diff --git a/common_video/include/video_frame.h b/common_video/include/video_frame.h
index 41c3919..2053ea4 100644
--- a/common_video/include/video_frame.h
+++ b/common_video/include/video_frame.h
@@ -16,6 +16,7 @@
 // to refactor and clean up related interfaces, at which point it
 // should be moved to somewhere under api/.
 
+#include "absl/types/optional.h"
 #include "api/video/video_content_type.h"
 #include "api/video/video_rotation.h"
 #include "api/video/video_timing.h"
@@ -39,6 +40,17 @@
 
   void SetEncodeTime(int64_t encode_start_ms, int64_t encode_finish_ms);
 
+  absl::optional<int> SpatialIndex() const {
+    if (spatial_index_ < 0)
+      return absl::nullopt;
+    return spatial_index_;
+  }
+  void SetSpatialIndex(absl::optional<int> spatial_index) {
+    RTC_DCHECK_GE(spatial_index.value_or(0), 0);
+    RTC_DCHECK_LT(spatial_index.value_or(0), kMaxSpatialLayers);
+    spatial_index_ = spatial_index.value_or(-1);
+  }
+
   uint32_t _encodedWidth = 0;
   uint32_t _encodedHeight = 0;
   uint32_t _timeStamp = 0;
@@ -70,6 +82,11 @@
     int64_t receive_start_ms = 0;
     int64_t receive_finish_ms = 0;
   } timing_;
+
+ private:
+  // -1 means not set. Use a plain int rather than optional, to keep this class
+  // copyable with memcpy.
+  int spatial_index_ = -1;
 };
 
 }  // namespace webrtc