avfilter: add video oscilloscope filter

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

Changelog

@@ -5,6 +5,8 @@ version <next>:
 - deflicker video filter
 - doubleweave video filter
 - lumakey video filter
+- pixscope video filter
+- oscilloscope video filter
 
 version 3.3:
 - CrystalHD decoder moved to new decode API

doc/filters.texi

@@ -10233,6 +10233,84 @@ other parameters is 0.
 These parameters correspond to the parameters assigned to the
 libopencv function @code{cvSmooth}.
 
+@section oscilloscope
+
+2D Video Oscilloscope.
+
+Useful to measure spatial impulse, step responses, chroma delays, etc.
+
+It accepts the following parameters:
+
+@table @option
+@item x
+Set scope center x position.
+
+@item y
+Set scope center y position.
+
+@item s
+Set scope size, relative to frame diagonal.
+
+@item t
+Set scope tilt/rotation.
+
+@item o
+Set trace opacity.
+
+@item tx
+Set trace center x position.
+
+@item ty
+Set trace center y position.
+
+@item tw
+Set trace width, relative to width of frame.
+
+@item th
+Set trace height, relative to height of frame.
+
+@item c
+Set which components to trace. By default it traces first three components.
+
+@item g
+Draw trace grid. By default is enabled.
+
+@item st
+Draw some statistics. By default is enabled.
+
+@item sc
+Draw scope. By default is enabled.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Inspect full first row of video frame.
+@example
+oscilloscope=x=0.5:y=0:s=1
+@end example
+
+@item
+Inspect full last row of video frame.
+@example
+oscilloscope=x=0.5:y=1:s=1
+@end example
+
+@item
+Inspect full 5th line of video frame of height 1080.
+@example
+oscilloscope=x=0.5:y=5/1080:s=1
+@end example
+
+@item
+Inspect full last column of video frame.
+@example
+oscilloscope=x=1:y=0.5:s=1:t=1
+@end example
+
+@end itemize
+
 @anchor{overlay}
 @section overlay
 

libavfilter/Makefile

@@ -236,6 +236,7 @@ OBJS-$(CONFIG_NULL_FILTER)                   += vf_null.o
 OBJS-$(CONFIG_OCR_FILTER)                    += vf_ocr.o
 OBJS-$(CONFIG_OCV_FILTER)                    += vf_libopencv.o
 OBJS-$(CONFIG_OPENCL)                        += deshake_opencl.o unsharp_opencl.o
+OBJS-$(CONFIG_OSCILLOSCOPE_FILTER)           += vf_datascope.o
 OBJS-$(CONFIG_OVERLAY_FILTER)                += vf_overlay.o dualinput.o framesync.o
 OBJS-$(CONFIG_OWDENOISE_FILTER)              += vf_owdenoise.o
 OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o

libavfilter/allfilters.c

@@ -246,6 +246,7 @@ static void register_all(void)
     REGISTER_FILTER(NULL,           null,           vf);
     REGISTER_FILTER(OCR,            ocr,            vf);
     REGISTER_FILTER(OCV,            ocv,            vf);
+    REGISTER_FILTER(OSCILLOSCOPE,   oscilloscope,   vf);
     REGISTER_FILTER(OVERLAY,        overlay,        vf);
     REGISTER_FILTER(OWDENOISE,      owdenoise,      vf);
     REGISTER_FILTER(PAD,            pad,            vf);