diff --git a/livekit-ffi/protocol/video_frame.proto b/livekit-ffi/protocol/video_frame.proto
index 6ce0a2bc..528b14f4 100644
--- a/livekit-ffi/protocol/video_frame.proto
+++ b/livekit-ffi/protocol/video_frame.proto
@@ -98,6 +98,8 @@ enum VideoRotation {
   VIDEO_ROTATION_270 = 3;
 }
 
+// Values of this enum must not be changed
+// It is used to serialize a rtc.VideoFrame on Python
 enum VideoBufferType {
   RGBA = 0;
   ABGR = 1;