diff --git a/player/player.py b/player/player.py
index 769d8b2..51077d8 100755
--- a/player/player.py
+++ b/player/player.py
@@ -28,7 +28,8 @@ CONFIG = {
     "sub_border_color": "0.0/0.0/0.0/0.75",
     "sub_margin": 2 * 36 + 6,
     "sub_spacing": 0,
-    "vf": None
+    "vf": None,
+    "sync_group": None,
 }
 
 
@@ -277,6 +278,8 @@ class Sync(Thread):
                 "%0.4f %s"
                 % (self.mpv.time_pos, self.mpv.playlist_current_pos)
             ).encode()
+            if CONFIG.get("sync_group"):
+                msg = (b"%s " % CONFIG["sync_group"]) + msg
         except:
             return
         try:
@@ -307,6 +310,11 @@ class Sync(Thread):
         except OSError:
             logger.error("socket closed")
         else:
+            if CONFIG.get("sync_group"):
+                if data[0] != str(CONFIG["sync_group"]):
+                    return self.read_position_main()
+                else:
+                    data = data[1:]
             self._last_ping = data[0]
             if data[0] == "pause":
                 self.is_paused = True
diff --git a/render.py b/render.py
index 38e7a16..4cb2c4a 100644
--- a/render.py
+++ b/render.py
@@ -552,7 +552,7 @@ def render_all(options):
             shutil.move(fragment_prefix / "front-5.1.mp4", fragment_prefix / "front.mp4")
             for fn in (
                 "audio-5.1.mp4",
-                "audio-center.wav", "audio-rear.wav", "audio-center.wav",
+                "audio-center.wav", "audio-rear.wav",
                 "audio-front.wav", "audio-back.wav", "back-audio.mp4",
                 "fl.wav", "fr.wav", "fc.wav", "lfe.wav", "bl.wav", "br.wav",
             ):
diff --git a/render_kdenlive.py b/render_kdenlive.py
index 147fbef..2431500 100644
--- a/render_kdenlive.py
+++ b/render_kdenlive.py
@@ -554,7 +554,6 @@ class KDEnliveProject:
                 ] + value)
             ]
 
-
     def properties(self, *props):
         return [
             self.get_element("property", attrib={"name": name}, text=str(value) if value is not None else value)