reverted init functions from ffmpeg 3

main.cpp

@@ -82,6 +82,10 @@ int main(int argc, char *argv[]) {
 		qInstallMessageHandler(debug_message_handler);
     }
 
+    // init ffmpeg subsystem
+    av_register_all();
+    avfilter_register_all();
+
     QCoreApplication::setAttribute(Qt::AA_ShareOpenGLContexts);
 
 	QApplication a(argc, argv);