Initialize ffmpeg in main()

ffmpeg needs to be initialized before scanning songs at startup. As a
consequence, the ffmpeg plugin does not need to call av_register_all()
itself anymore.

src/main.c

@@ -94,6 +94,7 @@
 # include "getopt.h"
 #endif
 
+#include <libavformat/avformat.h>
 
 /** Seconds to sleep before checking for a shutdown or reload */
 #define MAIN_SLEEP_INTERVAL  2
@@ -431,6 +432,8 @@ int main(int argc, char *argv[]) {
     DPRINTF(E_LOG,L_MAIN,"Firefly Version %s: Starting with debuglevel %d\n",
             VERSION,err_getlevel());
 
+    /* initialize ffmpeg */
+    av_register_all();
 
     /* load plugins before we drop privs?  Maybe... let the
      * plugins do stuff they might need to */

src/plugins/ssc-ffmpeg.c

@@ -131,7 +131,8 @@ char *ssc_ffmpeg_error(void *pv) {
 }
 
 PLUGIN_INFO *plugin_info(void) {
-    av_register_all();
+    /* Now done in main() */
+    /* av_register_all(); */
 
     return &_pi;
 }