
optical flow-based retimer would be best. Adobe After Effects can do
this.