diff --git a/trunk/src/app/srs_app_rtc_conn.cpp b/trunk/src/app/srs_app_rtc_conn.cpp
index 73bc97ff2..81ea393f8 100644
--- a/trunk/src/app/srs_app_rtc_conn.cpp
+++ b/trunk/src/app/srs_app_rtc_conn.cpp
@@ -400,6 +400,11 @@ SrsRtcPlayStream::SrsRtcPlayStream(SrsRtcConnection* s, const SrsContextId& cid)
 
 SrsRtcPlayStream::~SrsRtcPlayStream()
 {
+    // TODO: FIXME: Should not do callback in de-constructor?
+    if (_srs_rtc_hijacker) {
+        _srs_rtc_hijacker->on_stop_play(session_, this, req_);
+    }
+
     _srs_config->unsubscribe(this);
 
     srs_freep(nack_epp);
@@ -933,16 +938,20 @@ SrsRtcPublishStream::SrsRtcPublishStream(SrsRtcConnection* session, const SrsCon
 
 SrsRtcPublishStream::~SrsRtcPublishStream()
 {
-    if (_srs_rtc_hijacker) {
-        _srs_rtc_hijacker->on_stop_publish(session_, this, req);
-    }
-
     // TODO: FIXME: Should remove and delete source.
     if (source) {
         source->set_publish_stream(NULL);
         source->on_unpublish();
     }
 
+    // TODO: FIXME: Should not do callback in de-constructor?
+    // NOTE: on_stop_publish lead to switch io,
+    // it must be called after source stream unpublish (set source stream is_created=false).
+    // if not, it lead to republish failed.
+    if (_srs_rtc_hijacker) {
+        _srs_rtc_hijacker->on_stop_publish(session_, this, req);
+    }
+
     for (int i = 0; i < (int)video_tracks_.size(); ++i) {
         SrsRtcVideoRecvTrack* track = video_tracks_.at(i);
         srs_freep(track);
@@ -1779,6 +1788,7 @@ srs_error_t SrsRtcConnection::add_publisher(SrsRequest* req, const SrsSdp& remot
     SrsRtcStreamDescription* stream_desc = new SrsRtcStreamDescription();
     SrsAutoFree(SrsRtcStreamDescription, stream_desc);
 
+    // TODO: FIXME: Change to api of stream desc.
     if ((err = negotiate_publish_capability(req, remote_sdp, stream_desc)) != srs_success) {
         return srs_error_wrap(err, "publish negotiate");
     }
diff --git a/trunk/src/app/srs_app_rtc_conn.hpp b/trunk/src/app/srs_app_rtc_conn.hpp
index e04c9671e..8b7e2f9cc 100644
--- a/trunk/src/app/srs_app_rtc_conn.hpp
+++ b/trunk/src/app/srs_app_rtc_conn.hpp
@@ -575,6 +575,8 @@ public:
     virtual srs_error_t on_before_play(SrsRtcConnection* session, SrsRequest* req) = 0;
     // When start player by RTC.
     virtual srs_error_t on_start_play(SrsRtcConnection* session, SrsRtcPlayStream* player, SrsRequest* req) = 0;
+    // When stop player by RTC.
+    virtual void on_stop_play(SrsRtcConnection* session, SrsRtcPlayStream* player, SrsRequest* req) = 0;
     // When start consuming for player for RTC.
     virtual srs_error_t on_start_consume(SrsRtcConnection* session, SrsRtcPlayStream* player, SrsRequest* req, SrsRtcConsumer* consumer) = 0;
 };
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
index 9396d867c..f5f6959d3 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
@@ -179,6 +179,58 @@ void SrsRtpExtensionTwcc::set_sn(uint16_t sn)
     has_twcc_ = true;
 }
 
+SrsRtpExtensionOneByte::SrsRtpExtensionOneByte() : has_ext_(false), id_(0), value_(0)
+{
+}
+
+void SrsRtpExtensionOneByte::set_id(int id)
+{
+    id_ = id;
+    has_ext_ = true;
+}
+
+void SrsRtpExtensionOneByte::set_value(uint8_t value)
+{
+    value_ = value;
+    has_ext_ = true;
+}
+
+srs_error_t SrsRtpExtensionOneByte::decode(SrsBuffer* buf)
+{
+    srs_error_t err = srs_success;
+
+    if (!buf->require(2)) {
+        return srs_error_new(ERROR_RTC_RTP_MUXER, "requires %d bytes", 2);
+    }
+    uint8_t v = buf->read_1bytes();
+
+    id_ = (v & 0xF0) >> 4;
+    uint8_t len = (v & 0x0F);
+    if(!id_ || len != 0) {
+        return srs_error_new(ERROR_RTC_RTP, "invalid rtp extension id=%d, len=%d", id_, len);
+    }
+
+    value_ = buf->read_1bytes();
+
+    has_ext_ = true;
+    return err;
+}
+
+srs_error_t SrsRtpExtensionOneByte::encode(SrsBuffer* buf)
+{
+    srs_error_t err = srs_success;
+
+    if (!buf->require(2)) {
+        return srs_error_new(ERROR_RTC_RTP_MUXER, "requires %d bytes", 2);
+    }
+
+    uint8_t id_len = (id_ & 0x0F)<< 4 | 0x00;
+    buf->write_1bytes(id_len);
+    buf->write_1bytes(value_);
+
+    return err;
+}
+
 SrsRtpExtensions::SrsRtpExtensions() : has_ext_(false)
 {
 }
@@ -252,6 +304,11 @@ srs_error_t SrsRtpExtensions::decode_0xbede(SrsBuffer* buf)
                 return srs_error_wrap(err, "decode twcc extension");
             }
             has_ext_ = true;
+        } else if (xtype == kRtpExtensionAudioLevel) {
+            if((err = audio_level_.decode(buf)) != srs_success) {
+                return srs_error_wrap(err, "decode audio level extension");
+            }
+            has_ext_ = true;
         } else {
             buf->skip(1 + (len + 1));
         }
@@ -263,6 +320,7 @@ srs_error_t SrsRtpExtensions::decode_0xbede(SrsBuffer* buf)
 uint64_t SrsRtpExtensions::nb_bytes()
 {
     int size =  4 + (twcc_.has_twcc_ext() ? twcc_.nb_bytes() : 0);
+    size += (audio_level_.exists() ? audio_level_.nb_bytes() : 0);
     // add padding
     size += (size % 4 == 0) ? 0 : (4 - size % 4);
     return size;
@@ -281,6 +339,10 @@ srs_error_t SrsRtpExtensions::encode(SrsBuffer* buf)
         len += twcc_.nb_bytes();
     }
 
