diff --git a/webrtc/video_engine/include/vie_rtp_rtcp.h b/webrtc/video_engine/include/vie_rtp_rtcp.h
index d36b341ba..e2f079544 100644
--- a/webrtc/video_engine/include/vie_rtp_rtcp.h
+++ b/webrtc/video_engine/include/vie_rtp_rtcp.h
@@ -242,6 +242,16 @@ class WEBRTC_DLLEXPORT ViERTP_RTCP {
                                               bool enable,
                                               int id) = 0;
 
+  // Enables RTP absolute send time header extension. This call must be done
+  // before ViECodec::SetSendCodec is called.
+  virtual int SetSendAbsoluteSendTimeStatus(int video_channel,
+                                            bool enable,
+                                            int id) = 0;
+
+  virtual int SetReceiveAbsoluteSendTimeStatus(int video_channel,
+                                               bool enable,
+                                               int id) = 0;
+
   // Enables transmission smoothening, i.e. packets belonging to the same frame
   // will be sent over a longer period of time instead of sending them
   // back-to-back.
diff --git a/webrtc/video_engine/test/auto_test/source/vie_autotest_rtp_rtcp.cc b/webrtc/video_engine/test/auto_test/source/vie_autotest_rtp_rtcp.cc
index d94681a52..03d5b5eb9 100644
--- a/webrtc/video_engine/test/auto_test/source/vie_autotest_rtp_rtcp.cc
+++ b/webrtc/video_engine/test/auto_test/source/vie_autotest_rtp_rtcp.cc
@@ -718,7 +718,7 @@ void ViEAutoTest::ViERtpRtcpAPITest()
       EXPECT_EQ(0, ViE.rtp_rtcp->SetNACKStatus(tbChannel.videoChannel, true));
     }
 
-    // Timsetamp offset extension.
+    // Timestamp offset extension.
     // Valid range is 1 to 14 inclusive.
     EXPECT_EQ(-1, ViE.rtp_rtcp->SetSendTimestampOffsetStatus(
         tbChannel.videoChannel, true, 0));
@@ -754,6 +754,42 @@ void ViEAutoTest::ViERtpRtcpAPITest()
     EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveTimestampOffsetStatus(
             tbChannel.videoChannel, false, 3));
 
+    // Absolute send time extension.
+    // Valid range is 1 to 14 inclusive.
+    EXPECT_EQ(-1, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 0));
+    EXPECT_EQ(-1, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 15));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetSendAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+
+    EXPECT_EQ(-1, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 0));
+    EXPECT_EQ(-1, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 15));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, true, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+    EXPECT_EQ(0, ViE.rtp_rtcp->SetReceiveAbsoluteSendTimeStatus(
+        tbChannel.videoChannel, false, 3));
+
     // Transmission smoothening.
     const int invalid_channel_id = 17;
     EXPECT_EQ(-1, ViE.rtp_rtcp->SetTransmissionSmoothingStatus(
diff --git a/webrtc/video_engine/vie_channel.cc b/webrtc/video_engine/vie_channel.cc
index 53124a656..2129742af 100644
--- a/webrtc/video_engine/vie_channel.cc
+++ b/webrtc/video_engine/vie_channel.cc
@@ -90,6 +90,7 @@ ViEChannel::ViEChannel(int32_t channel_id,
       bandwidth_observer_(bandwidth_observer),
       rtp_packet_timeout_(false),
       send_timestamp_extension_id_(kInvalidRtpExtensionId),
+      absolute_send_time_extension_id_(kInvalidRtpExtensionId),
       using_packet_spread_(false),
       external_transport_(NULL),
       decoder_reset_(true),
@@ -370,6 +371,21 @@ int32_t ViEChannel::SetSendCodec(const VideoCodec& video_codec,
         rtp_rtcp->DeregisterSendRtpHeaderExtension(
             kRtpExtensionTransmissionTimeOffset);
       }
+      if (absolute_send_time_extension_id_ != kInvalidRtpExtensionId) {
+        // Deregister in case the extension was previously enabled.
+        rtp_rtcp->DeregisterSendRtpHeaderExtension(
+            kRtpExtensionAbsoluteSendTime);
+        if (rtp_rtcp->RegisterSendRtpHeaderExtension(
+            kRtpExtensionAbsoluteSendTime,
+            absolute_send_time_extension_id_) != 0) {
+          WEBRTC_TRACE(kTraceError, kTraceVideo, ViEId(engine_id_, channel_id_),
+                       "%s: could not register absolute send time extension",
+                       __FUNCTION__);
+        }
+      } else {
+        rtp_rtcp->DeregisterSendRtpHeaderExtension(
+            kRtpExtensionAbsoluteSendTime);
+      }
     }
     // |RegisterSimulcastRtpRtcpModules| resets all old weak pointers and old
     // modules can be deleted after this step.
@@ -865,6 +881,47 @@ int ViEChannel::SetReceiveTimestampOffsetStatus(bool enable, int id) {
   }
 }
 
