lavfi: port phase filter from libmpcodecs

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

Changelog

@@ -16,6 +16,7 @@ version <next>
 - incomplete Voxware MetaSound decoder
 - read EXIF metadata from JPEG
 - DVB teletext decoder
+- phase filter ported from libmpcodecs
 
 
 version 2.0:

LICENSE

@@ -40,6 +40,7 @@ Specifically, the GPL parts of FFmpeg are
     - vf_noise.c
     - vf_owdenoise.c
     - vf_perspective.c
+    - vf_phase.c
     - vf_pp.c
     - vf_sab.c
     - vf_smartblur.c

configure

@@ -2220,6 +2220,7 @@ resample_filter_deps="avresample"
 ocv_filter_deps="libopencv"
 owdenoise_filter_deps="gpl"
 pan_filter_deps="swresample"
+phase_filter_deps="gpl"
 pp_filter_deps="gpl postproc"
 removelogo_filter_deps="avcodec avformat swscale"
 sab_filter_deps="gpl swscale"

doc/filters.texi

@@ -5854,6 +5854,67 @@ It accepts the following values:
 Default value is @samp{linear}.
 @end table
 
+@section phase
+
+Delay interlaced video by one field time so that the field order changes.
+
+The intended use is to fix PAL movies that have been captured with the
+opposite field order to the film-to-video transfer.
+
+A description of the accepted parameters follows.
+
+@table @option
+@item mode
+Set phase mode.
+
+It accepts the following values:
+@table @samp
+@item t
+Capture field order top-first, transfer bottom-first.
+Filter will delay the bottom field.
+
+@item b
+Capture field order bottom-first, transfer top-first.
+Filter will delay the top field.
+
+@item p
+Capture and transfer with the same field order. This mode only exists
+for the documentation of the other options to refer to, but if you
+actually select it, the filter will faithfully do nothing.
+
+@item a
+Capture field order determined automatically by field flags, transfer
+opposite.
+Filter selects among @samp{t} and @samp{b} modes on a frame by frame
+basis using field flags. If no field information is available,
+then this works just like @samp{u}.
+
+@item u
+Capture unknown or varying, transfer opposite.
+Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
+analyzing the images and selecting the alternative that produces best
+match between the fields.
+
+@item T
+Capture top-first, transfer unknown or varying.
+Filter selects among @samp{t} and @samp{p} using image analysis.
+
+@item B
+Capture bottom-first, transfer unknown or varying.
+Filter selects among @samp{b} and @samp{p} using image analysis.
+
+@item A
+Capture determined by field flags, transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
+image analysis. If no field information is available, then this works just
+like @samp{U}. This is the default mode.
+
+@item U
+Both capture and transfer unknown or varying.
+Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
+@end table
+@end table
+
 @section pixdesctest
 
 Pixel format descriptor test filter, mainly useful for internal

libavfilter/Makefile

@@ -168,6 +168,7 @@ OBJS-$(CONFIG_OWDENOISE_FILTER)              += vf_owdenoise.o
 OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
 OBJS-$(CONFIG_PERMS_FILTER)                  += f_perms.o
 OBJS-$(CONFIG_PERSPECTIVE_FILTER)            += vf_perspective.o
+OBJS-$(CONFIG_PHASE_FILTER)                  += vf_phase.o
 OBJS-$(CONFIG_PIXDESCTEST_FILTER)            += vf_pixdesctest.o
 OBJS-$(CONFIG_PP_FILTER)                     += vf_pp.o
 OBJS-$(CONFIG_PSNR_FILTER)                   += vf_psnr.o dualinput.o

libavfilter/allfilters.c

@@ -163,6 +163,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(PAD,            pad,            vf);
     REGISTER_FILTER(PERMS,          perms,          vf);
     REGISTER_FILTER(PERSPECTIVE,    perspective,    vf);
+    REGISTER_FILTER(PHASE,          phase,          vf);
     REGISTER_FILTER(PIXDESCTEST,    pixdesctest,    vf);
     REGISTER_FILTER(PP,             pp,             vf);
     REGISTER_FILTER(PSNR,           psnr,           vf);

libavfilter/version.h

@@ -30,8 +30,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  82
-#define LIBAVFILTER_VERSION_MICRO 102
+#define LIBAVFILTER_VERSION_MINOR  83
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \