[FFmpeg-user] lenscorrection and vignette filters

Michael Koch astroelectronic at t-online.de
Wed Feb 3 08:53:16 CET 2016

Hi all,

I found a bug in the documentation of the lenscorrection filter:

It's written there "0.5 means no correction" for the coefficients k1 and 
This can't be right, or the formula is wrong. It's obvious that the 
formula makes no correction if k1=k2=0.

For positive k1 and k2, r_tgt is always smaller than r_src. That means 
in the target image there are undefined pixels at the edges. Which color 
is used to fill these pixels? There should be a "fillcolor" parameter as 
in the rotate filter.

Other question:
Which formula is used for the vignette filter?


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