+int ViEChannel::SetSendAbsoluteSendTimeStatus(bool enable, int id) {
+  CriticalSectionScoped cs(rtp_rtcp_cs_.get());
+  int error = 0;
+  if (enable) {
+    // Enable the extension, but disable possible old id to avoid errors.
+    absolute_send_time_extension_id_ = id;
+    rtp_rtcp_->DeregisterSendRtpHeaderExtension(
+        kRtpExtensionAbsoluteSendTime);
+    error = rtp_rtcp_->RegisterSendRtpHeaderExtension(
+        kRtpExtensionAbsoluteSendTime, id);
+    for (std::list<RtpRtcp*>::iterator it = simulcast_rtp_rtcp_.begin();
+         it != simulcast_rtp_rtcp_.end(); it++) {
+      (*it)->DeregisterSendRtpHeaderExtension(
+          kRtpExtensionAbsoluteSendTime);
+      error |= (*it)->RegisterSendRtpHeaderExtension(
+          kRtpExtensionAbsoluteSendTime, id);
+    }
+  } else {
+    // Disable the extension.
+    absolute_send_time_extension_id_ = kInvalidRtpExtensionId;
+    rtp_rtcp_->DeregisterSendRtpHeaderExtension(
+        kRtpExtensionAbsoluteSendTime);
+    for (std::list<RtpRtcp*>::iterator it = simulcast_rtp_rtcp_.begin();
+         it != simulcast_rtp_rtcp_.end(); it++) {
+      (*it)->DeregisterSendRtpHeaderExtension(
+          kRtpExtensionAbsoluteSendTime);
+    }
+  }
+  return error;
+}
+
+int ViEChannel::SetReceiveAbsoluteSendTimeStatus(bool enable, int id) {
+  if (enable) {
+    return rtp_rtcp_->RegisterReceiveRtpHeaderExtension(
+        kRtpExtensionAbsoluteSendTime, id);
+  } else {
+    return rtp_rtcp_->DeregisterReceiveRtpHeaderExtension(
+        kRtpExtensionAbsoluteSendTime);
+  }
+}
+
 void ViEChannel::SetTransmissionSmoothingStatus(bool enable) {
   assert(paced_sender_ && "No paced sender registered.");
   paced_sender_->SetStatus(enable);
diff --git a/webrtc/video_engine/vie_channel.h b/webrtc/video_engine/vie_channel.h
index 540385f77..489abfb1b 100644
--- a/webrtc/video_engine/vie_channel.h
+++ b/webrtc/video_engine/vie_channel.h
@@ -123,6 +123,8 @@ class ViEChannel
   bool EnableRemb(bool enable);
   int SetSendTimestampOffsetStatus(bool enable, int id);
   int SetReceiveTimestampOffsetStatus(bool enable, int id);
+  int SetSendAbsoluteSendTimeStatus(bool enable, int id);
+  int SetReceiveAbsoluteSendTimeStatus(bool enable, int id);
   void SetTransmissionSmoothingStatus(bool enable);
   int32_t EnableTMMBR(const bool enable);
   int32_t EnableKeyFrameRequestCallback(const bool enable);
@@ -382,6 +384,7 @@ class ViEChannel
   scoped_ptr<RtcpBandwidthObserver> bandwidth_observer_;
   bool rtp_packet_timeout_;
   int send_timestamp_extension_id_;
+  int absolute_send_time_extension_id_;
   bool using_packet_spread_;
 
