fftools/ffmpeg: set want_sdp when initializing the muxer

Allows making the variable local to ffmpeg_mux.

fftools/ffmpeg.c

@@ -137,8 +137,6 @@ static int64_t nb_frames_drop = 0;
 static int64_t decode_error_stat[2];
 unsigned nb_output_dumped = 0;
 
-int want_sdp = 1;
-
 static BenchmarkTimeStamps current_time;
 AVIOContext *progress_avio = NULL;
 
@@ -4513,7 +4511,7 @@ static int64_t getmaxrss(void)
 
 int main(int argc, char **argv)
 {
-    int i, ret;
+    int ret;
     BenchmarkTimeStamps ti;
 
     init_dynload();
@@ -4549,11 +4547,6 @@ int main(int argc, char **argv)
         exit_program(1);
     }
 
-    for (i = 0; i < nb_output_files; i++) {
-        if (strcmp(output_files[i]->format->name, "rtp"))
-            want_sdp = 0;
-    }
-
     current_time = ti = get_benchmark_time_stamps();
     if (transcode() < 0)
         exit_program(1);

fftools/ffmpeg.h

@@ -656,7 +656,6 @@ extern char *qsv_device;
 #endif
 extern HWDevice *filter_hw_device;
 
-extern int want_sdp;
 extern unsigned nb_output_dumped;
 extern int main_return_code;
 

fftools/ffmpeg_mux.c

@@ -38,6 +38,8 @@ struct Muxer {
     int header_written;
 };
 
+static int want_sdp = 1;
+
 static void close_all_output_streams(OutputStream *ost, OSTFinished this_stream, OSTFinished others)
 {
     int i;
@@ -335,6 +337,9 @@ int of_muxer_init(OutputFile *of, int64_t limit_filesize)
 
     mux->limit_filesize = limit_filesize;
 
+    if (strcmp(of->format->name, "rtp"))
+        want_sdp = 0;
+
     return 0;
 }