avfilter: add waveform monitor filter

Changelog

@@ -33,6 +33,7 @@ version <next>:
 - aphasemeter filter
 - showfreqs filter
 - vectorscope filter
+- waveform filter
 
 
 version 2.7:

doc/filters.texi

@@ -10927,6 +10927,82 @@ Only deinterlace frames marked as interlaced.
 Default value is @samp{all}.
 @end table
 
+@section waveform
+Video waveform monitor.
+
+The waveform monitor plots color component intensity. By default luminance
+only. Each column of the waveform corresponds to a column of pixels in the
+source video.
+
+It accepts the following options:
+
+@table @option
+@item mode, m
+Can be either @code{row}, or @code{column}. Default is @code{column}.
+In row mode, the graph on the left side represents color component value 0 and
+the right side represents value = 255. In column mode, the top side represents
+color component value = 0 and bottom side represents value = 255.
+
+@item intensity, i
+Set intensity. Smaller values are useful to find out how many values of the same
+luminance are distributed across input rows/columns.
+Default value is @code{10}. Allowed range is [1, 255].
+
+@item mirror, r
+Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
+In mirrored mode, higher values will be represented on the left
+side for @code{row} mode and at the top for @code{column} mode. Default is
+@code{1} (mirrored).
+
+@item display, d
+Set display mode.
+It accepts the following values:
+@table @samp
+@item overlay
+Presents information identical to that in the @code{parade}, except
+that the graphs representing color components are superimposed directly
+over one another.
+
+This display mode makes it easier to spot relative differences or similarities
+in overlapping areas of the color components that are supposed to be identical,
+such as neutral whites, grays, or blacks.
+
+@item parade
+Display separate graph for the color components side by side in
+@code{row} mode or one below the other in @code{column} mode.
+
+Using this display mode makes it easy to spot color casts in the highlights
+and shadows of an image, by comparing the contours of the top and the bottom
+graphs of each waveform. Since whites, grays, and blacks are characterized
+by exactly equal amounts of red, green, and blue, neutral areas of the picture
+should display three waveforms of roughly equal width/height. If not, the
+correction is easy to perform by making level adjustments the three waveforms.
+@end table
+Default is @code{parade}.
+
+@item components, c
+Set which color components to display. Default is 1, which means only luminance
+or red color component if input is in RGB colorspace. If is set for example to
+7 it will display all 3 (if) available color components.
+
+@item envelope, e
+@table @samp
+@item none
+No envelope, this is default.
+
+@item instant
+Instant envelope, minimum and maximum values presented in graph will be easily
+visible even with small @code{step} value.
+
+@item peak
+Hold minimum and maximum values presented in graph across time. This way you
+can still spot out of range values without constantly looking at waveforms.
+
+@item peak+instant
+Peak and instant envelope combined together.
+@end table
+@end table
+
 @section xbr
 Apply the xBR high-quality magnification filter which is designed for pixel
 art. It follows a set of edge-detection rules, see

libavfilter/Makefile

@@ -232,6 +232,7 @@ OBJS-$(CONFIG_VIDSTABDETECT_FILTER)          += vidstabutils.o vf_vidstabdetect.
 OBJS-$(CONFIG_VIDSTABTRANSFORM_FILTER)       += vidstabutils.o vf_vidstabtransform.o
 OBJS-$(CONFIG_VIGNETTE_FILTER)               += vf_vignette.o
 OBJS-$(CONFIG_W3FDIF_FILTER)                 += vf_w3fdif.o
+OBJS-$(CONFIG_WAVEFORM_FILTER)               += vf_waveform.o
 OBJS-$(CONFIG_XBR_FILTER)                    += vf_xbr.o
 OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
 OBJS-$(CONFIG_ZMQ_FILTER)                    += f_zmq.o

libavfilter/allfilters.c

@@ -247,6 +247,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(VIDSTABTRANSFORM, vidstabtransform, vf);
     REGISTER_FILTER(VIGNETTE,       vignette,       vf);
     REGISTER_FILTER(W3FDIF,         w3fdif,         vf);
+    REGISTER_FILTER(WAVEFORM,       waveform,       vf);
     REGISTER_FILTER(XBR,            xbr,            vf);
     REGISTER_FILTER(YADIF,          yadif,          vf);
     REGISTER_FILTER(ZMQ,            zmq,            vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  5
-#define LIBAVFILTER_VERSION_MINOR  36
+#define LIBAVFILTER_VERSION_MINOR  37
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_histogram.c

@@ -172,6 +172,7 @@ static int config_output(AVFilterLink *outlink)
         outlink->h = (h->level_height + h->scale_height) * FFMAX(ncomp * h->display_mode, 1);
         break;
     case MODE_WAVEFORM:
+        av_log(ctx, AV_LOG_WARNING, "This mode is deprecated, please use waveform filter instead.\n");
         if (h->waveform_mode)
             outlink->h = 256 * FFMAX(h->ncomp * h->display_mode, 1);
         else