lavfi: add colorkey_opencl filter

This is a direct port of the CPU filter.

Signed-off-by: Jarek Samic <cldfire3@gmail.com>
Signed-off-by: Mark Thompson <sw@jkqxz.net>

1 files changed, 33 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 965756c003..cfff9b1f4d 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -19103,6 +19103,39 @@ Apply erosion filter with threshold0 set to 30, threshold1 set 40, threshold2 se
 @end example
 @end itemize
 
+@section colorkey_opencl
+RGB colorspace color keying.
+
+The filter accepts the following options:
+
+@table @option
+@item color
+The color which will be replaced with transparency.
+
+@item similarity
+Similarity percentage with the key color.
+
+0.01 matches only the exact key color, while 1.0 matches everything.
+
+@item blend
+Blend percentage.
+
+0.0 makes pixels either fully transparent, or not transparent at all.
+
+Higher values result in semi-transparent pixels, with a higher transparency
+the more similar the pixels color is to the key color.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Make every semi-green pixel in the input transparent with some slight blending:
+@example
+-i INPUT -vf "hwupload, colorkey_opencl=green:0.3:0.1, hwdownload" OUTPUT
+@end example
+@end itemize
+
 @section overlay_opencl
 
 Overlay one video on top of another.