ffplay: implement -showmode option

The new option allows to select the starting show mode.

doc/ffplay.texi

@@ -58,6 +58,24 @@ Force format.
 Set window title (default is the input filename).
 @item -loop @var{number}
 Loops movie playback <number> times. 0 means forever.
+@item -showmode @var{mode}
+Set the show mode to use.
+Available values for @var{mode} are:
+@table @samp
+@item 0, video
+show video
+@item 1, waves
+show audio waves
+@item 2, rdft
+show audio frequency band using RDFT ((Inverse) Real Discrete Fourier Transform)
+@end table
+
+Default value is "video", if video is not present or cannot be played
+"rdft" is automatically selected.
+
+You can interactively cycle through the available show modes by
+pressing the key @key{w}.
+
 @item -vf @var{filter_graph}
 @var{filter_graph} is a description of the filter graph to apply to
 the input video.

ffplay.c

@@ -265,6 +265,7 @@ static int exit_on_keydown;
 static int exit_on_mousedown;
 static int loop=1;
 static int framedrop=1;
+static int show_mode = SHOW_MODE_VIDEO;
 
 static int rdftspeed=20;
 #if CONFIG_AVFILTER
@@ -2461,6 +2462,8 @@ static int decode_thread(void *arg)
         av_dump_format(ic, 0, is->filename, 0);
     }
 
+    is->show_mode = show_mode;
+
     /* open the streams */
     if (st_index[AVMEDIA_TYPE_AUDIO] >= 0) {
         stream_component_open(is, st_index[AVMEDIA_TYPE_AUDIO]);
@@ -2970,6 +2973,15 @@ static int opt_thread_count(const char *opt, const char *arg)
     return 0;
 }
 
+static int opt_show_mode(const char *opt, const char *arg)
+{
+    show_mode = !strcmp(arg, "video") ? SHOW_MODE_VIDEO :
+                !strcmp(arg, "waves") ? SHOW_MODE_WAVES :
+                !strcmp(arg, "rdft" ) ? SHOW_MODE_RDFT  :
+                parse_number_or_die(opt, arg, OPT_INT, 0, SHOW_MODE_NB-1);
+    return 0;
+}
+
 static const OptionDef options[] = {
 #include "cmdutils_common_opts.h"
     { "x", HAS_ARG | OPT_FUNC2, {(void*)opt_width}, "force displayed width", "width" },
@@ -3013,6 +3025,7 @@ static const OptionDef options[] = {
     { "vf", OPT_STRING | HAS_ARG, {(void*)&vfilters}, "video filters", "filter list" },
 #endif
     { "rdftspeed", OPT_INT | HAS_ARG| OPT_AUDIO | OPT_EXPERT, {(void*)&rdftspeed}, "rdft speed", "msecs" },
+    { "showmode", HAS_ARG | OPT_FUNC2, {(void*)opt_show_mode}, "select show mode (0 = video, 1 = waves, 2 = RDFT)", "mode" },
     { "default", OPT_FUNC2 | HAS_ARG | OPT_AUDIO | OPT_VIDEO | OPT_EXPERT, {(void*)opt_default}, "generic catch all option", "" },
     { "i", OPT_DUMMY, {NULL}, "ffmpeg compatibility dummy option", ""},
     { NULL, },