avfilter: add Audio Video Sync Test filter

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

Changelog

@@ -8,6 +8,7 @@ version 5.1:
 - DFPWM audio encoder/decoder and raw muxer/demuxer
 - SITI filter
 - Vizrt Binary Image encoder/decoder
+- avsynctest source filter
 
 
 version 5.0:

doc/filters.texi

@@ -29282,6 +29282,43 @@ Below is a description of the currently available multimedia sources.
 This is the same as @ref{movie} source, except it selects an audio
 stream by default.
 
+@section avsynctest
+Generate an Audio/Video Sync Test.
+
+Generated stream periodically shows flash video frame and emits beep in audio.
+Useful to inspect A/V sync issues.
+
+It accepts the following options:
+
+@table @option
+@item size, s
+Set output video size. Default value is @code{hd720}.
+
+@item framerate, fr
+Set output video frame rate. Default value is @code{30}.
+
+@item samplerate, sr
+Set output audio sample rate. Default value is @code{44100}.
+
+@item amplitude, a
+Set output audio beep amplitude. Default value is @code{0.7}.
+
+@item period, p
+Set output audio beep period in seconds. Default value is @code{3}.
+
+@item delay, dl
+Set output video flash delay in number of frames. Default value is @code{0}.
+
+@item cycle, c
+Enable cycling of video delays, by default is disabled.
+
+@item duration, d
+Set stream output duration. By default duration is unlimited.
+
+@item fg, bg, ag
+Set foreground/background/additional color.
+@end table
+
 @anchor{movie}
 @section movie
 

libavfilter/Makefile

@@ -579,6 +579,7 @@ OBJS-$(CONFIG_SHOWWAVESPIC_FILTER)           += avf_showwaves.o
 OBJS-$(CONFIG_SPECTRUMSYNTH_FILTER)          += vaf_spectrumsynth.o
 
 # multimedia sources
+OBJS-$(CONFIG_AVSYNCTEST_FILTER)             += src_avsynctest.o
 OBJS-$(CONFIG_AMOVIE_FILTER)                 += src_movie.o
 OBJS-$(CONFIG_MOVIE_FILTER)                  += src_movie.o
 

libavfilter/allfilters.c

@@ -550,6 +550,7 @@ extern const AVFilter ff_avf_showwavespic;
 extern const AVFilter ff_vaf_spectrumsynth;
 
 /* multimedia sources */
+extern const AVFilter ff_avsrc_avsynctest;
 extern const AVFilter ff_avsrc_amovie;
 extern const AVFilter ff_avsrc_movie;
 

libavfilter/version.h

@@ -31,7 +31,7 @@
 
 #include "version_major.h"
 
-#define LIBAVFILTER_VERSION_MINOR  30
+#define LIBAVFILTER_VERSION_MINOR  31
 #define LIBAVFILTER_VERSION_MICRO 100