lavfi: add inverse telecine filter

Approved-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Changelog

@@ -9,6 +9,7 @@ version <next>:
 - libdcadec wrapper
 - Drop support for nvenc API before 5.0
 - nvenc H265 encoder
+- Detelecine filter
 
 
 version 2.6:

doc/filters.texi

@@ -3728,6 +3728,33 @@ FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
 
 @end table
 
+@section detelecine
+
+Apply an exact inverse of the telecine operation. It requires a predefined
+pattern specified using the pattern option which must be the same as that passed
+to the telecine filter.
+
+This filter accepts the following options:
+
+@table @option
+@item first_field
+@table @samp
+@item top, t
+top field first
+@item bottom, b
+bottom field first
+The default value is @code{top}.
+@end table
+
+@item pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is @code{23}.
+
+@item start_frame
+A number representing position of the first frame with respect to the telecine
+pattern. This is to be used if the stream is cut. The default value is @code{0}.
+@end table
+
 @section drawbox
 
 Draw a colored box on the input image.

libavfilter/Makefile

@@ -112,6 +112,7 @@ OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o
 OBJS-$(CONFIG_DEJUDDER_FILTER)               += vf_dejudder.o
 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
+OBJS-$(CONFIG_DETELECINE_FILTER)             += vf_detelecine.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
 OBJS-$(CONFIG_DRAWGRID_FILTER)               += vf_drawbox.o
 OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o

libavfilter/allfilters.c

@@ -128,6 +128,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(DEJUDDER,       dejudder,       vf);
     REGISTER_FILTER(DELOGO,         delogo,         vf);
     REGISTER_FILTER(DESHAKE,        deshake,        vf);
+    REGISTER_FILTER(DETELECINE,     detelecine,     vf);
     REGISTER_FILTER(DRAWBOX,        drawbox,        vf);
     REGISTER_FILTER(DRAWGRID,       drawgrid,       vf);
     REGISTER_FILTER(DRAWTEXT,       drawtext,       vf);