diff --git a/backend/stream_providers.py b/backend/stream_providers.py
index 7a74cf8..fb7e689 100755
--- a/backend/stream_providers.py
+++ b/backend/stream_providers.py
@@ -235,7 +235,9 @@ class SeafileRunner(StreamProvider):
             self.logger.info("%s <%s>", e, self.upstream)
         else:
             stream_data["title"] = json_data.get("filePath")
-            stream_data["upstream"] = json_data.get("rawPath") 
+            stream_data["upstream"] = json_data.get("rawPath")
+            if json_data.get("filePath").lower().endswith(".mp4"):
+                stream_data["ctype"] = "video/mp4"
         return StreamData(**stream_data)
 
 class MetaProvider(StreamProvider):