avfilter: add ahistogram multimedia filter

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

Changelog

@@ -53,6 +53,7 @@ version <next>:
 - showspectrumpic filter
 - libstagefright support removed
 - spectrumsynth filter
+- ahistogram filter
 
 
 version 2.8:

doc/filters.texi

@@ -13282,6 +13282,84 @@ tools.
 
 Below is a description of the currently available multimedia filters.
 
+@section ahistogram
+
+Convert input audio to a video output, displaying the volume histogram.
+
+The filter accepts the following options:
+
+@table @option
+@item dmode
+Specify how histogram is calculated.
+
+It accepts the following values:
+@table @samp
+@item single
+Use single histogram for all channels.
+@item separate
+Use separate histogram for each channel.
+@end table
+Default is @code{single}.
+
+@item rate, r
+Set frame rate, expressed as number of frames per second. Default
+value is "25".
+
+@item size, s
+Specify the video size for the output. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default value is @code{hd720}.
+
+@item scale
+Set display scale.
+
+It accepts the following values:
+@table @samp
+@item log
+logarithmic
+@item sqrt
+square root
+@item cbrt
+cubic root
+@item lin
+linear
+@item rlog
+reverse logarithmic
+@end table
+Default is @code{log}.
+
+@item ascale
+Set amplitude scale.
+
+It accepts the following values:
+@table @samp
+@item log
+logarithmic
+@item lin
+linear
+@end table
+Default is @code{log}.
+
+@item acount
+Set how much frames to accumulate in histogram.
+Defauls is 1. Setting this to -1 accumulates all frames.
+
+@item rheight
+Set histogram ratio of window height.
+
+@item slide
+Set sonogram sliding.
+
+It accepts the following values:
+@table @samp
+@item replace
+replace old rows with new ones.
+@item scroll
+scroll from top to bottom.
+@end table
+Default is @code{replace}.
+@end table
+
 @section aphasemeter
 
 Convert input audio to a video output, displaying the audio phase.

libavfilter/Makefile

@@ -280,6 +280,7 @@ OBJS-$(CONFIG_NULLSINK_FILTER)               += vsink_nullsink.o
 
 # multimedia filters
 OBJS-$(CONFIG_ADRAWGRAPH_FILTER)             += f_drawgraph.o
+OBJS-$(CONFIG_AHISTOGRAM_FILTER)             += avf_ahistogram.o
 OBJS-$(CONFIG_APHASEMETER_FILTER)            += avf_aphasemeter.o
 OBJS-$(CONFIG_AVECTORSCOPE_FILTER)           += avf_avectorscope.o
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o

libavfilter/allfilters.c

@@ -300,6 +300,7 @@ void avfilter_register_all(void)
 
     /* multimedia filters */
     REGISTER_FILTER(ADRAWGRAPH,     adrawgraph,     avf);
+    REGISTER_FILTER(AHISTOGRAM,     ahistogram,     avf);
     REGISTER_FILTER(APHASEMETER,    aphasemeter,    avf);
     REGISTER_FILTER(AVECTORSCOPE,   avectorscope,   avf);
     REGISTER_FILTER(CONCAT,         concat,         avf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  24
+#define LIBAVFILTER_VERSION_MINOR  25
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \