Merge commit '7a76c6c4df31d1ff65464ccf3171acd57ef004eb'

[ffmpeg] / doc / filters.texi

diff --git a/doc/filters.texi b/doc/filters.texi
index 0c72145d80c6f45fda4ea71961c07bccf458ba19..dbcd3911ae8ecc6cb7a13b659e1e5c3ad551fd67 100644 (file)
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3486,7 +3486,7 @@ Set number overlapping pixels for each block. Since the filter can be slow, you
 may want to reduce this value, at the cost of a less effective filter and the
 risk of various artefacts.
 
-If the overlapping value doesn't allow to process the whole input width or
+If the overlapping value doesn't permit processing the whole input width or
 height, a warning will be displayed and according borders won't be denoised.
 
 Default value is @var{blocksize}-1, which is the best possible setting.
@@ -4538,7 +4538,8 @@ The number of seconds for which the fade effect has to last. At the end of the
 fade-in effect the output video will have the same intensity as the input video,
 at the end of the fade-out transition the output video will be filled with the
 selected @option{color}.
-If both duration and nb_frames are specified, duration is used. Default is 0.
+If both duration and nb_frames are specified, duration is used. Default is 0
+(nb_frames is used by default).
 
 @item color, c
 Specify the color of the fade. Default is "black".
@@ -4591,6 +4592,67 @@ fade=t=in:st=5.5:d=0.5
 
 @end itemize
 
+@section fftfilt
+Apply arbitrary expressions to samples in frequency domain
+
+@table @option
+@item dc_Y
+Adjust the dc value (gain) of the luma plane of the image. The filter
+accepts an integer value in range @code{0} to @code{1000}. The default
+value is set to @code{0}.
+
+@item dc_U
+Adjust the dc value (gain) of the 1st chroma plane of the image. The
+filter accepts an integer value in range @code{0} to @code{1000}. The
+default value is set to @code{0}.
+
+@item dc_V
+Adjust the dc value (gain) of the 2nd chroma plane of the image. The
+filter accepts an integer value in range @code{0} to @code{1000}. The
+default value is set to @code{0}.
+
+@item weight_Y
+Set the frequency domain weight expression for the luma plane.
+
+@item weight_U
+Set the frequency domain weight expression for the 1st chroma plane.
+
+@item weight_V
+Set the frequency domain weight expression for the 2nd chroma plane.
+
+The filter accepts the following variables:
+@item X
+@item Y
+The coordinates of the current sample.
+
+@item W
+@item H
+The width and height of the image.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+High-pass:
+@example
+fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
+@end example
+
+@item
+Low-pass:
+@example
+fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
+@end example
+
+@item
+Sharpen:
+@example
+fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
+@end example
+
+@end itemize
+
 @section field
 
 Extract a single field from an interlaced image using stride