lavfi: add edgedetect filter.

Changelog

@@ -47,6 +47,7 @@ version next:
 - hue filter
 - ICO muxer
 - SubRip encoder and decoder without embedded timing
+- edge detection filter
 
 
 version 0.11:

doc/filters.texi

@@ -1929,6 +1929,33 @@ For more information about libfreetype, check:
 For more information about fontconfig, check:
 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
 
+@section edgedetect
+
+Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
+
+This filter accepts the following optional named parameters:
+
+@table @option
+@item low, high
+Set low and high threshold values used by the Canny thresholding
+algorithm.
+
+The high threshold selects the "strong" edge pixels, which are then
+connected through 8-connectivity with the "weak" edge pixels selected
+by the low threshold.
+
+@var{low} and @var{high} threshold values must be choosen in the range
+[0,1], and @var{low} should be lesser or equal to @var{high}.
+
+Default value for @var{low} is @code{20/255}, and default value for @var{high}
+is @code{50/255}.
+@end table
+
+Example:
+@example
+edgedetect=low=0.1:high=0.4
+@end example
+
 @section fade
 
 Apply fade-in/out effect to input video.

libavfilter/Makefile

@@ -90,6 +90,7 @@ OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
 OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o
+OBJS-$(CONFIG_EDGEDETECT_FILTER)             += vf_edgedetect.o
 OBJS-$(CONFIG_FADE_FILTER)                   += vf_fade.o
 OBJS-$(CONFIG_FIELDORDER_FILTER)             += vf_fieldorder.o
 OBJS-$(CONFIG_FIFO_FILTER)                   += fifo.o

libavfilter/allfilters.c

@@ -81,6 +81,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (DESHAKE,     deshake,     vf);
     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);
     REGISTER_FILTER (DRAWTEXT,    drawtext,    vf);
+    REGISTER_FILTER (EDGEDETECT,  edgedetect,  vf);
     REGISTER_FILTER (FADE,        fade,        vf);
     REGISTER_FILTER (FIELDORDER,  fieldorder,  vf);
     REGISTER_FILTER (FIFO,        fifo,        vf);

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  9
-#define LIBAVFILTER_VERSION_MICRO 102
+#define LIBAVFILTER_VERSION_MINOR  10
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \

tests/lavfi-regression.sh

@@ -42,6 +42,7 @@ do_lavfi "crop_scale"         "crop=iw-100:ih-100:100:100,scale=400:-1"
 do_lavfi "crop_scale_vflip"   "null,null,crop=iw-200:ih-200:200:200,crop=iw-20:ih-20:20:20,scale=200:200,scale=250:250,vflip,vflip,null,scale=200:200,crop=iw-100:ih-100:100:100,vflip,scale=200:200,null,vflip,crop=iw-100:ih-100:100:100,null"
 do_lavfi "crop_vflip"         "crop=iw-100:ih-100:100:100,vflip"
 do_lavfi "drawbox"            "drawbox=224:24:88:72:#FF8010@0.5"
+do_lavfi "edgedetect"         "edgedetect"
 do_lavfi "fade"               "fade=in:5:15,fade=out:30:15"
 do_lavfi "null"               "null"
 do_lavfi "overlay"            "split[m],scale=88:72,pad=96:80:4:4[o2];[m]fifo[o1],[o1][o2]overlay=240:16"

tests/ref/lavfi/edgedetect

+edgedetect          16bce636eef1a82e18837d176f4187c1