lavfi: add tblend filter

Changelog

@@ -8,6 +8,7 @@ version <next>:
 - RIFX format for *.wav files
 - RTP/mpegts muxer
 - non continuous cache protocol support
+- tblend filter
 
 
 version 2.5:

doc/filters.texi

@@ -2634,13 +2634,17 @@ The threshold below which a pixel value is considered black; it defaults to
 
 @end table
 
-@section blend
+@section blend, tblend
 
 Blend two video frames into each other.
 
-It takes two input streams and outputs one stream, the first input is the
-"top" layer and second input is "bottom" layer.
-Output terminates when shortest input terminates.
+The @code{blend} filter takes two input streams and outputs one
+stream, the first input is the "top" layer and second input is
+"bottom" layer.  Output terminates when shortest input terminates.
+
+The @code{tblend} (time blend) filter takes two consecutive frames
+from one single stream, and outputs the result obtained by blending
+the new frame on top of the old frame.
 
 A description of the accepted options follows.
 
@@ -2730,11 +2734,13 @@ Value of pixel component at current location for second video frame (bottom laye
 @end table
 
 @item shortest
-Force termination when the shortest input terminates. Default is @code{0}.
+Force termination when the shortest input terminates. Default is
+@code{0}. This option is only defined for the @code{blend} filter.
+
 @item repeatlast
 Continue applying the last bottom frame after the end of the stream. A value of
 @code{0} disable the filter after the last frame of the bottom layer is reached.
-Default is @code{1}.
+Default is @code{1}. This option is only defined for the @code{blend} filter.
 @end table
 
 @subsection Examples
@@ -2769,6 +2775,12 @@ Apply uncover up-left effect:
 @example
 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
 @end example
+
+@item
+Display differences between the current and the previous frame:
+@example
+tblend=all_mode=difference128
+@end example
 @end itemize
 
 @section boxblur

libavfilter/Makefile

@@ -188,6 +188,7 @@ OBJS-$(CONFIG_STEREO3D_FILTER)               += vf_stereo3d.o
 OBJS-$(CONFIG_SUBTITLES_FILTER)              += vf_subtitles.o
 OBJS-$(CONFIG_SUPER2XSAI_FILTER)             += vf_super2xsai.o
 OBJS-$(CONFIG_SWAPUV_FILTER)                 += vf_swapuv.o
+OBJS-$(CONFIG_TBLEND_FILTER)                 += vf_blend.o
 OBJS-$(CONFIG_TELECINE_FILTER)               += vf_telecine.o
 OBJS-$(CONFIG_THUMBNAIL_FILTER)              += vf_thumbnail.o
 OBJS-$(CONFIG_TILE_FILTER)                   += vf_tile.o

libavfilter/allfilters.c

@@ -203,6 +203,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(SUBTITLES,      subtitles,      vf);
     REGISTER_FILTER(SUPER2XSAI,     super2xsai,     vf);
     REGISTER_FILTER(SWAPUV,         swapuv,         vf);
+    REGISTER_FILTER(TBLEND,         tblend,         vf);
     REGISTER_FILTER(TELECINE,       telecine,       vf);
     REGISTER_FILTER(THUMBNAIL,      thumbnail,      vf);
     REGISTER_FILTER(TILE,           tile,           vf);

libavfilter/version.h

@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  5
-#define LIBAVFILTER_VERSION_MINOR  5
-#define LIBAVFILTER_VERSION_MICRO 102
+#define LIBAVFILTER_VERSION_MINOR  6
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \