lavfi: add nlmeans filter

Fixes Ticket #4910

1 files changed, 35 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 070e57d40f..7aa541f42b 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -9695,6 +9695,41 @@ Negate input video.
 It accepts an integer in input; if non-zero it negates the
 alpha component (if available). The default value in input is 0.
 
+@section nlmeans
+
+Denoise frames using Non-Local Means algorithm.
+
+Each pixel is adjusted by looking for other pixels with similar contexts. This
+context similarity is defined by comparing their surrounding patches of size
+@option{p}x@option{p}. Patches are searched in an area of @option{r}x@option{r}
+around the pixel.
+
+Note that the research area defines centers for patches, which means some
+patches will be made of pixels outside that research area.
+
+The filter accepts the following options.
+
+@table @option
+@item s
+Set denoising strength.
+
+@item p
+Set patch size.
+
+@item pc
+Same as @option{p} but for chroma planes.
+
+The default value is @var{0} and means automatic.
+
+@item r
+Set research size.
+
+@item rc
+Same as @option{r} but for chroma planes.
+
+The default value is @var{0} and means automatic.
+@end table
+
 @section nnedi
 
 Deinterlace video using neural network edge directed interpolation.