diff --git a/stream/rtp/rtp.go b/stream/rtp/rtp.go
index 34e30fd3..37d6bbc0 100644
--- a/stream/rtp/rtp.go
+++ b/stream/rtp/rtp.go
@@ -34,9 +34,9 @@ package rtp
 
 const (
 	rtpVer         = 2
-	headSize       = 3 * 4
-	defPayloadSize = 7 * 188
-	defPktSize     = headSize + defPayloadSize
+	headSize       = 3 * 4                     // Header suze of an rtp packet.
+	defPayloadSize = sendLen                   // Default payload size for the rtp packet.
+	defPktSize     = headSize + defPayloadSize // Default packet size is header size + payload size.
 )
 
 // Pkt provides fields consistent with RFC3550 definition of an rtp packet