avfilter: add sobel and prewitt filter

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

Changelog

@@ -27,6 +27,7 @@ version <next>:
 - weave filter
 - gblur filter
 - avgblur filter
+- sobel and prewitt filter
 
 
 version 3.1:

doc/filters.texi

@@ -10860,6 +10860,23 @@ Set medium thresholding (good results, default).
 @end table
 @end table
 
+@section prewitt
+Apply prewitt operator to input video stream.
+
+The filter accepts the following option:
+
+@table @option
+@item planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+@item scale
+Set value which will be multiplied with filtered result.
+
+@item delta
+Set value which will be added to filtered result.
+@end table
+
 @section psnr
 
 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
@@ -12714,6 +12731,23 @@ asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
 @end example
 @end itemize
 
+@section sobel
+Apply sobel operator to input video stream.
+
+The filter accepts the following option:
+
+@table @option
+@item planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value 0xf, all planes will be processed.
+
+@item scale
+Set value which will be multiplied with filtered result.
+
+@item delta
+Set value which will be added to filtered result.
+@end table
+
 @anchor{spp}
 @section spp
 

libavfilter/Makefile

@@ -238,6 +238,7 @@ OBJS-$(CONFIG_PHASE_FILTER)                  += vf_phase.o
 OBJS-$(CONFIG_PIXDESCTEST_FILTER)            += vf_pixdesctest.o
 OBJS-$(CONFIG_PP_FILTER)                     += vf_pp.o
 OBJS-$(CONFIG_PP7_FILTER)                    += vf_pp7.o
+OBJS-$(CONFIG_PREWITT_FILTER)                += vf_convolution.o
 OBJS-$(CONFIG_PSNR_FILTER)                   += vf_psnr.o dualinput.o framesync.o
 OBJS-$(CONFIG_PULLUP_FILTER)                 += vf_pullup.o
 OBJS-$(CONFIG_QP_FILTER)                     += vf_qp.o
@@ -270,6 +271,7 @@ OBJS-$(CONFIG_SHUFFLEFRAMES_FILTER)          += vf_shuffleframes.o
 OBJS-$(CONFIG_SHUFFLEPLANES_FILTER)          += vf_shuffleplanes.o
 OBJS-$(CONFIG_SIGNALSTATS_FILTER)            += vf_signalstats.o
 OBJS-$(CONFIG_SMARTBLUR_FILTER)              += vf_smartblur.o
+OBJS-$(CONFIG_SOBEL_FILTER)                  += vf_convolution.o
 OBJS-$(CONFIG_SPLIT_FILTER)                  += split.o
 OBJS-$(CONFIG_SPP_FILTER)                    += vf_spp.o
 OBJS-$(CONFIG_SSIM_FILTER)                   += vf_ssim.o dualinput.o framesync.o

libavfilter/allfilters.c

@@ -254,6 +254,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(PIXDESCTEST,    pixdesctest,    vf);
     REGISTER_FILTER(PP,             pp,             vf);
     REGISTER_FILTER(PP7,            pp7,            vf);
+    REGISTER_FILTER(PREWITT,        prewitt,        vf);
     REGISTER_FILTER(PSNR,           psnr,           vf);
     REGISTER_FILTER(PULLUP,         pullup,         vf);
     REGISTER_FILTER(QP,             qp,             vf);
@@ -286,6 +287,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(SHUFFLEPLANES,  shuffleplanes,  vf);
     REGISTER_FILTER(SIGNALSTATS,    signalstats,    vf);
     REGISTER_FILTER(SMARTBLUR,      smartblur,      vf);
+    REGISTER_FILTER(SOBEL,          sobel,          vf);
     REGISTER_FILTER(SPLIT,          split,          vf);
     REGISTER_FILTER(SPP,            spp,            vf);
     REGISTER_FILTER(SSIM,           ssim,           vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  61
+#define LIBAVFILTER_VERSION_MINOR  62
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \