avfilter: add hysteresis filter

Changelog

@@ -19,6 +19,7 @@ version <next>:
 - floating point support in als decoder
 - fifo muxer
 - maskedclamp filter
+- hysteresis filter
 
 
 version 3.1:

doc/filters.texi

@@ -8766,6 +8766,25 @@ If the specified expression is not valid, it is kept at its current
 value.
 @end table
 
+@section hysteresis
+
+Grow first stream into second stream by connecting components.
+This allows to build more robust edge masks.
+
+This filter accepts the following options:
+
+@table @option
+@item planes
+Set which planes will be processed as bitmap, unprocessed planes will be
+copied from first stream.
+By default value 0xf, all planes will be processed.
+
+@item threshold
+Set threshold which is used in filtering. If pixel component value is higher than
+this value filter algorithm for connecting components is activated.
+By default value is 0.
+@end table
+
 @section idet
 
 Detect video interlacing type.

libavfilter/Makefile

@@ -195,6 +195,7 @@ OBJS-$(CONFIG_HUE_FILTER)                    += vf_hue.o
 OBJS-$(CONFIG_HWDOWNLOAD_FILTER)             += vf_hwdownload.o
 OBJS-$(CONFIG_HWUPLOAD_CUDA_FILTER)          += vf_hwupload_cuda.o
 OBJS-$(CONFIG_HWUPLOAD_FILTER)               += vf_hwupload.o
+OBJS-$(CONFIG_HYSTERESIS_FILTER)             += vf_hysteresis.o framesync.o
 OBJS-$(CONFIG_IDET_FILTER)                   += vf_idet.o
 OBJS-$(CONFIG_IL_FILTER)                     += vf_il.o
 OBJS-$(CONFIG_INFLATE_FILTER)                += vf_neighbor.o

libavfilter/allfilters.c

@@ -212,6 +212,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(HWDOWNLOAD,     hwdownload,     vf);
     REGISTER_FILTER(HWUPLOAD,       hwupload,       vf);
     REGISTER_FILTER(HWUPLOAD_CUDA,  hwupload_cuda,  vf);
+    REGISTER_FILTER(HYSTERESIS,     hysteresis,     vf);
     REGISTER_FILTER(IDET,           idet,           vf);
     REGISTER_FILTER(IL,             il,             vf);
     REGISTER_FILTER(INFLATE,        inflate,        vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  53
+#define LIBAVFILTER_VERSION_MINOR  54
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \