diff --git a/src/main/resources/nis.properties b/src/main/resources/nis.properties
index a29c34ed2..dce64af7a 100644
--- a/src/main/resources/nis.properties
+++ b/src/main/resources/nis.properties
@@ -528,4 +528,6 @@ log_time_end=2018-10-01 00:00:00
 area_tag=location
 isp_tag=isp
 mmFileDigestLog=mmFileDigestLogs
-ntcStreamMediaLog=ntcStreamMediaLogs
\ No newline at end of file
+ntcStreamMediaLog=ntcStreamMediaLogs
+#音视频样例限制时长，单位秒
+av_duration_limit=10
\ No newline at end of file