fix 'local variable referenced before assignment'

ffmpeger.py

@@ -33,6 +33,7 @@ class FFmpeg:
             print('Process already exist, exit...')
         else:
             with Popen(process, stdout=PIPE, stderr=STDOUT) as proc:
+                que = None
                 if watchdog:
                     que = Queue()
                     Process(target=cls._watchdog, args=(proc.pid, sec, que,), daemon=True).start()