diff --git a/xpra/server/window/window_source.py b/xpra/server/window/window_source.py
index 0d6a879575..07c370f929 100644
--- a/xpra/server/window/window_source.py
+++ b/xpra/server/window/window_source.py
@@ -321,6 +321,12 @@ def add_encoder(self, encoding, encoder):
         self._all_encoders.setdefault(encoding, []).insert(0, encoder)
         self._encoders[encoding] = encoder
 
+    def append_encoder(self, encoding, encoder):
+        log("append_encoder(%s, %s)", encoding, encoder)
+        self._all_encoders.setdefault(encoding, []).append(encoder)
+        if encoding not in self._encoders:
+            self._encoders[encoding] = encoder
+
     def init_encoders(self):
         self._all_encoders = {}
         self._encoders = {}
diff --git a/xpra/server/window/window_video_source.py b/xpra/server/window/window_video_source.py
index e35e17450b..ad5e1767fe 100644
--- a/xpra/server/window/window_video_source.py
+++ b/xpra/server/window/window_video_source.py
@@ -143,7 +143,7 @@ def init_encoders(self):
         self.video_encodings = tuple(x for x in self.video_helper.get_encodings() if x in self.server_core_encodings)
         video_enabled = []
         for x in self.video_encodings:
-            self.add_encoder(x, self.video_encode)
+            self.append_encoder(x, self.video_encode)
             video_enabled.append(x)
         #video_encode() is used for more than just video encoders:
         #(always enable it and let it fall through)