avfilter: add deband filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 348e8d7e90..1035e92f77 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3878,6 +3878,43 @@ Violent denoise using a block size of @code{16x16}:
 dctdnoiz=15:n=4
 @end example
 
+@section deband
+
+Remove banding artifacts from input video.
+It works by replacing banded pixels with average value of referenced pixels.
+
+The filter accepts the following options:
+
+@table @option
+@item 1thr
+@item 2thr
+@item 3thr
+@item 4thr
+Set banding detection threshold for each plane. Default is 0.02.
+Valid range is 0.00003 to 0.5.
+If difference between current pixel and reference pixel is less than threshold,
+it will be considered as banded.
+
+@item range, r
+Banding detection range in pixels. Default is 16. If positive, random number
+in range 0 to set value will be used. If negative, exact absolute value
+will be used.
+The range defines square of four pixels around current pixel.
+
+@item direction, d
+Set direction in radians from which four pixel will be compared. If positive,
+random direction from 0 to set direction will be picked. If negative, exact of
+absolute value will be picked. For example direction 0, -PI or -2*PI radians
+will pick only pixels on same row and -PI/2 will pick only pixels on same
+column.
+
+@item blur
+If enabled, current pixel is compared with average value of all four
+surrounding pixels. The default is enabled. If disabled current pixel is
+compared with all four surrounding pixels. The pixel is considered banded
+if only all four differences with surrounding pixels are less than threshold.
+@end table
+
 @anchor{decimate}
 @section decimate