+    if (audio_level_.exists()) {
+        len += audio_level_.nb_bytes();
+    }
+
     int padding_count = (len % 4 == 0) ? 0 : (4 - len % 4);
     len += padding_count;
 
@@ -293,6 +355,12 @@ srs_error_t SrsRtpExtensions::encode(SrsBuffer* buf)
         }
     }
 
+    if (audio_level_.exists()) {
+        if (srs_success != (err = audio_level_.encode(buf))) {
+            return srs_error_wrap(err, "encode audio level extension");
+        }
+    }
+
     // add padding
     while(padding_count > 0) {
         buf->write_1bytes(0);
@@ -331,6 +399,23 @@ srs_error_t SrsRtpExtensions::set_twcc_sequence_number(uint8_t id, uint16_t sn)
     return srs_success;
 }
 
+srs_error_t SrsRtpExtensions::get_audio_level(uint8_t& level)
+{
+    if(audio_level_.exists()) {
+        level = audio_level_.get_value();
+        return srs_success;
+    }
+    return srs_error_new(ERROR_RTC_RTP_MUXER, "not find rtp extension audio level");
+}
+
+srs_error_t SrsRtpExtensions::set_audio_level(int id, uint8_t level)
+{
+    has_ext_ = true;
+    audio_level_.set_id(id);
+    audio_level_.set_value(level);
+    return srs_success;
+}
+
 SrsRtpHeader::SrsRtpHeader()
 {
     padding_length   = 0;
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
index 76a39fbc5..e5e647b69 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
@@ -86,9 +86,12 @@ enum SrsRtpExtensionType
 {
     kRtpExtensionNone,
     kRtpExtensionTransportSequenceNumber,
+    kRtpExtensionAudioLevel,
     kRtpExtensionNumberOfExtensions  // Must be the last entity in the enum.
 };
 
+const std::string kAudioLevelUri = "urn:ietf:params:rtp-hdrext:ssrc-audio-level";
+
 struct SrsExtensionInfo
 {
     SrsRtpExtensionType type;
@@ -96,7 +99,8 @@ struct SrsExtensionInfo
 };
 
 const SrsExtensionInfo kExtensions[] = {
-    {kRtpExtensionTransportSequenceNumber, std::string("http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01")}
+    {kRtpExtensionTransportSequenceNumber, std::string("http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01")},
+    {kRtpExtensionAudioLevel, kAudioLevelUri},
 };
 
 class SrsRtpExtensionTypes
@@ -138,12 +142,34 @@ public:
     virtual uint64_t nb_bytes();
 };
 
+class SrsRtpExtensionOneByte : public ISrsCodec
+{
+    bool has_ext_;
+    int id_;
+    uint8_t value_;
+public:
+    SrsRtpExtensionOneByte();
+    virtual ~SrsRtpExtensionOneByte() {}
+
+    bool exists() { return has_ext_; }
+    int get_id() { return id_; }
+    uint8_t get_value() { return value_; }
+    void set_id(int id);
+    void set_value(uint8_t value);
+public:
+    // ISrsCodec
+    virtual srs_error_t decode(SrsBuffer* buf);
+    virtual srs_error_t encode(SrsBuffer* buf);
+    virtual uint64_t nb_bytes() { return 2; };
+};
+
 class SrsRtpExtensions : public ISrsCodec
 {
 private:
     bool has_ext_;
     SrsRtpExtensionTypes types_;
     SrsRtpExtensionTwcc twcc_;
+    SrsRtpExtensionOneByte audio_level_;
 public:
     SrsRtpExtensions();
     virtual ~SrsRtpExtensions();
@@ -152,6 +178,8 @@ public:
     void set_types_(const SrsRtpExtensionTypes* types);
     srs_error_t get_twcc_sequence_number(uint16_t& twcc_sn);
     srs_error_t set_twcc_sequence_number(uint8_t id, uint16_t sn);
+    srs_error_t get_audio_level(uint8_t& level);
+    srs_error_t set_audio_level(int id, uint8_t level);
 
 // ISrsCodec
 public:
@@ -257,7 +285,7 @@ public:
     // Whether the packet is Audio packet.
     bool is_audio();
     // Copy the RTP packet.
-    SrsRtpPacket2* copy();
+    virtual SrsRtpPacket2* copy();
     // Set RTP header extensions for encoding or decoding header extension
     void set_extension_types(const SrsRtpExtensionTypes* v);
 // interface ISrsEncoder