[FFmpeg-devel] [PATCH]doc: Improve fieldmatch documentation

[Carl Eugen Hoyos]

Nicholas Robbins <nickrobbins-at-yahoo.com <at> ffmpeg.org> writes:

> Do you have a sample where dejudder used like this helps?

http://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket3968/

> If so does it work better with larger n?

I didn't test because it works fine afaict.

> Your suggestion is for material that is a mix of 30 fps 
> progressive and 24->30 telecined? I don't know that you 
> would want to decimate that. It will produce judder 
> from the dropped frames. That might be a usecase for 
> the new framerate filter.

I don't have such a sample but since the fieldmatch - 
decimate combination would not support it (it only makes 
sense for 24 fps output), I don't think it has any 
relevance for the fieldmatch documentation.

> Or are you offering a suggestion for mixed 24fps 
> progressive and 24->30 telecined?

Yes.

> In that case it seems like this should work. 

This is what my tests showed.
(But I don't have a long sample.)

> You are using dejudder & fps to produce a stream of 
> frames lies ABCDDEFGHH... then decimate drops the 
> dups. Seems brutal. 

Why / how?

> Is there a reason why this filter chain is preferable 
> to pullup,dejudder? (perhaps with fps) or is this 
> just another option?

pullup is a faster alternative that may not produce 
perfect output, I don't think it works (or can be used) 
with the fps filter (that I consider being broken or at 
least showing unexpected behaviour.

Carl Eugen