[FFmpeg-devel] [PATCH]Mention in the documentation that fieldmatch needs cfr input

Carl Eugen Hoyos cehoyos at ag.or.at
Sat Oct 25 14:22:15 CEST 2014

Clément Bœsch <u <at> pkh.me> writes:

> > +The filter only works for constant frame rate input. If your input
> > +has mixed telecined and progressive content with changing framerate,
> > +try the  <at> ref{pullup} filter.
> Well I don't mind much but then... how is pullup making 
> any difference here actually?

You mean why does it work with pullup but not fieldmatch? 
I honestly cannot answer, sorry...

> fieldmatch isn't actually touching the pts nor using them.

I wonder if that (together with using decimate) isn't the 
But this is of course completely unrelated.

Just to sum it up:
pullup works fine and is fast for all samples I have seen, 
it definitely misses many merging opportunities if the 
horizontal motion is very low (meaning some frames with 
artefacts remain for every real-world input).
fieldmatch is very slow, it is apparently able to 
produce perfect output for badly cut input with constant 
(telecined) framerate but it fails completely for mixed 
content (as found on many DVD's).

Imo, fps=30000/1001,fieldmatch,decimate should fix this 
but decimate unfortunately does not drop the frame that 
fps inserted but a random (?) frame.
(Or fieldmatch finds matches in progressive input?)

Carl Eugen

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