diff --git a/src/common_video/interface/i420_video_frame.h b/src/common_video/interface/i420_video_frame.h
index e7fc61958..4dd3fb9e7 100644
--- a/src/common_video/interface/i420_video_frame.h
+++ b/src/common_video/interface/i420_video_frame.h
@@ -23,7 +23,8 @@ namespace webrtc {
 enum PlaneType {
   kYPlane = 0,
   kUPlane = 1,
-  kVPlane = 2
+  kVPlane = 2,
+  KNumOfPlanes = 3
 };
 
 class I420VideoFrame {