   Transport* external_transport_;
diff --git a/webrtc/video_engine/vie_encoder.cc b/webrtc/video_engine/vie_encoder.cc
index a3ce9a3b3..845dfb6f8 100644
--- a/webrtc/video_engine/vie_encoder.cc
+++ b/webrtc/video_engine/vie_encoder.cc
@@ -194,13 +194,6 @@ bool ViEEncoder::Init() {
                  "%s RegisterSendPayload failure", __FUNCTION__);
     return false;
   }
-  if (default_rtp_rtcp_->RegisterSendRtpHeaderExtension(
-      kRtpExtensionTransmissionTimeOffset, 1) != 0) {
-    WEBRTC_TRACE(webrtc::kTraceError, webrtc::kTraceVideo,
-                 ViEId(engine_id_, channel_id_),
-                 "%s RegisterSendRtpHeaderExtension failure", __FUNCTION__);
-    return false;
-  }
 #else
   VideoCodec video_codec;
   if (vcm_.Codec(webrtc::kVideoCodecI420, &video_codec) == VCM_OK) {
diff --git a/webrtc/video_engine/vie_rtp_rtcp_impl.cc b/webrtc/video_engine/vie_rtp_rtcp_impl.cc
index 134c9541d..a34af02e6 100644
--- a/webrtc/video_engine/vie_rtp_rtcp_impl.cc
+++ b/webrtc/video_engine/vie_rtp_rtcp_impl.cc
@@ -765,6 +765,53 @@ int ViERTP_RTCPImpl::SetReceiveTimestampOffsetStatus(int video_channel,
   return 0;
 }
 
+int ViERTP_RTCPImpl::SetSendAbsoluteSendTimeStatus(int video_channel,
+                                                   bool enable,
+                                                   int id) {
+  WEBRTC_TRACE(kTraceApiCall, kTraceVideo,
+               ViEId(shared_data_->instance_id(), video_channel),
+               "ViERTP_RTCPImpl::SetSendAbsoluteSendTimeStatus(%d, %d, %d)",
+               video_channel, enable, id);
+
+  ViEChannelManagerScoped cs(*(shared_data_->channel_manager()));
+  ViEChannel* vie_channel = cs.Channel(video_channel);
+  if (!vie_channel) {
+    WEBRTC_TRACE(kTraceError, kTraceVideo,
+                 ViEId(shared_data_->instance_id(), video_channel),
+                 "%s: Channel %d doesn't exist", __FUNCTION__, video_channel);
+    shared_data_->SetLastError(kViERtpRtcpInvalidChannelId);
+    return -1;
+  }
+  if (vie_channel->SetSendAbsoluteSendTimeStatus(enable, id) != 0) {
+    shared_data_->SetLastError(kViERtpRtcpUnknownError);
+    return -1;
+  }
+  return 0;
+}
+
+int ViERTP_RTCPImpl::SetReceiveAbsoluteSendTimeStatus(int video_channel,
+                                                      bool enable,
+                                                      int id) {
+  WEBRTC_TRACE(kTraceApiCall, kTraceVideo,
+               ViEId(shared_data_->instance_id(), video_channel),
+               "ViERTP_RTCPImpl::SetReceiveAbsoluteSendTimeStatus(%d, %d, %d)",
+               video_channel, enable, id);
+  ViEChannelManagerScoped cs(*(shared_data_->channel_manager()));
+  ViEChannel* vie_channel = cs.Channel(video_channel);
+  if (!vie_channel) {
+    WEBRTC_TRACE(kTraceError, kTraceVideo,
+                 ViEId(shared_data_->instance_id(), video_channel),
+                 "%s: Channel %d doesn't exist", __FUNCTION__, video_channel);
+    shared_data_->SetLastError(kViERtpRtcpInvalidChannelId);
+    return -1;
+  }
+  if (vie_channel->SetReceiveAbsoluteSendTimeStatus(enable, id) != 0) {
+    shared_data_->SetLastError(kViERtpRtcpUnknownError);
+    return -1;
+  }
+  return 0;
+}
+
 int ViERTP_RTCPImpl::SetTransmissionSmoothingStatus(int video_channel,
                                                     bool enable) {
   WEBRTC_TRACE(kTraceApiCall, kTraceVideo,
diff --git a/webrtc/video_engine/vie_rtp_rtcp_impl.h b/webrtc/video_engine/vie_rtp_rtcp_impl.h
index fb8bd542e..9af4b0c2b 100644
--- a/webrtc/video_engine/vie_rtp_rtcp_impl.h
+++ b/webrtc/video_engine/vie_rtp_rtcp_impl.h
@@ -82,6 +82,12 @@ class ViERTP_RTCPImpl
   virtual int SetReceiveTimestampOffsetStatus(int video_channel,
                                               bool enable,
                                               int id);
+  virtual int SetSendAbsoluteSendTimeStatus(int video_channel,
+                                            bool enable,
+                                            int id);
+  virtual int SetReceiveAbsoluteSendTimeStatus(int video_channel,
+                                               bool enable,
+                                               int id);
   virtual int SetTransmissionSmoothingStatus(int video_channel, bool enable);
   virtual int GetReceivedRTCPStatistics(const int video_channel,
                                         uint16_t& fraction_lost,