ffmpeg: Allow specifying the program number for created programs

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

doc/ffmpeg.texi

@@ -355,9 +355,9 @@ To set the language of the first audio stream:
 ffmpeg -i INPUT -metadata:s:a:0 language=eng OUTPUT
 @end example
 
-@item -program [title=@var{title}:]st=@var{stream}[:st=@var{stream}...] (@emph{output})
+@item -program [title=@var{title}:][program_num=@var{program_num}:]st=@var{stream}[:st=@var{stream}...] (@emph{output})
 
-Creates a program with the specified @var{title} and adds the specified
+Creates a program with the specified @var{title}, @var{program_num} and adds the specified
 @var{stream}(s) to it.
 
 @item -target @var{type} (@emph{output})

ffmpeg_opt.c

@@ -2418,8 +2418,27 @@ loop_end:
     for (i = 0; i < o->nb_program; i++) {
         const char *p = o->program[i].u.str;
         int progid = i+1;
-        AVProgram *program = av_new_program(oc, progid);
+        AVProgram *program;
 
+        while(*p) {
+            const char *p2 = av_get_token(&p, ":");
+            char *key;
+            if (!p2)
+                break;
+            if(*p) p++;
+
+            key = av_get_token(&p2, "=");
+            if (!key || !*p2)
+                break;
+            p2++;
+
+            if (!strcmp(key, "program_num"))
+                progid = strtol(p2, NULL, 0);
+        }
+
+        program = av_new_program(oc, progid);
+
+        p = o->program[i].u.str;
         while(*p) {
             const char *p2 = av_get_token(&p, ":");
             char *key;
@@ -2440,6 +2459,7 @@ loop_end:
 
             if (!strcmp(key, "title")) {
                 av_dict_set(&program->metadata, "title", p2, 0);
+            } else if (!strcmp(key, "program_num")) {
             } else if (!strcmp(key, "st")) {
                 int st_num = strtol(p2, NULL, 0);
                 av_program_add_stream_index(oc, progid, st_num);