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

[Nicholas Robbins]

> On Sunday, January 5, 2014 11:48 AM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:

> > 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
> 

Thanks for the quick reply. Should I add decimate to the end? If it drops every 5th frame, it won't be doing the right thing, or will decimate=cycle=6 do what I want? Perhaps mpdecimate? Here is my first guess:

-vf "fps=fps=30000/1001,fieldmatch,decimate=6,yadif=deint=interlaced"

Is this what I should try?

If you recall, something about how mplayer dumps its vobs labels them as ~60fps, when they are really ~30.

-Nick