[FFmpeg-user] Reversing PAL->NTSC telecining.

[Carl Eugen Hoyos]

Nicholas Robbins <nickrobbins <at> yahoo.com> writes:

> The video contains a pattern of 3 progressive and 3 interlaced 
> frames. If we think of fields it is something like this:
> 
> ZA AA BB CC CD DE EF 
> 
> Where Z is from the previous batch of 5 original frames and F 
> is from the next. This turns 5 frames into 6. Hence it was 
> used to convert from PAL (~25fps) to NTSC (~30fps.) 

> How do I undo this?

Both the fieldmatch and the pullup filter were generally able 
to inverse telecine such a sample.
Note that if the video was deinterlaced before telecined (that 
is the case for the one sample I tested so far), results will 
not be perfect, it is possible that the fieldmatch filter 
produces worse results in such a case.
(It is generally assumed to be a generation ahead of the pullup 
filter although I still didn't see a sample that shows this.)

Carl Eugen