diff --git a/trunk/src/kernel/srs_kernel_rtp.cpp b/trunk/src/kernel/srs_kernel_rtp.cpp
index 9f8a3b671..d00140005 100644
--- a/trunk/src/kernel/srs_kernel_rtp.cpp
+++ b/trunk/src/kernel/srs_kernel_rtp.cpp
@@ -157,6 +157,7 @@ void SrsRtpHeader::set_ssrc(uint32_t ssrc)
 SrsRtpPacket2::SrsRtpPacket2()
 {
     payload = NULL;
+    padding = 0;
 }
 
 SrsRtpPacket2::~SrsRtpPacket2()
@@ -164,6 +165,17 @@ SrsRtpPacket2::~SrsRtpPacket2()
     srs_freep(payload);
 }
 
+void SrsRtpPacket2::set_padding(int size)
+{
+    rtp_header.set_padding(size > 0);
+    padding = size;
+}
+
+int SrsRtpPacket2::nb_bytes()
+{
+    return rtp_header.header_size() + (payload? payload->nb_bytes():0) + padding;
+}
+
 srs_error_t SrsRtpPacket2::encode(SrsBuffer* buf)
 {
     srs_error_t err = srs_success;
@@ -176,6 +188,14 @@ srs_error_t SrsRtpPacket2::encode(SrsBuffer* buf)
         return srs_error_wrap(err, "encode payload");
     }
 
+    if (padding) {
+        if (!buf->require(padding)) {
+            return srs_error_new(ERROR_RTC_RTP_MUXER, "requires %d bytes", padding);
+        }
+        memset(buf->data(), padding, padding);
+        buf->skip(padding);
+    }
+
     return err;
 }
 
diff --git a/trunk/src/kernel/srs_kernel_rtp.hpp b/trunk/src/kernel/srs_kernel_rtp.hpp
index 6fe5f32ef..975b2b463 100644
--- a/trunk/src/kernel/srs_kernel_rtp.hpp
+++ b/trunk/src/kernel/srs_kernel_rtp.hpp
@@ -74,6 +74,7 @@ public:
     int64_t get_timestamp() const { return timestamp; }
     void set_ssrc(uint32_t ssrc);
     uint32_t get_ssrc() const { return ssrc; }
+    void set_padding(bool v) { padding = v; }
 };
 
 class SrsRtpPacket2
@@ -81,10 +82,16 @@ class SrsRtpPacket2
 public:
     SrsRtpHeader rtp_header;
     ISrsEncoder* payload;
+    int padding;
 public:
     SrsRtpPacket2();
     virtual ~SrsRtpPacket2();
 public:
+    // Append size of bytes as padding.
+    virtual void set_padding(int size);
+// interface ISrsEncoder
+public:
+    virtual int nb_bytes();
     virtual srs_error_t encode(SrsBuffer* buf);
 };