avfilter: add lut2 filter

Changelog

@@ -20,6 +20,7 @@ version <next>:
 - fifo muxer
 - maskedclamp filter
 - hysteresis filter
+- lut2 filter
 
 
 version 3.1:

doc/filters.texi

@@ -9253,6 +9253,44 @@ lutyuv=u='(val-maxval/2)*2+maxval/2':v='(val-maxval/2)*2+maxval/2'
 @end example
 @end itemize
 
+@section lut2
+
+Compute and apply a lookup table from two video inputs.
+
+This filter accepts the following parameters:
+@table @option
+@item c0
+set first pixel component expression
+@item c1
+set second pixel component expression
+@item c2
+set third pixel component expression
+@item c3
+set fourth pixel component expression, corresponds to the alpha component
+@end table
+
+Each of them specifies the expression to use for computing the lookup table for
+the corresponding pixel component values.
+
+The exact component associated to each of the @var{c*} options depends on the
+format in inputs.
+
+The expressions can contain the following constants:
+
+@table @option
+@item w
+@item h
+The input width and height.
+
+@item x
+The first input value for the pixel component.
+
+@item y
+The second input value for the pixel component.
+@end table
+
+All expressions default to "x".
+
 @section maskedclamp
 
 Clamp the first input stream with the second input and third input stream.

libavfilter/Makefile

@@ -205,6 +205,7 @@ OBJS-$(CONFIG_KERNDEINT_FILTER)              += vf_kerndeint.o
 OBJS-$(CONFIG_LENSCORRECTION_FILTER)         += vf_lenscorrection.o
 OBJS-$(CONFIG_LOOP_FILTER)                   += f_loop.o
 OBJS-$(CONFIG_LUT_FILTER)                    += vf_lut.o
+OBJS-$(CONFIG_LUT2_FILTER)                   += vf_lut2.o framesync.o
 OBJS-$(CONFIG_LUT3D_FILTER)                  += vf_lut3d.o
 OBJS-$(CONFIG_LUTRGB_FILTER)                 += vf_lut.o
 OBJS-$(CONFIG_LUTYUV_FILTER)                 += vf_lut.o

libavfilter/allfilters.c

@@ -222,6 +222,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(LENSCORRECTION, lenscorrection, vf);
     REGISTER_FILTER(LOOP,           loop,           vf);
     REGISTER_FILTER(LUT,            lut,            vf);
+    REGISTER_FILTER(LUT2,           lut2,           vf);
     REGISTER_FILTER(LUT3D,          lut3d,          vf);
     REGISTER_FILTER(LUTRGB,         lutrgb,         vf);
     REGISTER_FILTER(LUTYUV,         lutyuv,         vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  54
+#define LIBAVFILTER_VERSION_MINOR  55
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \