diff --git a/talk/app/webrtc/java/android/org/webrtc/VideoRendererGui.java b/talk/app/webrtc/java/android/org/webrtc/VideoRendererGui.java
index 4ad8ccc..0f616c9 100644
--- a/talk/app/webrtc/java/android/org/webrtc/VideoRendererGui.java
+++ b/talk/app/webrtc/java/android/org/webrtc/VideoRendererGui.java
@@ -271,15 +271,15 @@
 
     // Mapping array from original UV mapping to the rotated mapping. The number
     // is the position where the original UV coordination should be mapped
-    // to. (0,1) is the left top coord. (2,3) is the top bottom. (4,5) is the
-    // right top. (6,7) is the right bottom. Note that this is the coordination
-    // that got rotated. For example, using the original left bottom (2,3) as
-    // the top left (0,1) means 90 degree clockwise rotation.
+    // to. (0,1) is the top left coord. (2,3) is the bottom left. (4,5) is the
+    // top right. (6,7) is the bottom right.
     private static int rotation_matrix[][] =
-      { {0, 1, 2, 3, 4, 5, 6, 7},  //   0 degree
-        {2, 3, 6, 7, 0, 1, 4, 5},  //  90 degree (clockwise)
-        {6, 7, 4, 5, 2, 3, 0, 1},  // 180 degree (clockwise)
-        {4, 5, 0, 1, 6, 7, 2, 3} };// 270 degree (clockwise)
+        { {4, 5, 0, 1, 6, 7, 2, 3},   //  90 degree (clockwise)
+          {6, 7, 4, 5, 2, 3, 0, 1},   // 180 degree (clockwise)
+          {2, 3, 6, 7, 0, 1, 4, 5} }; // 270 degree (clockwise)
+
+    private static int mirror_matrix[] =
+        {4, 1, 6, 3, 0, 5, 2, 7}; // mirrored
 
     private YuvImageRenderer(
         GLSurfaceView surface, int id,
@@ -381,12 +381,21 @@
           }
           if (scalingType == ScalingType.SCALE_ASPECT_FILL) {
             // Need to re-adjust UV coordinates to match display AR.
+            boolean adjustU = true;
+            float ratio = 0;
             if (displayAspectRatio > videoAspectRatio) {
-              texOffsetV = (1.0f - videoAspectRatio / displayAspectRatio) /
+              ratio = (1.0f - videoAspectRatio / displayAspectRatio) /
                   2.0f;
+              adjustU = (rotationDegree == 90 || rotationDegree == 270);
             } else {
-              texOffsetU = (1.0f - displayAspectRatio / videoAspectRatio) /
+              ratio = (1.0f - displayAspectRatio / videoAspectRatio) /
                   2.0f;
+              adjustU = (rotationDegree == 0 || rotationDegree == 180);
+            }
+            if (adjustU) {
+              texOffsetU = ratio;
+            } else {
+              texOffsetV = ratio;
             }
           }
           Log.d(TAG, "  Texture vertices: (" + texLeft + "," + texBottom +
@@ -402,37 +411,59 @@
           Log.d(TAG, "  Texture UV offsets: " + texOffsetU + ", " + texOffsetV);
           float uLeft = texOffsetU;
           float uRight = 1.0f - texOffsetU;
-          if (mirror) {
-            // Swap U coordinates for mirror image.
-            uLeft = 1.0f - texOffsetU;
-            uRight = texOffsetU;
-          }
           float textureCoordinatesFloat[] = new float[] {
-            uLeft, texOffsetV,         // left top
-            uLeft, 1.0f - texOffsetV,  // left bottom
-            uRight, texOffsetV,        // right top
-            uRight, 1.0f - texOffsetV  // right bottom
+            uLeft, texOffsetV,         // top left
+            uLeft, 1.0f - texOffsetV,  // bottom left
+            uRight, texOffsetV,        // top right
+            uRight, 1.0f - texOffsetV  // bottom right
           };
 
-          float textureCoordinatesRotatedFloat[];
-          if (rotationDegree == 0) {
-            textureCoordinatesRotatedFloat = textureCoordinatesFloat;
-          } else {
-            textureCoordinatesRotatedFloat =
-              new float[textureCoordinatesFloat.length];
-            int index = rotationDegree / 90;
-            for(int i = 0; i < textureCoordinatesFloat.length; i++) {
-              textureCoordinatesRotatedFloat[rotation_matrix[index][i]] =
-                textureCoordinatesFloat[i];
-            }
-          }
+          // Rotation needs to be done before mirroring.
+          textureCoordinatesFloat = applyRotation(textureCoordinatesFloat,
+                                                  rotationDegree);
+          textureCoordinatesFloat = applyMirror(textureCoordinatesFloat,
+                                                mirror);
           textureCoords =
-            directNativeFloatBuffer(textureCoordinatesRotatedFloat);
+              directNativeFloatBuffer(textureCoordinatesFloat);
         }
         updateTextureProperties = false;
       }
     }
 
+
+    private float[] applyMirror(float textureCoordinatesFloat[],
+                                boolean mirror) {
+      if (!mirror) {
+        return textureCoordinatesFloat;
+      }
+
+      return applyMatrixOperation(textureCoordinatesFloat,
+                                  mirror_matrix);
+    }
+
+    private float[] applyRotation(float textureCoordinatesFloat[],
+                                  int rotationDegree) {
+      if (rotationDegree == 0) {
+        return textureCoordinatesFloat;
+      }
+
+      int index = rotationDegree / 90 - 1;
+      return applyMatrixOperation(textureCoordinatesFloat,
+                                  rotation_matrix[index]);
+    }
+
+    private float[] applyMatrixOperation(float textureCoordinatesFloat[],
+                                         int matrix_operation[]) {
+      float textureCoordinatesModifiedFloat[] =
+          new float[textureCoordinatesFloat.length];
+
+      for(int i = 0; i < textureCoordinatesFloat.length; i++) {
+        textureCoordinatesModifiedFloat[matrix_operation[i]] =
+            textureCoordinatesFloat[i];
+      }
+      return textureCoordinatesModifiedFloat;
+    }
+
     private void draw() {
       if (!seenFrame) {
         // No frame received yet - nothing to render.
diff --git a/talk/media/base/videocapturer.cc b/talk/media/base/videocapturer.cc
index bed3b0c..653e793 100644
--- a/talk/media/base/videocapturer.cc
+++ b/talk/media/base/videocapturer.cc
@@ -254,6 +254,8 @@
   return Pause(false);
 }
 
+// Note that the last caller decides whether rotation should be applied if there
+// are multiple send streams using the same camera.
 bool VideoCapturer::SetApplyRotation(bool enable) {
   apply_rotation_ = enable;
   if (frame_factory_) {
diff --git a/talk/media/base/videoframe.h b/talk/media/base/videoframe.h
index 5b1663c..0aac645 100644
--- a/talk/media/base/videoframe.h
+++ b/talk/media/base/videoframe.h
@@ -83,8 +83,10 @@
   }
 
   // Basic accessors.
+  // Note this is the width and height without rotation applied.
   virtual size_t GetWidth() const = 0;
   virtual size_t GetHeight() const = 0;
+
   size_t GetChromaWidth() const { return (GetWidth() + 1) / 2; }
   size_t GetChromaHeight() const { return (GetHeight() + 1) / 2; }
   size_t GetChromaSize() const { return GetUPitch() * GetChromaHeight(); }
diff --git a/talk/media/webrtc/webrtcvideocapturer.cc b/talk/media/webrtc/webrtcvideocapturer.cc
index 0e8f56b..956356f 100644
--- a/talk/media/webrtc/webrtcvideocapturer.cc
+++ b/talk/media/webrtc/webrtcvideocapturer.cc
@@ -44,6 +44,7 @@
 
 #include "webrtc/base/win32.h"  // Need this to #include the impl files.
 #include "webrtc/modules/video_capture/include/video_capture_factory.h"
+#include "webrtc/system_wrappers/interface/field_trial.h"
 
 namespace cricket {
 
@@ -264,6 +265,13 @@
 
   assert(module_);
 
+  const std::string group_name =
+      webrtc::field_trial::FindFullName("WebRTC-CVO");
+
+  if (group_name == "Disabled") {
+    return true;
+  }
+
   if (!VideoCapturer::SetApplyRotation(enable)) {
     return false;
   }
diff --git a/talk/media/webrtc/webrtcvideoengine.cc b/talk/media/webrtc/webrtcvideoengine.cc
index 287de72..a103cae 100644
--- a/talk/media/webrtc/webrtcvideoengine.cc
+++ b/talk/media/webrtc/webrtcvideoengine.cc
@@ -425,7 +425,8 @@
     WebRtcVideoFrame cricket_frame(
         webrtc_frame.video_frame_buffer(),
         elapsed_time_ms * rtc::kNumNanosecsPerMillisec,
-        webrtc_frame.render_time_ms() * rtc::kNumNanosecsPerMillisec);
+        webrtc_frame.render_time_ms() * rtc::kNumNanosecsPerMillisec,
+        webrtc_frame.rotation());
     return renderer_->RenderFrame(&cricket_frame) ? 0 : -1;
   }
 
@@ -1161,6 +1162,9 @@
   rtp_header_extensions_.push_back(
       RtpHeaderExtension(kRtpAbsoluteSenderTimeHeaderExtension,
                          kRtpAbsoluteSenderTimeHeaderExtensionDefaultId));
+  rtp_header_extensions_.push_back(
+      RtpHeaderExtension(kRtpVideoRotationHeaderExtension,
+                         kRtpVideoRotationHeaderExtensionDefaultId));
 }
 
 WebRtcVideoEngine::~WebRtcVideoEngine() {
@@ -2832,6 +2836,10 @@
     QueueBlackFrame(ssrc, timestamp,
                     VideoFormat::FpsToInterval(send_codec_->maxFramerate));
   }
+
+  capturer->SetApplyRotation(
+      !FindHeaderExtension(send_extensions_, kRtpVideoRotationHeaderExtension));
+
   return true;
 }
 
@@ -2929,6 +2937,8 @@
       FindHeaderExtension(extensions, kRtpTimestampOffsetHeaderExtension);
   const RtpHeaderExtension* send_time_extension =
       FindHeaderExtension(extensions, kRtpAbsoluteSenderTimeHeaderExtension);
+  const RtpHeaderExtension* cvo_extension =
+      FindHeaderExtension(extensions, kRtpVideoRotationHeaderExtension);
 
   // Loop through all receive channels and enable/disable the extensions.
   for (RecvChannelMap::iterator channel_it = recv_channels_.begin();
@@ -2944,6 +2954,10 @@
         send_time_extension)) {
       return false;
     }
+    if (!SetHeaderExtension(&webrtc::ViERTP_RTCP::SetReceiveVideoRotationStatus,
+                            channel_id, cvo_extension)) {
+      return false;
+    }
   }
 
   receive_extensions_ = extensions;
@@ -2960,6 +2974,8 @@
       FindHeaderExtension(extensions, kRtpTimestampOffsetHeaderExtension);
   const RtpHeaderExtension* send_time_extension =
       FindHeaderExtension(extensions, kRtpAbsoluteSenderTimeHeaderExtension);
+  const RtpHeaderExtension* cvo_extension =
+      FindHeaderExtension(extensions, kRtpVideoRotationHeaderExtension);
 
   // Loop through all send channels and enable/disable the extensions.
   for (SendChannelMap::iterator channel_it = send_channels_.begin();
@@ -2975,6 +2991,10 @@
         send_time_extension)) {
       return false;
     }
+    if (!SetHeaderExtension(&webrtc::ViERTP_RTCP::SetSendVideoRotationStatus,
+                            channel_id, cvo_extension)) {
+      return false;
+    }
   }
 
   if (send_time_extension) {
@@ -2986,6 +3006,14 @@
                             send_time_extension->id);
   }
 
+  // For now assume that all streams want the same CVO setting.
+  // TODO(guoweis): Remove the need for this assumption.
+  for (const auto& kv : send_channels_) {
+    if (kv.second->video_capturer()) {
+      kv.second->video_capturer()->SetApplyRotation(!cvo_extension);
+    }
+  }
+
   send_extensions_ = extensions;
   return true;
 }
@@ -3484,6 +3512,11 @@
       receive_extensions_, kRtpAbsoluteSenderTimeHeaderExtension)) {
     return false;
   }
+  if (!SetHeaderExtension(&webrtc::ViERTP_RTCP::SetReceiveVideoRotationStatus,
+                          channel_id, receive_extensions_,
+                          kRtpVideoRotationHeaderExtension)) {
+    return false;
+  }
 
   if (receiver_report_ssrc_ != kSsrcUnset) {
     if (engine()->vie()->rtp()->SetLocalSSRC(
@@ -3594,6 +3627,12 @@
     return false;
   }
 
+  if (!SetHeaderExtension(&webrtc::ViERTP_RTCP::SetSendVideoRotationStatus,
+                          channel_id, send_extensions_,
+                          kRtpVideoRotationHeaderExtension)) {
+    return false;
+  }
+
   if (engine()->vie()->rtp()->SetTransmissionSmoothingStatus(channel_id,
                                                              true) != 0) {
     LOG_RTCERR2(SetTransmissionSmoothingStatus, channel_id, true);
diff --git a/talk/media/webrtc/webrtcvideoengine2.cc b/talk/media/webrtc/webrtcvideoengine2.cc
index c9781a7..ea1fa71 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -134,6 +134,17 @@
   return out.str();
 }
 
+inline const webrtc::RtpExtension* FindHeaderExtension(
+    const std::vector<webrtc::RtpExtension>& extensions,
+    const std::string& name) {
+  for (const auto& kv : extensions) {
+    if (kv.name == name) {
+      return &kv;
+    }
+  }
+  return NULL;
+}
+
 // Merges two fec configs and logs an error if a conflict arises
 // such that merging in diferent order would trigger a diferent output.
 static void MergeFecConfig(const webrtc::FecConfig& other,
@@ -368,6 +379,9 @@
   rtp_header_extensions_.push_back(
       RtpHeaderExtension(kRtpAbsoluteSenderTimeHeaderExtension,
                          kRtpAbsoluteSenderTimeHeaderExtensionDefaultId));
+  rtp_header_extensions_.push_back(
+      RtpHeaderExtension(kRtpVideoRotationHeaderExtension,
+                         kRtpVideoRotationHeaderExtensionDefaultId));
 }
 
 WebRtcVideoEngine2::~WebRtcVideoEngine2() {
@@ -1135,7 +1149,16 @@
     LOG(LS_ERROR) << "No sending stream on ssrc " << ssrc;
     return false;
   }
-  return send_streams_[ssrc]->SetCapturer(capturer);
+  if (!send_streams_[ssrc]->SetCapturer(capturer)) {
+    return false;
+  }
+
+  if (capturer) {
+    capturer->SetApplyRotation(
+        !FindHeaderExtension(send_rtp_extensions_,
+                             kRtpVideoRotationHeaderExtension));
+  }
+  return true;
 }
 
 bool WebRtcVideoChannel2::SendIntraFrame() {
@@ -1258,12 +1281,16 @@
 
   send_rtp_extensions_ = filtered_extensions;
 
+  const webrtc::RtpExtension* cvo_extension = FindHeaderExtension(
+      send_rtp_extensions_, kRtpVideoRotationHeaderExtension);
+
   rtc::CritScope stream_lock(&stream_crit_);
   for (std::map<uint32, WebRtcVideoSendStream*>::iterator it =
            send_streams_.begin();
        it != send_streams_.end();
        ++it) {
     it->second->SetRtpExtensions(send_rtp_extensions_);
+    it->second->SetApplyRotation(!cvo_extension);
   }
   return true;
 }
@@ -1580,6 +1607,15 @@
   return ssrcs_;
 }
 
+void WebRtcVideoChannel2::WebRtcVideoSendStream::SetApplyRotation(
+    bool apply_rotation) {
+  rtc::CritScope cs(&lock_);
+  if (capturer_ == NULL)
+    return;
+
+  capturer_->SetApplyRotation(apply_rotation);
+}
+
 void WebRtcVideoChannel2::WebRtcVideoSendStream::SetOptions(
     const VideoOptions& options) {
   rtc::CritScope cs(&lock_);
@@ -2121,7 +2157,7 @@
   const WebRtcVideoFrame render_frame(
       frame.video_frame_buffer(),
       elapsed_time_ms * rtc::kNumNanosecsPerMillisec,
-      frame.render_time_ms() * rtc::kNumNanosecsPerMillisec);
+      frame.render_time_ms() * rtc::kNumNanosecsPerMillisec, frame.rotation());
   renderer_->RenderFrame(&render_frame);
 }
 
diff --git a/talk/media/webrtc/webrtcvideoengine2.h b/talk/media/webrtc/webrtcvideoengine2.h
index a04d1e5..cd13a01 100644
--- a/talk/media/webrtc/webrtcvideoengine2.h
+++ b/talk/media/webrtc/webrtcvideoengine2.h
@@ -284,6 +284,8 @@
     void MuteStream(bool mute);
     bool DisconnectCapturer();
 
+    void SetApplyRotation(bool apply_rotation);
+
     void Start();
     void Stop();
 
diff --git a/talk/media/webrtc/webrtcvideoengine2_unittest.cc b/talk/media/webrtc/webrtcvideoengine2_unittest.cc
index cbf516d..aabefd6 100644
--- a/talk/media/webrtc/webrtcvideoengine2_unittest.cc
+++ b/talk/media/webrtc/webrtcvideoengine2_unittest.cc
@@ -530,6 +530,82 @@
   FAIL() << "Absolute Sender Time extension not in header-extension list.";
 }
 
+TEST_F(WebRtcVideoEngine2Test, SupportsVideoRotationHeaderExtension) {
+  std::vector<RtpHeaderExtension> extensions = engine_.rtp_header_extensions();
+  ASSERT_FALSE(extensions.empty());
+  for (size_t i = 0; i < extensions.size(); ++i) {
+    if (extensions[i].uri == kRtpVideoRotationHeaderExtension) {
+      EXPECT_EQ(kRtpVideoRotationHeaderExtensionDefaultId, extensions[i].id);
+      return;
+    }
+  }
+  FAIL() << "Video Rotation extension not in header-extension list.";
+}
+
+TEST_F(WebRtcVideoEngine2Test, CVOSetHeaderExtensionBeforeCapturer) {
+  // Allocate the capturer first to prevent early destruction before channel's
+  // dtor is called.
+  cricket::FakeVideoCapturer capturer;
+
+  cricket::FakeWebRtcVideoEncoderFactory encoder_factory;
+  encoder_factory.AddSupportedVideoCodecType(webrtc::kVideoCodecVP8, "VP8");
+  std::vector<cricket::VideoCodec> codecs;
+  codecs.push_back(kVp8Codec);
+
+  rtc::scoped_ptr<VideoMediaChannel> channel(
+      SetUpForExternalEncoderFactory(&encoder_factory, codecs));
+  EXPECT_TRUE(channel->AddSendStream(StreamParams::CreateLegacy(kSsrc)));
+
+  // Add CVO extension.
+  const int id = 1;
+  std::vector<cricket::RtpHeaderExtension> extensions;
+  extensions.push_back(
+      cricket::RtpHeaderExtension(kRtpVideoRotationHeaderExtension, id));
+  EXPECT_TRUE(channel->SetSendRtpHeaderExtensions(extensions));
+
+  // Set capturer.
+  EXPECT_TRUE(channel->SetCapturer(kSsrc, &capturer));
+
+  // Verify capturer has turned off applying rotation.
+  EXPECT_FALSE(capturer.GetApplyRotation());
+
+  // Verify removing header extension turns on applying rotation.
+  extensions.clear();
+  EXPECT_TRUE(channel->SetSendRtpHeaderExtensions(extensions));
+  EXPECT_TRUE(capturer.GetApplyRotation());
+}
+
+TEST_F(WebRtcVideoEngine2Test, CVOSetHeaderExtensionAfterCapturer) {
+  cricket::FakeVideoCapturer capturer;
+
+  cricket::FakeWebRtcVideoEncoderFactory encoder_factory;
+  encoder_factory.AddSupportedVideoCodecType(webrtc::kVideoCodecVP8, "VP8");
+  std::vector<cricket::VideoCodec> codecs;
+  codecs.push_back(kVp8Codec);
+
+  rtc::scoped_ptr<VideoMediaChannel> channel(
+      SetUpForExternalEncoderFactory(&encoder_factory, codecs));
+  EXPECT_TRUE(channel->AddSendStream(StreamParams::CreateLegacy(kSsrc)));
+
+  // Set capturer.
+  EXPECT_TRUE(channel->SetCapturer(kSsrc, &capturer));
+
+  // Add CVO extension.
+  const int id = 1;
+  std::vector<cricket::RtpHeaderExtension> extensions;
+  extensions.push_back(
+      cricket::RtpHeaderExtension(kRtpVideoRotationHeaderExtension, id));
+  EXPECT_TRUE(channel->SetSendRtpHeaderExtensions(extensions));
+
+  // Verify capturer has turned off applying rotation.
+  EXPECT_FALSE(capturer.GetApplyRotation());
+
+  // Verify removing header extension turns on applying rotation.
+  extensions.clear();
+  EXPECT_TRUE(channel->SetSendRtpHeaderExtensions(extensions));
+  EXPECT_TRUE(capturer.GetApplyRotation());
+}
+
 TEST_F(WebRtcVideoEngine2Test, SetSendFailsBeforeSettingCodecs) {
   engine_.Init(rtc::Thread::Current());
   rtc::scoped_ptr<VideoMediaChannel> channel(
@@ -1198,21 +1274,34 @@
                                  webrtc::RtpExtension::kAbsSendTime);
 }
 
+// Test support for video rotation header extension.
+TEST_F(WebRtcVideoChannel2Test, SendVideoRotationHeaderExtensions) {
+  TestSetSendRtpHeaderExtensions(kRtpVideoRotationHeaderExtension,
+                                 webrtc::RtpExtension::kVideoRotation);
+}
+TEST_F(WebRtcVideoChannel2Test, RecvVideoRotationHeaderExtensions) {
+  TestSetRecvRtpHeaderExtensions(kRtpVideoRotationHeaderExtension,
+                                 webrtc::RtpExtension::kVideoRotation);
+}
+
 TEST_F(WebRtcVideoChannel2Test, IdenticalSendExtensionsDoesntRecreateStream) {
   const int kTOffsetId = 1;
   const int kAbsSendTimeId = 2;
+  const int kVideoRotationId = 3;
   std::vector<cricket::RtpHeaderExtension> extensions;
   extensions.push_back(cricket::RtpHeaderExtension(
       kRtpAbsoluteSenderTimeHeaderExtension, kAbsSendTimeId));
   extensions.push_back(cricket::RtpHeaderExtension(
       kRtpTimestampOffsetHeaderExtension, kTOffsetId));
+  extensions.push_back(cricket::RtpHeaderExtension(
+      kRtpVideoRotationHeaderExtension, kVideoRotationId));
 
   EXPECT_TRUE(channel_->SetSendRtpHeaderExtensions(extensions));
   FakeVideoSendStream* send_stream =
       AddSendStream(cricket::StreamParams::CreateLegacy(123));
 
   EXPECT_EQ(1, fake_call_->GetNumCreatedSendStreams());
-  ASSERT_EQ(2u, send_stream->GetConfig().rtp.extensions.size());
+  ASSERT_EQ(3u, send_stream->GetConfig().rtp.extensions.size());
 
   // Setting the same extensions (even if in different order) shouldn't
   // reallocate the stream.
@@ -1231,18 +1320,21 @@
 TEST_F(WebRtcVideoChannel2Test, IdenticalRecvExtensionsDoesntRecreateStream) {
   const int kTOffsetId = 1;
   const int kAbsSendTimeId = 2;
+  const int kVideoRotationId = 3;
   std::vector<cricket::RtpHeaderExtension> extensions;
   extensions.push_back(cricket::RtpHeaderExtension(
       kRtpAbsoluteSenderTimeHeaderExtension, kAbsSendTimeId));
   extensions.push_back(cricket::RtpHeaderExtension(
       kRtpTimestampOffsetHeaderExtension, kTOffsetId));
+  extensions.push_back(cricket::RtpHeaderExtension(
+      kRtpVideoRotationHeaderExtension, kVideoRotationId));
 
   EXPECT_TRUE(channel_->SetRecvRtpHeaderExtensions(extensions));
   FakeVideoReceiveStream* send_stream =
       AddRecvStream(cricket::StreamParams::CreateLegacy(123));
 
   EXPECT_EQ(1, fake_call_->GetNumCreatedReceiveStreams());
-  ASSERT_EQ(2u, send_stream->GetConfig().rtp.extensions.size());
+  ASSERT_EQ(3u, send_stream->GetConfig().rtp.extensions.size());
 
   // Setting the same extensions (even if in different order) shouldn't
   // reallocate the stream.
diff --git a/talk/media/webrtc/webrtcvideoengine_unittest.cc b/talk/media/webrtc/webrtcvideoengine_unittest.cc
index edfa53a..e6ac7c1 100644
--- a/talk/media/webrtc/webrtcvideoengine_unittest.cc
+++ b/talk/media/webrtc/webrtcvideoengine_unittest.cc
@@ -50,6 +50,7 @@
 
 using cricket::kRtpTimestampOffsetHeaderExtension;
 using cricket::kRtpAbsoluteSenderTimeHeaderExtension;
+using cricket::kRtpVideoRotationHeaderExtension;
 
 static const cricket::VideoCodec kVP8Codec720p(100, "VP8", 1280, 720, 30, 0);
 static const cricket::VideoCodec kVP8Codec360p(100, "VP8", 640, 360, 30, 0);
@@ -1005,6 +1006,14 @@
   TestSetRecvRtpHeaderExtensions(kRtpAbsoluteSenderTimeHeaderExtension);
 }
 
+// Test support for Coordination of Video Orientation (CVO) header extension.
+TEST_F(WebRtcVideoEngineTestFake, SendVideoRotationHeaderExtensions) {
+  TestSetSendRtpHeaderExtensions(kRtpVideoRotationHeaderExtension);
+}
+TEST_F(WebRtcVideoEngineTestFake, RecvVideoRotationHeaderExtensions) {
+  TestSetRecvRtpHeaderExtensions(kRtpVideoRotationHeaderExtension);
+}
+
 TEST_F(WebRtcVideoEngineTestFake, LeakyBucketTest) {
   EXPECT_TRUE(SetupEngine());
 
diff --git a/talk/media/webrtc/webrtcvideoframe.cc b/talk/media/webrtc/webrtcvideoframe.cc
index 14118e1..e308a73 100644
--- a/talk/media/webrtc/webrtcvideoframe.cc
+++ b/talk/media/webrtc/webrtcvideoframe.cc
@@ -49,6 +49,19 @@
 WebRtcVideoFrame::WebRtcVideoFrame(
     const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
     int64_t elapsed_time_ns,
+    int64_t time_stamp_ns,
+    webrtc::VideoRotation rotation)
+    : video_frame_buffer_(buffer),
+      pixel_width_(1),
+      pixel_height_(1),
+      elapsed_time_ns_(elapsed_time_ns),
+      time_stamp_ns_(time_stamp_ns),
+      rotation_(rotation) {
+}
+
+WebRtcVideoFrame::WebRtcVideoFrame(
+    const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
+    int64_t elapsed_time_ns,
     int64_t time_stamp_ns)
     : video_frame_buffer_(buffer),
       pixel_width_(1),
@@ -62,7 +75,8 @@
                                    int width,
                                    int height,
                                    int64_t elapsed_time_ns,
-                                   int64_t time_stamp_ns)
+                                   int64_t time_stamp_ns,
+                                   webrtc::VideoRotation rotation)
     : video_frame_buffer_(
           new rtc::RefCountedObject<webrtc::TextureBuffer>(handle,
                                                            width,
@@ -71,7 +85,7 @@
       pixel_height_(1),
       elapsed_time_ns_(elapsed_time_ns),
       time_stamp_ns_(time_stamp_ns),
-      rotation_(webrtc::kVideoRotation_0) {
+      rotation_(rotation) {
 }
 
 WebRtcVideoFrame::~WebRtcVideoFrame() {}
@@ -176,10 +190,9 @@
 
 VideoFrame* WebRtcVideoFrame::Copy() const {
   WebRtcVideoFrame* new_frame = new WebRtcVideoFrame(
-      video_frame_buffer_, elapsed_time_ns_, time_stamp_ns_);
+      video_frame_buffer_, elapsed_time_ns_, time_stamp_ns_, rotation_);
   new_frame->pixel_width_ = pixel_width_;
   new_frame->pixel_height_ = pixel_height_;
-  new_frame->rotation_ = rotation_;
   return new_frame;
 }
 
diff --git a/talk/media/webrtc/webrtcvideoframe.h b/talk/media/webrtc/webrtcvideoframe.h
index d4380b5..a1872c5 100644
--- a/talk/media/webrtc/webrtcvideoframe.h
+++ b/talk/media/webrtc/webrtcvideoframe.h
@@ -44,12 +44,20 @@
   WebRtcVideoFrame();
   WebRtcVideoFrame(const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
                    int64_t elapsed_time_ns,
+                   int64_t time_stamp_ns,
+                   webrtc::VideoRotation rotation);
+
+  // TODO(guoweis): Remove this when chrome code base is updated.
+  WebRtcVideoFrame(const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& buffer,
+                   int64_t elapsed_time_ns,
                    int64_t time_stamp_ns);
+
   WebRtcVideoFrame(webrtc::NativeHandle* handle,
                    int width,
                    int height,
                    int64_t elapsed_time_ns,
-                   int64_t time_stamp_ns);
+                   int64_t time_stamp_ns,
+                   webrtc::VideoRotation rotation);
   ~WebRtcVideoFrame();
 
   // Creates a frame from a raw sample with FourCC "format" and size "w" x "h".
diff --git a/talk/media/webrtc/webrtcvideoframe_unittest.cc b/talk/media/webrtc/webrtcvideoframe_unittest.cc
index bbf5d42..8cbe479 100644
--- a/talk/media/webrtc/webrtcvideoframe_unittest.cc
+++ b/talk/media/webrtc/webrtcvideoframe_unittest.cc
@@ -340,7 +340,8 @@
 
 TEST_F(WebRtcVideoFrameTest, TextureInitialValues) {
   NativeHandleImpl handle;
-  cricket::WebRtcVideoFrame frame(&handle, 640, 480, 100, 200);
+  cricket::WebRtcVideoFrame frame(&handle, 640, 480, 100, 200,
+                                  webrtc::kVideoRotation_0);
   EXPECT_EQ(&handle, frame.GetNativeHandle());
   EXPECT_EQ(640u, frame.GetWidth());
   EXPECT_EQ(480u, frame.GetHeight());
@@ -354,7 +355,8 @@
 
 TEST_F(WebRtcVideoFrameTest, CopyTextureFrame) {
   NativeHandleImpl handle;
-  cricket::WebRtcVideoFrame frame1(&handle, 640, 480, 100, 200);
+  cricket::WebRtcVideoFrame frame1(&handle, 640, 480, 100, 200,
+                                   webrtc::kVideoRotation_0);
   cricket::VideoFrame* frame2 = frame1.Copy();
   EXPECT_EQ(frame1.GetNativeHandle(), frame2->GetNativeHandle());
   EXPECT_EQ(frame1.GetWidth(), frame2->GetWidth());
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
index e8109fa..8605925 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
@@ -34,6 +34,17 @@
 
 int32_t RtpHeaderExtensionMap::Register(const RTPExtensionType type,
                                         const uint8_t id) {
+  return Register(type, id, true);
+}
+
+int32_t RtpHeaderExtensionMap::RegisterInactive(const RTPExtensionType type,
+                                                const uint8_t id) {
+  return Register(type, id, false);
+}
+
+int32_t RtpHeaderExtensionMap::Register(const RTPExtensionType type,
+                                        const uint8_t id,
+                                        bool active) {
   if (id < 1 || id > 14) {
     return -1;
   }
@@ -47,12 +58,24 @@
     }
     // This extension type is already registered with this id,
     // so return success.
+    it->second->active = active;
     return 0;
   }
-  extensionMap_[id] = new HeaderExtension(type);
+  extensionMap_[id] = new HeaderExtension(type, active);
   return 0;
 }
 
+bool RtpHeaderExtensionMap::SetActive(const RTPExtensionType type,
+                                      bool active) {
+  for (auto& kv : extensionMap_) {
+    if (kv.second->type == type) {
+      kv.second->active = active;
+      return true;
+    }
+  }
+  return false;
+}
+
 int32_t RtpHeaderExtensionMap::Deregister(const RTPExtensionType type) {
   uint8_t id;
   if (GetId(type, &id) != 0) {
@@ -113,7 +136,9 @@
       extensionMap_.begin();
   while (it != extensionMap_.end()) {
     HeaderExtension* extension = it->second;
-    length += extension->length;
+    if (extension->active) {
+      length += extension->length;
+    }
     it++;
   }
   // Add RTP extension header length.
@@ -140,8 +165,11 @@
   while (it != extensionMap_.end()) {
     HeaderExtension* extension = it->second;
     if (extension->type == type) {
+      if (!extension->active) {
+        return -1;
+      }
       break;
-    } else {
+    } else if (extension->active) {
       length += extension->length;
     }
     it++;
@@ -150,17 +178,23 @@
 }
 
 int32_t RtpHeaderExtensionMap::Size() const {
-  return extensionMap_.size();
+  int32_t count = 0;
+  for (auto& kv : extensionMap_) {
+    if (kv.second->active) {
+      count++;
+    }
+  }
+  return count;
 }
 
 RTPExtensionType RtpHeaderExtensionMap::First() const {
-  std::map<uint8_t, HeaderExtension*>::const_iterator it =
-      extensionMap_.begin();
-  if (it == extensionMap_.end()) {
-     return kRtpExtensionNone;
+  for (auto& kv : extensionMap_) {
+    if (kv.second->active) {
+      return kv.second->type;
+    }
   }
-  HeaderExtension* extension = it->second;
-  return extension->type;
+
+  return kRtpExtensionNone;
 }
 
 RTPExtensionType RtpHeaderExtensionMap::Next(RTPExtensionType type) const {
@@ -170,15 +204,16 @@
   }
   std::map<uint8_t, HeaderExtension*>::const_iterator it =
       extensionMap_.find(id);
-  if (it == extensionMap_.end()) {
+  if (it == extensionMap_.end() || !it->second->active) {
     return kRtpExtensionNone;
   }
-  it++;
-  if (it == extensionMap_.end()) {
-    return kRtpExtensionNone;
+  while ((++it) != extensionMap_.end()) {
+    if (it->second->active) {
+      return it->second->type;
+    }
   }
-  HeaderExtension* extension = it->second;
-  return extension->type;
+
+  return kRtpExtensionNone;
 }
 
 void RtpHeaderExtensionMap::GetCopy(RtpHeaderExtensionMap* map) const {
@@ -187,7 +222,7 @@
       extensionMap_.begin();
   while (it != extensionMap_.end()) {
     HeaderExtension* extension = it->second;
-    map->Register(extension->type, it->first);
+    map->Register(extension->type, it->first, extension->active);
     it++;
   }
 }
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.h b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.h
index cb49ea7..7be3c2e 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.h
@@ -29,8 +29,16 @@
 
 struct HeaderExtension {
   HeaderExtension(RTPExtensionType extension_type)
-    : type(extension_type),
-      length(0) {
+      : type(extension_type), length(0), active(true) {
+    Init();
+  }
+
+  HeaderExtension(RTPExtensionType extension_type, bool active)
+      : type(extension_type), length(0), active(active) {
+    Init();
+  }
+
+  void Init() {
     // TODO(solenberg): Create handler classes for header extensions so we can
     // get rid of switches like these as well as handling code spread out all
     // over.
@@ -57,6 +65,7 @@
 
   const RTPExtensionType type;
   uint8_t length;
+  bool active;
 };
 
 class RtpHeaderExtensionMap {
@@ -68,6 +77,13 @@
 
   int32_t Register(const RTPExtensionType type, const uint8_t id);
 
+  // Active is a concept for a registered rtp header extension which doesn't
+  // take effect yet until being activated. Inactive RTP header extensions do
+  // not take effect and should not be included in size calculations until they
+  // are activated.
+  int32_t RegisterInactive(const RTPExtensionType type, const uint8_t id);
+  bool SetActive(const RTPExtensionType type, bool active);
+
   int32_t Deregister(const RTPExtensionType type);
 
   bool IsRegistered(RTPExtensionType type) const;
@@ -76,6 +92,10 @@
 
   int32_t GetId(const RTPExtensionType type, uint8_t* id) const;
 
+  //
+  // Methods below ignore any inactive rtp header extensions.
+  //
+
   size_t GetTotalLengthInBytes() const;
 
   int32_t GetLengthUntilBlockStartInBytes(const RTPExtensionType type) const;
@@ -89,6 +109,7 @@
   RTPExtensionType Next(RTPExtensionType type) const;
 
  private:
+  int32_t Register(const RTPExtensionType type, const uint8_t id, bool active);
   std::map<uint8_t, HeaderExtension*> extensionMap_;
 };
 }
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
index d8387e8..520cf7a 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extension_unittest.cc
@@ -35,9 +35,16 @@
 TEST_F(RtpHeaderExtensionTest, Register) {
   EXPECT_EQ(0, map_.Size());
   EXPECT_EQ(0, map_.Register(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_TRUE(map_.IsRegistered(kRtpExtensionTransmissionTimeOffset));
   EXPECT_EQ(1, map_.Size());
   EXPECT_EQ(0, map_.Deregister(kRtpExtensionTransmissionTimeOffset));
   EXPECT_EQ(0, map_.Size());
+
+  EXPECT_EQ(0, map_.RegisterInactive(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_EQ(0, map_.Size());
+  EXPECT_TRUE(map_.IsRegistered(kRtpExtensionTransmissionTimeOffset));
+  EXPECT_TRUE(map_.SetActive(kRtpExtensionTransmissionTimeOffset, true));
+  EXPECT_EQ(1, map_.Size());
 }
 
 TEST_F(RtpHeaderExtensionTest, RegisterIllegalArg) {
@@ -56,10 +63,14 @@
 TEST_F(RtpHeaderExtensionTest, NonUniqueId) {
   EXPECT_EQ(0, map_.Register(kRtpExtensionTransmissionTimeOffset, kId));
   EXPECT_EQ(-1, map_.Register(kRtpExtensionAudioLevel, kId));
+  EXPECT_EQ(-1, map_.RegisterInactive(kRtpExtensionAudioLevel, kId));
 }
 
 TEST_F(RtpHeaderExtensionTest, GetTotalLength) {
   EXPECT_EQ(0u, map_.GetTotalLengthInBytes());
+  EXPECT_EQ(0, map_.RegisterInactive(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_EQ(0u, map_.GetTotalLengthInBytes());
+
   EXPECT_EQ(0, map_.Register(kRtpExtensionTransmissionTimeOffset, kId));
   EXPECT_EQ(kRtpOneByteHeaderLength + kTransmissionTimeOffsetLength,
             map_.GetTotalLengthInBytes());
@@ -68,7 +79,11 @@
 TEST_F(RtpHeaderExtensionTest, GetLengthUntilBlockStart) {
   EXPECT_EQ(-1, map_.GetLengthUntilBlockStartInBytes(
       kRtpExtensionTransmissionTimeOffset));
-  EXPECT_EQ(0, map_.Register(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_EQ(0, map_.RegisterInactive(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_EQ(-1, map_.GetLengthUntilBlockStartInBytes(
+                    kRtpExtensionTransmissionTimeOffset));
+
+  EXPECT_TRUE(map_.SetActive(kRtpExtensionTransmissionTimeOffset, true));
   EXPECT_EQ(static_cast<int>(kRtpOneByteHeaderLength),
             map_.GetLengthUntilBlockStartInBytes(
                 kRtpExtensionTransmissionTimeOffset));
@@ -96,7 +111,11 @@
   EXPECT_EQ(kRtpExtensionNone, map_.First());
   EXPECT_EQ(kRtpExtensionNone, map_.Next(kRtpExtensionTransmissionTimeOffset));
 
-  EXPECT_EQ(0, map_.Register(kRtpExtensionTransmissionTimeOffset, kId));
+  EXPECT_EQ(0, map_.RegisterInactive(kRtpExtensionTransmissionTimeOffset, kId));
+
+  EXPECT_EQ(kRtpExtensionNone, map_.First());
+
+  EXPECT_TRUE(map_.SetActive(kRtpExtensionTransmissionTimeOffset, true));
 
   EXPECT_EQ(kRtpExtensionTransmissionTimeOffset, map_.First());
   EXPECT_EQ(kRtpExtensionNone, map_.Next(kRtpExtensionTransmissionTimeOffset));
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc b/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
index 2823868..8d8147c 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
@@ -63,13 +63,6 @@
   const size_t payload_data_length =
       payload_length - rtp_header->header.paddingLength;
 
-  // Retrieve the video rotation information.
-  rtp_header->type.Video.rotation = kVideoRotation_0;
-  if (rtp_header->header.extension.hasVideoRotation) {
-    rtp_header->type.Video.rotation = ConvertCVOByteToVideoRotation(
-        rtp_header->header.extension.videoRotation);
-  }
-
   if (payload == NULL || payload_data_length == 0) {
     return data_callback_->OnReceivedPayloadData(NULL, 0, rtp_header) == 0 ? 0
                                                                            : -1;
@@ -90,6 +83,14 @@
 
   rtp_header->frameType = parsed_payload.frame_type;
   rtp_header->type = parsed_payload.type;
+  rtp_header->type.Video.rotation = kVideoRotation_0;
+
+  // Retrieve the video rotation information.
+  if (rtp_header->header.extension.hasVideoRotation) {
+    rtp_header->type.Video.rotation = ConvertCVOByteToVideoRotation(
+        rtp_header->header.extension.videoRotation);
+  }
+
   return data_callback_->OnReceivedPayloadData(parsed_payload.payload,
                                                parsed_payload.payload_length,
                                                rtp_header) == 0
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
index 35f885a..cb0c6dc 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
@@ -129,6 +129,7 @@
       transmission_time_offset_(0),
       absolute_send_time_(0),
       rotation_(kVideoRotation_0),
+      cvo_mode_(kCVONone),
       transport_sequence_number_(0),
       // NACK.
       nack_byte_count_times_(),
@@ -266,6 +267,10 @@
 int32_t RTPSender::RegisterRtpHeaderExtension(RTPExtensionType type,
                                               uint8_t id) {
   CriticalSectionScoped cs(send_critsect_.get());
+  if (type == kRtpExtensionVideoRotation) {
+    cvo_mode_ = kCVOInactive;
+    return rtp_header_extension_map_.RegisterInactive(type, id);
+  }
   return rtp_header_extension_map_.Register(type, id);
 }
 
@@ -462,6 +467,16 @@
   return 0;
 }
 
+RTPSenderInterface::CVOMode RTPSender::ActivateCVORtpHeaderExtension() {
+  if (cvo_mode_ == kCVOInactive) {
+    CriticalSectionScoped cs(send_critsect_.get());
+    if (rtp_header_extension_map_.SetActive(kRtpExtensionVideoRotation, true)) {
+      cvo_mode_ = kCVOActivated;
+    }
+  }
+  return cvo_mode_;
+}
+
 int32_t RTPSender::SendOutgoingData(FrameType frame_type,
                                     int8_t payload_type,
                                     uint32_t capture_timestamp,
@@ -1201,8 +1216,7 @@
         block_length = BuildAbsoluteSendTimeExtension(extension_data);
         break;
       case kRtpExtensionVideoRotation:
-        if (marker_bit)
-          block_length = BuildVideoRotationExtension(extension_data);
+        block_length = BuildVideoRotationExtension(extension_data);
         break;
       case kRtpExtensionTransportSequenceNumber:
         block_length = BuildTransportSequenceNumberExtension(extension_data);
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.h b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
index baa067c..61d835d 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
@@ -41,6 +41,14 @@
   RTPSenderInterface() {}
   virtual ~RTPSenderInterface() {}
 
+  enum CVOMode {
+    kCVONone,
+    kCVOInactive,  // CVO rtp header extension is registered but haven't
+                   // received any frame with rotation pending.
+    kCVOActivated,  // CVO rtp header extension will be present in the rtp
+                    // packets.
+  };
+
   virtual uint32_t SSRC() const = 0;
   virtual uint32_t Timestamp() const = 0;
 
@@ -70,6 +78,7 @@
                                    const RTPHeader& rtp_header,
                                    VideoRotation rotation) const = 0;
   virtual bool IsRtpHeaderExtensionRegistered(RTPExtensionType type) = 0;
+  virtual CVOMode ActivateCVORtpHeaderExtension() = 0;
 };
 
 class RTPSender : public RTPSenderInterface {
@@ -285,6 +294,7 @@
   RtpState GetRtpState() const;
   void SetRtxRtpState(const RtpState& rtp_state);
   RtpState GetRtxRtpState() const;
+  CVOMode ActivateCVORtpHeaderExtension() override;
 
  protected:
   int32_t CheckPayloadType(int8_t payload_type, RtpVideoCodecTypes* video_type);
@@ -378,6 +388,7 @@
   int32_t transmission_time_offset_;
   uint32_t absolute_send_time_;
   VideoRotation rotation_;
+  CVOMode cvo_mode_;
   uint16_t transport_sequence_number_;
 
   // NACK
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
index a55ca97..f6ea40b 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
@@ -186,7 +186,6 @@
     }
     ASSERT_TRUE(rtp_parser.Parse(rtp_header, map));
     ASSERT_FALSE(rtp_parser.RTCP());
-    EXPECT_EQ(expect_cvo, rtp_header.markerBit);
     EXPECT_EQ(payload_, rtp_header.payloadType);
     EXPECT_EQ(seq_num, rtp_header.sequenceNumber);
     EXPECT_EQ(kTimestamp, rtp_header.timestamp);
@@ -254,6 +253,7 @@
             rtp_sender_->RtpHeaderExtensionTotalLength());
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionVideoRotation, kVideoRotationExtensionId));
+  EXPECT_TRUE(rtp_sender_->ActivateCVORtpHeaderExtension());
   EXPECT_EQ(RtpUtility::Word32Align(kRtpOneByteHeaderLength +
                                     kTransmissionTimeOffsetLength +
                                     kAbsoluteSendTimeLength +
@@ -286,6 +286,9 @@
   EXPECT_EQ(0u, rtp_sender_->RtpHeaderExtensionTotalLength());
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionVideoRotation, kVideoRotationExtensionId));
+  EXPECT_EQ(0u, rtp_sender_->RtpHeaderExtensionTotalLength());
+
+  EXPECT_TRUE(rtp_sender_->ActivateCVORtpHeaderExtension());
   EXPECT_EQ(
       RtpUtility::Word32Align(kRtpOneByteHeaderLength + kVideoRotationLength),
       rtp_sender_->RtpHeaderExtensionTotalLength());
@@ -424,6 +427,7 @@
   rtp_sender_->SetVideoRotation(kRotation);
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionVideoRotation, kVideoRotationExtensionId));
+  EXPECT_TRUE(rtp_sender_->ActivateCVORtpHeaderExtension());
 
   RtpHeaderExtensionMap map;
   map.Register(kRtpExtensionVideoRotation, kVideoRotationExtensionId);
@@ -447,10 +451,11 @@
 }
 
 // Test CVO header extension is not set when marker bit is false.
-TEST_F(RtpSenderTest, BuildRTPPacketWithVideoRotation_NoMarkerBit) {
+TEST_F(RtpSenderTest, DISABLED_BuildRTPPacketWithVideoRotation_NoMarkerBit) {
   rtp_sender_->SetVideoRotation(kRotation);
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionVideoRotation, kVideoRotationExtensionId));
+  EXPECT_TRUE(rtp_sender_->ActivateCVORtpHeaderExtension());
 
   RtpHeaderExtensionMap map;
   map.Register(kRtpExtensionVideoRotation, kVideoRotationExtensionId);
@@ -1333,13 +1338,15 @@
             rtx_stats.transmitted.TotalBytes());
 }
 
-// Verify that only the last packet of a frame has CVO byte set.
+// Verify that all packets of a frame have CVO byte set.
 TEST_F(RtpSenderVideoTest, SendVideoWithCVO) {
   RTPVideoHeader hdr = {0};
   hdr.rotation = kVideoRotation_90;
 
   EXPECT_EQ(0, rtp_sender_->RegisterRtpHeaderExtension(
                    kRtpExtensionVideoRotation, kVideoRotationExtensionId));
+  EXPECT_TRUE(rtp_sender_->ActivateCVORtpHeaderExtension());
+
   EXPECT_EQ(
       RtpUtility::Word32Align(kRtpOneByteHeaderLength + kVideoRotationLength),
       rtp_sender_->RtpHeaderExtensionTotalLength());
@@ -1351,13 +1358,12 @@
   RtpHeaderExtensionMap map;
   map.Register(kRtpExtensionVideoRotation, kVideoRotationExtensionId);
 
-  // Verify that this packet doesn't have CVO byte.
+  // Verify that this packet does have CVO byte.
   VerifyCVOPacket(
       reinterpret_cast<uint8_t*>(transport_.sent_packets_[0]->data()),
-      transport_.sent_packets_[0]->size(), false, &map, kSeqNum,
-      kVideoRotation_0);
+      transport_.sent_packets_[0]->length(), true, &map, kSeqNum, hdr.rotation);
 
-  // Verify that this packet doesn't have CVO byte.
+  // Verify that this packet does have CVO byte.
   VerifyCVOPacket(
       reinterpret_cast<uint8_t*>(transport_.sent_packets_[1]->data()),
       transport_.sent_packets_[1]->size(), true, &map, kSeqNum + 1,
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
index 2b14cfe..703ae2b 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_video.cc
@@ -301,6 +301,13 @@
                           const size_t payloadSize,
                           const RTPFragmentationHeader* fragmentation,
                           const RTPVideoHeader* rtpHdr) {
+  // Register CVO rtp header extension at the first time when we receive a frame
+  // with pending rotation.
+  RTPSenderInterface::CVOMode cvo_mode = RTPSenderInterface::kCVONone;
+  if (rtpHdr && rtpHdr->rotation != kVideoRotation_0) {
+    cvo_mode = _rtpSender.ActivateCVORtpHeaderExtension();
+  }
+
   uint16_t rtp_header_length = _rtpSender.RTPHeaderLength();
   size_t payload_bytes_to_send = payloadSize;
   const uint8_t* data = payloadData;
@@ -341,13 +348,16 @@
     // packet in each group of packets which make up another type of frame
     // (e.g. a P-Frame) only if the current value is different from the previous
     // value sent.
-    // Here we are adding it to the last packet of every frame at this point.
+    // Here we are adding it to every packet of every frame at this point.
     if (!rtpHdr) {
       assert(!_rtpSender.IsRtpHeaderExtensionRegistered(
           kRtpExtensionVideoRotation));
-    } else if (last) {
+    } else if (cvo_mode == RTPSenderInterface::kCVOActivated) {
       // Checking whether CVO header extension is registered will require taking
       // a lock. It'll be a no-op if it's not registered.
+      // TODO(guoweis): For now, all packets sent will carry the CVO such that
+      // the RTP header length is consistent, although the receiver side will
+      // only exam the packets with market bit set.
       size_t packetSize = payloadSize + rtp_header_length;
       RtpUtility::RtpHeaderParser rtp_parser(dataBuffer, packetSize);
       RTPHeader rtp_header;
diff --git a/webrtc/modules/video_coding/main/source/packet.cc b/webrtc/modules/video_coding/main/source/packet.cc
index dd3743f..fb815c4 100644
--- a/webrtc/modules/video_coding/main/source/packet.cc
+++ b/webrtc/modules/video_coding/main/source/packet.cc
@@ -99,6 +99,9 @@
 }
 
 void VCMPacket::CopyCodecSpecifics(const RTPVideoHeader& videoHeader) {
+  if (markerBit) {
+    codecSpecificHeader.rotation = videoHeader.rotation;
+  }
   switch (videoHeader.codec) {
     case kRtpVideoVp8:
       // Handle all packets within a frame as depending on the previous packet