diff --git a/libavutil/timer.h b/libavutil/timer.h
index 663daf81c6..03706b0d10 100644
--- a/libavutil/timer.h
+++ b/libavutil/timer.h
@@ -80,6 +80,7 @@
             return ts.tv_sec * INT64_C(1000000000) + ts.tv_nsec;
         }
 #       define AV_READ_TIME ff_read_time
+#       define FF_TIMER_UNITS "ns"
 #   endif
 #endif