diff --git a/common/webmdec.h b/common/webmdec.h
index 5ac75cb..fcbdeff 100644
--- a/common/webmdec.h
+++ b/common/webmdec.h
@@ -28,7 +28,7 @@
   const void *block;
   int block_frame_index;
   int video_track_index;
-  uint64_t timestamp_ns;
+  int64_t timestamp_ns;
   int is_key_frame;
   int reached_eos;
 };