lavfi: add showspectrum filter.

Changelog

@@ -23,7 +23,7 @@ version next:
 - RTMPTS protocol support
 - RTMPE protocol support
 - RTMPTE protocol support
-- showwaves filter
+- showwaves and showspectrum filter
 - LucasArts SMUSH playback support
 - SAMI, RealText and SubViewer demuxers and decoders
 - Heart Of Darkness PAF playback support

configure

@@ -1849,6 +1849,7 @@ pan_filter_deps="swresample"
 removelogo_filter_deps="avcodec avformat swscale"
 scale_filter_deps="swscale"
 select_filter_deps="avcodec"
+showspectrum_filter_deps="avcodec"
 super2xsai_filter_deps="gpl"
 tinterlace_filter_deps="gpl"
 yadif_filter_deps="gpl"

doc/filters.texi

@@ -4252,6 +4252,20 @@ do not have exactly the same duration in the first file.
 
 @end itemize
 
+@section showspectrum
+
+Convert input audio to a video output, representing the audio frequency
+spectrum.
+
+The filter accepts the following named parameters:
+@table @option
+@item size, s
+Specify the video size for the output. Default value is @code{640x480}.
+@end table
+
+The usage is very similar to the showwaves filter; see the examples in that
+section.
+
 @section showwaves
 
 Convert input audio to a video output, representing the samples waves.

libavfilter/Makefile

@@ -202,6 +202,7 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/pullup.o
 
 # multimedia filters
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o
+OBJS-$(CONFIG_SHOWSPECTRUM_FILTER)           += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWWAVES_FILTER)              += avf_showwaves.o
 
 # multimedia sources

libavfilter/allfilters.c

@@ -143,6 +143,7 @@ void avfilter_register_all(void)
 
     /* multimedia filters */
     REGISTER_FILTER (CONCAT,      concat,      avf);
+    REGISTER_FILTER (SHOWSPECTRUM,showspectrum,avf);
     REGISTER_FILTER (SHOWWAVES,   showwaves,   avf);
 
     /* multimedia sources */

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  3
-#define LIBAVFILTER_VERSION_MINOR  11
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR  12
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \