Unrevert 5590 "description"(=(Auto)update libjingle 61834300->61901702).

BUG=N/A
R=xians@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9009004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5595 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/app/webrtc/mediastreamhandler.cc b/talk/app/webrtc/mediastreamhandler.cc
index ca8e105..ca28cf4 100644
--- a/talk/app/webrtc/mediastreamhandler.cc
+++ b/talk/app/webrtc/mediastreamhandler.cc
@@ -58,7 +58,11 @@
 
 LocalAudioSinkAdapter::LocalAudioSinkAdapter() : sink_(NULL) {}
 
-LocalAudioSinkAdapter::~LocalAudioSinkAdapter() {}
+LocalAudioSinkAdapter::~LocalAudioSinkAdapter() {
+  talk_base::CritScope lock(&lock_);
+  if (sink_)
+    sink_->OnClose();
+}
 
 void LocalAudioSinkAdapter::OnData(const void* audio_data,
                                    int bits_per_sample,
diff --git a/talk/app/webrtc/test/fakeperiodicvideocapturer.h b/talk/app/webrtc/test/fakeperiodicvideocapturer.h
index 7f70ae2..88fd753 100644
--- a/talk/app/webrtc/test/fakeperiodicvideocapturer.h
+++ b/talk/app/webrtc/test/fakeperiodicvideocapturer.h
@@ -56,6 +56,7 @@
   virtual cricket::CaptureState Start(const cricket::VideoFormat& format) {
     cricket::CaptureState state = FakeVideoCapturer::Start(format);
     if (state != cricket::CS_FAILED) {
+      set_enable_video_adapter(false);  // Simplify testing.
       talk_base::Thread::Current()->Post(this, MSG_CREATEFRAME);
     }
     return state;
diff --git a/talk/app/webrtc/webrtcsession_unittest.cc b/talk/app/webrtc/webrtcsession_unittest.cc
index d9ce644..64acad0 100644
--- a/talk/app/webrtc/webrtcsession_unittest.cc
+++ b/talk/app/webrtc/webrtcsession_unittest.cc
@@ -249,7 +249,11 @@
 
 class FakeAudioRenderer : public cricket::AudioRenderer {
  public:
-  FakeAudioRenderer() : channel_id_(-1) {}
+  FakeAudioRenderer() : channel_id_(-1), sink_(NULL) {}
+  virtual ~FakeAudioRenderer() {
+    if (sink_)
+      sink_->OnClose();
+  }
 
   virtual void AddChannel(int channel_id) OVERRIDE {
     ASSERT(channel_id_ == -1);
@@ -259,10 +263,15 @@
     ASSERT(channel_id == channel_id_);
     channel_id_ = -1;
   }
+  virtual void SetSink(Sink* sink) OVERRIDE {
+    sink_ = sink;
+  }
 
   int channel_id() const { return channel_id_; }
+  cricket::AudioRenderer::Sink* sink() const { return sink_; }
  private:
   int channel_id_;
+  cricket::AudioRenderer::Sink* sink_;
 };
 
 class WebRtcSessionTest : public testing::Test {
@@ -2187,13 +2196,39 @@
   EXPECT_TRUE(channel->IsStreamMuted(send_ssrc));
   EXPECT_FALSE(channel->options().echo_cancellation.IsSet());
   EXPECT_EQ(0, renderer->channel_id());
+  EXPECT_TRUE(renderer->sink() != NULL);
 
+  // This will trigger SetSink(NULL) to the |renderer|.
   session_->SetAudioSend(send_ssrc, true, options, NULL);
   EXPECT_FALSE(channel->IsStreamMuted(send_ssrc));
   bool value;
   EXPECT_TRUE(channel->options().echo_cancellation.Get(&value));
   EXPECT_TRUE(value);
   EXPECT_EQ(-1, renderer->channel_id());
+  EXPECT_TRUE(renderer->sink() == NULL);
+}
+
+TEST_F(WebRtcSessionTest, AudioRendererForLocalStream) {
+  Init(NULL);
+  mediastream_signaling_.SendAudioVideoStream1();
+  CreateAndSetRemoteOfferAndLocalAnswer();
+  cricket::FakeVoiceMediaChannel* channel = media_engine_->GetVoiceChannel(0);
+  ASSERT_TRUE(channel != NULL);
+  ASSERT_EQ(1u, channel->send_streams().size());
+  uint32 send_ssrc  = channel->send_streams()[0].first_ssrc();
+
+  talk_base::scoped_ptr<FakeAudioRenderer> renderer(new FakeAudioRenderer());
+  cricket::AudioOptions options;
+  session_->SetAudioSend(send_ssrc, true, options, renderer.get());
+  EXPECT_TRUE(renderer->sink() != NULL);
+
+  // Delete the |renderer| and it will trigger OnClose() to the sink, and this
+  // will invalidate the |renderer_| pointer in the sink and prevent getting a
+  // SetSink(NULL) callback afterwards.
+  renderer.reset();
+
+  // This will trigger SetSink(NULL) if no OnClose() callback.
+  session_->SetAudioSend(send_ssrc, true, options, NULL);
 }
 
 TEST_F(WebRtcSessionTest, SetVideoPlayout) {
diff --git a/talk/base/asyncpacketsocket.h b/talk/base/asyncpacketsocket.h
index b1d5a4a..3f5fd8c 100644
--- a/talk/base/asyncpacketsocket.h
+++ b/talk/base/asyncpacketsocket.h
@@ -49,8 +49,6 @@
   std::vector<char> srtp_auth_key;  // Authentication key.
   int srtp_auth_tag_len;            // Authentication tag length.
   int64 srtp_packet_index;          // Required for Rtp Packet authentication.
-  int payload_len;                  // Raw payload length, before any wrapping
-                                    // like TURN/GTURN.
 };
 
 // This structure holds meta information for the packet which is about to send
diff --git a/talk/media/base/audiorenderer.h b/talk/media/base/audiorenderer.h
index 853813d..1553318 100644
--- a/talk/media/base/audiorenderer.h
+++ b/talk/media/base/audiorenderer.h
@@ -35,11 +35,16 @@
  public:
   class Sink {
    public:
+    // Callback to receive data from the AudioRenderer.
     virtual void OnData(const void* audio_data,
                         int bits_per_sample,
                         int sample_rate,
                         int number_of_channels,
                         int number_of_frames) = 0;
+
+    // Called when the AudioRenderer is going away.
+    virtual void OnClose() = 0;
+
    protected:
     virtual ~Sink() {}
   };
diff --git a/talk/media/base/fakemediaengine.h b/talk/media/base/fakemediaengine.h
index 86a0dbf..d2fc2ce 100644
--- a/talk/media/base/fakemediaengine.h
+++ b/talk/media/base/fakemediaengine.h
@@ -316,17 +316,18 @@
     return true;
   }
   virtual bool SetLocalRenderer(uint32 ssrc, AudioRenderer* renderer) {
-    std::map<uint32, AudioRenderer*>::iterator it = local_renderers_.find(ssrc);
+    std::map<uint32, VoiceChannelAudioSink*>::iterator it =
+        local_renderers_.find(ssrc);
     if (renderer) {
       if (it != local_renderers_.end()) {
-        ASSERT(it->second == renderer);
+        ASSERT(it->second->renderer() == renderer);
       } else {
-        local_renderers_.insert(std::make_pair(ssrc, renderer));
-        renderer->AddChannel(0);
+        local_renderers_.insert(std::make_pair(
+            ssrc, new VoiceChannelAudioSink(renderer)));
       }
     } else {
       if (it != local_renderers_.end()) {
-        it->second->RemoveChannel(0);
+        delete it->second;
         local_renderers_.erase(it);
       } else {
         return false;
@@ -419,6 +420,34 @@
     double left, right;
   };
 
+  class VoiceChannelAudioSink : public AudioRenderer::Sink {
+   public:
+    explicit VoiceChannelAudioSink(AudioRenderer* renderer)
+        : renderer_(renderer) {
+      renderer_->AddChannel(0);
+      renderer_->SetSink(this);
+    }
+    virtual ~VoiceChannelAudioSink() {
+      if (renderer_) {
+        renderer_->RemoveChannel(0);
+        renderer_->SetSink(NULL);
+      }
+    }
+    virtual void OnData(const void* audio_data,
+                        int bits_per_sample,
+                        int sample_rate,
+                        int number_of_channels,
+                        int number_of_frames) OVERRIDE {}
+    virtual void OnClose() OVERRIDE {
+      renderer_ = NULL;
+    }
+    AudioRenderer* renderer() const { return renderer_; }
+
+   private:
+    AudioRenderer* renderer_;
+  };
+
+
   FakeVoiceEngine* engine_;
   std::vector<AudioCodec> recv_codecs_;
   std::vector<AudioCodec> send_codecs_;
@@ -430,7 +459,7 @@
   bool ringback_tone_loop_;
   int time_since_last_typing_;
   AudioOptions options_;
-  std::map<uint32, AudioRenderer*> local_renderers_;
+  std::map<uint32, VoiceChannelAudioSink*> local_renderers_;
   std::map<uint32, AudioRenderer*> remote_renderers_;
 };
 
diff --git a/talk/media/base/videoadapter.cc b/talk/media/base/videoadapter.cc
index 5b53d07..dc672bb 100644
--- a/talk/media/base/videoadapter.cc
+++ b/talk/media/base/videoadapter.cc
@@ -421,7 +421,7 @@
       view_desired_interval_(0),
       encoder_desired_num_pixels_(INT_MAX),
       cpu_desired_num_pixels_(INT_MAX),
-      adapt_reason_(0),
+      adapt_reason_(ADAPTREASON_NONE),
       system_load_average_(kCpuLoadInitialAverage) {
 }
 
@@ -636,7 +636,7 @@
   }
   int old_num_pixels = GetOutputNumPixels();
   int min_num_pixels = INT_MAX;
-  adapt_reason_ = 0;
+  adapt_reason_ = ADAPTREASON_NONE;
 
   // Reduce resolution based on encoder bandwidth (GD).
   if (encoder_desired_num_pixels_ &&
@@ -677,7 +677,7 @@
         static_cast<int>(input.height * scale + .5f);
   }
   if (scale == 1.0f) {
-    adapt_reason_ = 0;
+    adapt_reason_ = ADAPTREASON_NONE;
   }
   *new_width = new_output.width = static_cast<int>(input.width * scale + .5f);
   *new_height = new_output.height = static_cast<int>(input.height * scale +
diff --git a/talk/media/base/videoadapter.h b/talk/media/base/videoadapter.h
index 6b1cdc5..70d4da7 100644
--- a/talk/media/base/videoadapter.h
+++ b/talk/media/base/videoadapter.h
@@ -111,6 +111,7 @@
  public:
   enum AdaptRequest { UPGRADE, KEEP, DOWNGRADE };
   enum AdaptReasonEnum {
+    ADAPTREASON_NONE = 0,
     ADAPTREASON_CPU = 1,
     ADAPTREASON_BANDWIDTH = 2,
     ADAPTREASON_VIEW = 4
diff --git a/talk/media/base/videocapturer.cc b/talk/media/base/videocapturer.cc
index b2f41dc..c5e725c 100644
--- a/talk/media/base/videocapturer.cc
+++ b/talk/media/base/videocapturer.cc
@@ -111,6 +111,7 @@
   screencast_max_pixels_ = 0;
   muted_ = false;
   black_frame_count_down_ = kNumBlackFramesOnMute;
+  enable_video_adapter_ = true;
 }
 
 const std::vector<VideoFormat>* VideoCapturer::GetSupportedFormats() const {
@@ -477,9 +478,9 @@
   }
 
   VideoFrame* adapted_frame = &i420_frame;
-  if (!SignalAdaptFrame.is_empty() && !IsScreencast()) {
+  if (enable_video_adapter_ && !IsScreencast()) {
     VideoFrame* out_frame = NULL;
-    SignalAdaptFrame(this, adapted_frame, &out_frame);
+    video_adapter_.AdaptFrame(adapted_frame, &out_frame);
     if (!out_frame) {
       return;  // VideoAdapter dropped the frame.
     }
diff --git a/talk/media/base/videocapturer.h b/talk/media/base/videocapturer.h
index 15c016f..37b37ba 100644
--- a/talk/media/base/videocapturer.h
+++ b/talk/media/base/videocapturer.h
@@ -37,6 +37,7 @@
 #include "talk/base/scoped_ptr.h"
 #include "talk/base/sigslot.h"
 #include "talk/base/thread.h"
+#include "talk/media/base/videoadapter.h"
 #include "talk/media/base/videocommon.h"
 #include "talk/media/devices/devicemanager.h"
 
@@ -97,12 +98,10 @@
 // capturing. The subclasses implement the video capturer for various types of
 // capturers and various platforms.
 //
-// The captured frames may need to be adapted (for example, cropping). Adaptors
-// can be registered to the capturer or applied externally to the capturer.
-// If the adaptor is needed, it acts as the downstream of VideoCapturer, adapts
-// the captured frames, and delivers the adapted frames to other components
-// such as the encoder. Effects can also be registered to the capturer or
-// applied externally.
+// The captured frames may need to be adapted (for example, cropping).
+// Video adaptation is built into and enabled by default. After a frame has
+// been captured from the device, it is sent to the video adapter, then video
+// processors, then out to the encoder.
 //
 // Programming model:
 //   Create an object of a subclass of VideoCapturer
@@ -111,6 +110,7 @@
 //   SignalFrameCaptured.connect()
 //   Find the capture format for Start() by either calling GetSupportedFormats()
 //   and selecting one of the supported or calling GetBestCaptureFormat().
+//   video_adapter()->OnOutputFormatRequest(desired_encoding_format)
 //   Start()
 //   GetCaptureFormat() optionally
 //   Stop()
@@ -255,12 +255,6 @@
   // Signal the captured frame to downstream.
   sigslot::signal2<VideoCapturer*, const CapturedFrame*,
                    sigslot::multi_threaded_local> SignalFrameCaptured;
-  // A VideoAdapter should be hooked up to SignalAdaptFrame which will be
-  // called before forwarding the frame to SignalVideoFrame. The parameters
-  // are this capturer instance, the input video frame and output frame
-  // pointer, respectively.
-  sigslot::signal3<VideoCapturer*, const VideoFrame*, VideoFrame**,
-                   sigslot::multi_threaded_local> SignalAdaptFrame;
   // Signal the captured and possibly adapted frame to downstream consumers
   // such as the encoder.
   sigslot::signal2<VideoCapturer*, const VideoFrame*,
@@ -279,6 +273,19 @@
     screencast_max_pixels_ = talk_base::_max(0, p);
   }
 
+  // If true, run video adaptation. By default, video adaptation is enabled
+  // and users must call video_adapter()->OnOutputFormatRequest()
+  // to receive frames.
+  bool enable_video_adapter() const { return enable_video_adapter_; }
+  void set_enable_video_adapter(bool enable_video_adapter) {
+    enable_video_adapter_ = enable_video_adapter;
+  }
+
+  CoordinatedVideoAdapter* video_adapter() { return &video_adapter_; }
+  const CoordinatedVideoAdapter* video_adapter() const {
+    return &video_adapter_;
+  }
+
  protected:
   // Callback attached to SignalFrameCaptured where SignalVideoFrames is called.
   void OnFrameCaptured(VideoCapturer* video_capturer,
@@ -299,6 +306,12 @@
 
   void SetCaptureFormat(const VideoFormat* format) {
     capture_format_.reset(format ? new VideoFormat(*format) : NULL);
+    if (capture_format_) {
+      ASSERT(capture_format_->interval > 0 &&
+             "Capture format expected to have positive interval.");
+      // Video adapter really only cares about capture format interval.
+      video_adapter_.SetInputFormat(*capture_format_);
+    }
   }
 
   void SetSupportedFormats(const std::vector<VideoFormat>& formats);
@@ -343,6 +356,9 @@
   bool muted_;
   int black_frame_count_down_;
 
+  bool enable_video_adapter_;
+  CoordinatedVideoAdapter video_adapter_;
+
   talk_base::CriticalSection crit_;
   VideoProcessors video_processors_;
 
diff --git a/talk/media/base/videocapturer_unittest.cc b/talk/media/base/videocapturer_unittest.cc
index 0ba932a..75da236 100644
--- a/talk/media/base/videocapturer_unittest.cc
+++ b/talk/media/base/videocapturer_unittest.cc
@@ -94,6 +94,7 @@
 };
 
 TEST_F(VideoCapturerTest, CaptureState) {
+  EXPECT_TRUE(capturer_.enable_video_adapter());
   EXPECT_EQ(cricket::CS_RUNNING, capturer_.Start(cricket::VideoFormat(
       640,
       480,
diff --git a/talk/media/base/videoengine_unittest.h b/talk/media/base/videoengine_unittest.h
index 6c782bd..2a762bc 100644
--- a/talk/media/base/videoengine_unittest.h
+++ b/talk/media/base/videoengine_unittest.h
@@ -473,6 +473,7 @@
                                 cricket::FOURCC_I420);
     EXPECT_EQ(cricket::CS_RUNNING, video_capturer_->Start(format));
     EXPECT_TRUE(channel_->SetCapturer(kSsrc, video_capturer_.get()));
+    EXPECT_TRUE(channel_->SetSendStreamFormat(kSsrc, format));
   }
   void SetUpSecondStream() {
     EXPECT_TRUE(channel_->AddRecvStream(
@@ -494,6 +495,7 @@
     EXPECT_TRUE(channel_->SetCapturer(kSsrc + 2, video_capturer_2_.get()));
     // Make the second renderer available for use by a new stream.
     EXPECT_TRUE(channel_->SetRenderer(kSsrc + 2, &renderer2_));
+    EXPECT_TRUE(channel_->SetSendStreamFormat(kSsrc + 2, format));
   }
   virtual void TearDown() {
     channel_.reset();
@@ -524,7 +526,6 @@
     if (video_capturer_) {
       EXPECT_EQ(cricket::CS_RUNNING, video_capturer_->Start(capture_format));
     }
-
     if (video_capturer_2_) {
       EXPECT_EQ(cricket::CS_RUNNING, video_capturer_2_->Start(capture_format));
     }
@@ -540,6 +541,12 @@
   bool SetSend(bool send) {
     return channel_->SetSend(send);
   }
+  bool SetSendStreamFormat(uint32 ssrc, const cricket::VideoCodec& codec) {
+    return channel_->SetSendStreamFormat(ssrc, cricket::VideoFormat(
+        codec.width, codec.height,
+        cricket::VideoFormat::FpsToInterval(codec.framerate),
+        cricket::FOURCC_ANY));
+  }
   int DrainOutgoingPackets() {
     int packets = 0;
     do {
@@ -711,6 +718,7 @@
     EXPECT_TRUE(channel_->SetCapturer(kSsrc, video_capturer_.get()));
     EXPECT_TRUE(SetOneCodec(DefaultCodec()));
     EXPECT_FALSE(channel_->sending());
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->sending());
     EXPECT_TRUE(SendFrame());
@@ -747,6 +755,7 @@
   // Tests that we can send and receive frames.
   void SendAndReceive(const cricket::VideoCodec& codec) {
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -759,6 +768,7 @@
   void SendManyResizeOnce() {
     cricket::VideoCodec codec(DefaultCodec());
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -773,6 +783,7 @@
     codec.width /= 2;
     codec.height /= 2;
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(WaitAndSendFrame(30));
     EXPECT_FRAME_WAIT(3, codec.width, codec.height, kTimeout);
     EXPECT_EQ(2, renderer_.num_set_sizes());
@@ -882,6 +893,7 @@
     EXPECT_TRUE(channel_->AddRecvStream(
         cricket::StreamParams::CreateLegacy(1234)));
     channel_->UpdateAspectRatio(640, 400);
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_TRUE(SendFrame());
@@ -902,6 +914,7 @@
     EXPECT_TRUE(channel_->AddSendStream(
         cricket::StreamParams::CreateLegacy(5678)));
     EXPECT_TRUE(channel_->SetCapturer(5678, capturer.get()));
+    EXPECT_TRUE(channel_->SetSendStreamFormat(5678, format));
     EXPECT_TRUE(channel_->AddRecvStream(
         cricket::StreamParams::CreateLegacy(5678)));
     EXPECT_TRUE(channel_->SetRenderer(5678, &renderer1));
@@ -937,6 +950,7 @@
   // Test that we can set the SSRC for the default send source.
   void SetSendSsrc() {
     EXPECT_TRUE(SetDefaultCodec());
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(SendFrame());
     EXPECT_TRUE_WAIT(NumRtpPackets() > 0, kTimeout);
@@ -958,6 +972,7 @@
     EXPECT_TRUE(channel_->AddSendStream(
         cricket::StreamParams::CreateLegacy(999)));
     EXPECT_TRUE(channel_->SetCapturer(999u, video_capturer_.get()));
+    EXPECT_TRUE(SetSendStreamFormat(999u, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(WaitAndSendFrame(0));
     EXPECT_TRUE_WAIT(NumRtpPackets() > 0, kTimeout);
@@ -982,6 +997,7 @@
     talk_base::SetBE32(packet1.data() + 8, kSsrc);
     channel_->SetRenderer(0, NULL);
     EXPECT_TRUE(SetDefaultCodec());
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -1005,6 +1021,7 @@
   // Tests setting up and configuring a send stream.
   void AddRemoveSendStreams() {
     EXPECT_TRUE(SetOneCodec(DefaultCodec()));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_TRUE(SendFrame());
@@ -1151,6 +1168,7 @@
   void AddRemoveRecvStreamAndRender() {
     cricket::FakeVideoRenderer renderer1;
     EXPECT_TRUE(SetDefaultCodec());
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_TRUE(channel_->AddRecvStream(
@@ -1195,6 +1213,7 @@
     cricket::VideoOptions vmo;
     vmo.conference_mode.Set(true);
     EXPECT_TRUE(channel_->SetOptions(vmo));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_TRUE(channel_->AddRecvStream(
@@ -1232,6 +1251,7 @@
     codec.height = 240;
     const int time_between_send = TimeBetweenSend(codec);
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -1253,6 +1273,7 @@
     int captured_frames = 1;
     for (int iterations = 0; iterations < 2; ++iterations) {
       EXPECT_TRUE(channel_->SetCapturer(kSsrc, capturer.get()));
+      EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
       talk_base::Thread::Current()->ProcessMessages(time_between_send);
       EXPECT_TRUE(capturer->CaptureCustomFrame(format.width, format.height,
                                                cricket::FOURCC_I420));
@@ -1292,6 +1313,7 @@
   // added, the plugin shouldn't crash (and no black frame should be sent).
   void RemoveCapturerWithoutAdd() {
     EXPECT_TRUE(SetOneCodec(DefaultCodec()));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -1353,6 +1375,8 @@
     // TODO(hellner): this seems like an unnecessary constraint, fix it.
     EXPECT_TRUE(channel_->SetCapturer(1, capturer1.get()));
     EXPECT_TRUE(channel_->SetCapturer(2, capturer2.get()));
+    EXPECT_TRUE(SetSendStreamFormat(1, DefaultCodec()));
+    EXPECT_TRUE(SetSendStreamFormat(2, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     // Test capturer associated with engine.
@@ -1385,6 +1409,7 @@
 
     cricket::VideoCodec codec(DefaultCodec());
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
 
     cricket::FakeVideoRenderer renderer;
@@ -1410,6 +1435,7 @@
     // Capture frame to not get same frame timestamps as previous capturer.
     capturer->CaptureFrame();
     EXPECT_TRUE(channel_->SetCapturer(kSsrc, capturer.get()));
+    EXPECT_TRUE(channel_->SetSendStreamFormat(kSsrc, capture_format));
     EXPECT_TRUE(talk_base::Thread::Current()->ProcessMessages(30));
     EXPECT_TRUE(capturer->CaptureCustomFrame(kWidth, kHeight,
                                              cricket::FOURCC_ARGB));
@@ -1429,6 +1455,7 @@
     codec.height /= 2;
     // Adapt the resolution.
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(WaitAndSendFrame(30));
     EXPECT_FRAME_WAIT(2, codec.width, codec.height, kTimeout);
   }
@@ -1442,6 +1469,7 @@
     codec.height /= 2;
     // Adapt the resolution.
     EXPECT_TRUE(SetOneCodec(codec));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, codec));
     EXPECT_TRUE(WaitAndSendFrame(30));
     EXPECT_FRAME_WAIT(2, codec.width, codec.height, kTimeout);
   }
@@ -1543,6 +1571,7 @@
   // frames being dropped.
   void SetSendStreamFormat0x0() {
     EXPECT_TRUE(SetOneCodec(DefaultCodec()));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(0, renderer_.num_rendered_frames());
@@ -1575,6 +1604,7 @@
             cricket::VideoFormat::FpsToInterval(30),
             cricket::FOURCC_I420));
     EXPECT_TRUE(channel_->SetCapturer(kSsrc, &video_capturer));
+    EXPECT_TRUE(SetSendStreamFormat(kSsrc, DefaultCodec()));
     EXPECT_TRUE(SetSend(true));
     EXPECT_TRUE(channel_->SetRender(true));
     EXPECT_EQ(frame_count, renderer_.num_rendered_frames());
diff --git a/talk/media/webrtc/webrtcvideoengine.cc b/talk/media/webrtc/webrtcvideoengine.cc
index 3e6f928..f096ac5 100644
--- a/talk/media/webrtc/webrtcvideoengine.cc
+++ b/talk/media/webrtc/webrtcvideoengine.cc
@@ -562,6 +562,8 @@
     enabled_ = enable;
   }
 
+  bool enabled() const { return enabled_; }
+
  private:
   CoordinatedVideoAdapter* video_adapter_;
   bool enabled_;
@@ -584,13 +586,8 @@
         external_capture_(external_capture),
         capturer_updated_(false),
         interval_(0),
-        cpu_monitor_(cpu_monitor) {
-    overuse_observer_.reset(new WebRtcOveruseObserver(&video_adapter_));
-    SignalCpuAdaptationUnable.repeat(video_adapter_.SignalCpuAdaptationUnable);
-    if (cpu_monitor) {
-      cpu_monitor->SignalUpdate.connect(
-          &video_adapter_, &CoordinatedVideoAdapter::OnCpuLoadUpdated);
-    }
+        cpu_monitor_(cpu_monitor),
+        overuse_observer_enabled_(false) {
   }
 
   int channel_id() const { return channel_id_; }
@@ -614,7 +611,10 @@
     if (video_format_ != cricket::VideoFormat()) {
       interval_ = video_format_.interval;
     }
-    video_adapter_.OnOutputFormatRequest(video_format_);
+    CoordinatedVideoAdapter* adapter = video_adapter();
+    if (adapter) {
+      adapter->OnOutputFormatRequest(video_format_);
+    }
   }
   void set_interval(int64 interval) {
     if (video_format() == cricket::VideoFormat()) {
@@ -623,17 +623,12 @@
   }
   int64 interval() { return interval_; }
 
-  void InitializeAdapterOutputFormat(const webrtc::VideoCodec& codec) {
-    VideoFormat format(codec.width, codec.height,
-                       VideoFormat::FpsToInterval(codec.maxFramerate),
-                       FOURCC_I420);
-    if (video_adapter_.output_format().IsSize0x0()) {
-      video_adapter_.SetOutputFormat(format);
-    }
-  }
-
   int CurrentAdaptReason() const {
-    return video_adapter_.adapt_reason();
+    const CoordinatedVideoAdapter* adapter = video_adapter();
+    if (!adapter) {
+      return CoordinatedVideoAdapter::ADAPTREASON_NONE;
+    }
+    return video_adapter()->adapt_reason();
   }
   webrtc::CpuOveruseObserver* overuse_observer() {
     return overuse_observer_.get();
@@ -658,69 +653,113 @@
     if (video_capturer == video_capturer_) {
       return;
     }
-    capturer_updated_ = true;
 
-    // Disconnect from the previous video capturer.
-    if (video_capturer_) {
-      video_capturer_->SignalAdaptFrame.disconnect(this);
-    }
-
-    video_capturer_ = video_capturer;
-    if (video_capturer && !video_capturer->IsScreencast()) {
-      const VideoFormat* capture_format = video_capturer->GetCaptureFormat();
-      if (capture_format) {
-        // TODO(thorcarpenter): This is broken. Video capturer doesn't have
-        // a capture format until the capturer is started. So, if
-        // the capturer is started immediately after calling set_video_capturer
-        // video adapter may not have the input format set, the interval may
-        // be zero, and all frames may be dropped.
-        // Consider fixing this by having video_adapter keep a pointer to the
-        // video capturer.
-        video_adapter_.SetInputFormat(*capture_format);
+    CoordinatedVideoAdapter* old_video_adapter = video_adapter();
+    if (old_video_adapter) {
+      // Disconnect signals from old video adapter.
+      SignalCpuAdaptationUnable.disconnect(old_video_adapter);
+      if (cpu_monitor_) {
+        cpu_monitor_->SignalUpdate.disconnect(old_video_adapter);
       }
-      // TODO(thorcarpenter): When the adapter supports "only frame dropping"
-      // mode, also hook it up to screencast capturers.
-      video_capturer->SignalAdaptFrame.connect(
-          this, &WebRtcVideoChannelSendInfo::AdaptFrame);
     }
+
+    capturer_updated_ = true;
+    video_capturer_ = video_capturer;
+
+    if (!video_capturer) {
+      overuse_observer_.reset();
+      return;
+    }
+
+    CoordinatedVideoAdapter* adapter = video_adapter();
+    ASSERT(adapter && "Video adapter should not be null here.");
+
+    UpdateAdapterCpuOptions();
+    adapter->OnOutputFormatRequest(video_format_);
+
+    overuse_observer_.reset(new WebRtcOveruseObserver(adapter));
+    // (Dis)connect the video adapter from the cpu monitor as appropriate.
+    SetCpuOveruseDetection(overuse_observer_enabled_);
+
+    SignalCpuAdaptationUnable.repeat(adapter->SignalCpuAdaptationUnable);
   }
 
-  CoordinatedVideoAdapter* video_adapter() { return &video_adapter_; }
-
-  void AdaptFrame(VideoCapturer* capturer, const VideoFrame* input,
-                  VideoFrame** adapted) {
-    video_adapter_.AdaptFrame(input, adapted);
+  CoordinatedVideoAdapter* video_adapter() {
+    if (!video_capturer_) {
+      return NULL;
+    }
+    return video_capturer_->video_adapter();
+  }
+  const CoordinatedVideoAdapter* video_adapter() const {
+    if (!video_capturer_) {
+      return NULL;
+    }
+    return video_capturer_->video_adapter();
   }
 
-  void ApplyCpuOptions(const VideoOptions& options) {
+  void ApplyCpuOptions(const VideoOptions& video_options) {
+    // Use video_options_.SetAll() instead of assignment so that unset value in
+    // video_options will not overwrite the previous option value.
+    video_options_.SetAll(video_options);
+    UpdateAdapterCpuOptions();
+  }
+
+  void UpdateAdapterCpuOptions() {
+    if (!video_capturer_) {
+      return;
+    }
+
     bool cpu_adapt, cpu_smoothing, adapt_third;
     float low, med, high;
-    if (options.adapt_input_to_cpu_usage.Get(&cpu_adapt)) {
-      video_adapter_.set_cpu_adaptation(cpu_adapt);
+
+    // TODO(thorcarpenter): Have VideoAdapter be responsible for setting
+    // all these video options.
+    CoordinatedVideoAdapter* video_adapter = video_capturer_->video_adapter();
+    if (video_options_.adapt_input_to_cpu_usage.Get(&cpu_adapt)) {
+      video_adapter->set_cpu_adaptation(cpu_adapt);
     }
-    if (options.adapt_cpu_with_smoothing.Get(&cpu_smoothing)) {
-      video_adapter_.set_cpu_smoothing(cpu_smoothing);
+    if (video_options_.adapt_cpu_with_smoothing.Get(&cpu_smoothing)) {
+      video_adapter->set_cpu_smoothing(cpu_smoothing);
     }
-    if (options.process_adaptation_threshhold.Get(&med)) {
-      video_adapter_.set_process_threshold(med);
+    if (video_options_.process_adaptation_threshhold.Get(&med)) {
+      video_adapter->set_process_threshold(med);
     }
-    if (options.system_low_adaptation_threshhold.Get(&low)) {
-      video_adapter_.set_low_system_threshold(low);
+    if (video_options_.system_low_adaptation_threshhold.Get(&low)) {
+      video_adapter->set_low_system_threshold(low);
     }
-    if (options.system_high_adaptation_threshhold.Get(&high)) {
-      video_adapter_.set_high_system_threshold(high);
+    if (video_options_.system_high_adaptation_threshhold.Get(&high)) {
+      video_adapter->set_high_system_threshold(high);
     }
-    if (options.video_adapt_third.Get(&adapt_third)) {
-      video_adapter_.set_scale_third(adapt_third);
+    if (video_options_.video_adapt_third.Get(&adapt_third)) {
+      video_adapter->set_scale_third(adapt_third);
     }
   }
 
   void SetCpuOveruseDetection(bool enable) {
-    if (cpu_monitor_ && enable) {
-      cpu_monitor_->SignalUpdate.disconnect(&video_adapter_);
+    overuse_observer_enabled_ = enable;
+
+    if (!overuse_observer_) {
+      // Cannot actually use the overuse detector until it is initialized
+      // with a video adapter.
+      return;
     }
     overuse_observer_->Enable(enable);
-    video_adapter_.set_cpu_adaptation(enable);
+
+    // If overuse detection is enabled, it will signal the video adapter
+    // instead of the cpu monitor. If disabled, connect the adapter to the
+    // cpu monitor.
+    CoordinatedVideoAdapter* adapter = video_adapter();
+    if (adapter) {
+      adapter->set_cpu_adaptation(enable);
+      if (cpu_monitor_) {
+        if (enable) {
+          cpu_monitor_->SignalUpdate.disconnect(adapter);
+        } else {
+          cpu_monitor_->SignalUpdate.connect(
+              adapter, &CoordinatedVideoAdapter::OnCpuLoadUpdated);
+        }
+      }
+    }
   }
 
   void ProcessFrame(const VideoFrame& original_frame, bool mute,
@@ -774,9 +813,11 @@
 
   int64 interval_;
 
-  CoordinatedVideoAdapter video_adapter_;
   talk_base::CpuMonitor* cpu_monitor_;
   talk_base::scoped_ptr<WebRtcOveruseObserver> overuse_observer_;
+  bool overuse_observer_enabled_;
+
+  VideoOptions video_options_;
 };
 
 const WebRtcVideoEngine::VideoCodecPref
@@ -1677,12 +1718,6 @@
     return false;
   }
 
-  for (SendChannelMap::iterator iter = send_channels_.begin();
-       iter != send_channels_.end(); ++iter) {
-    WebRtcVideoChannelSendInfo* send_channel = iter->second;
-    send_channel->InitializeAdapterOutputFormat(codec);
-  }
-
   LogSendCodecChange("SetSendCodecs()");
 
   return true;
@@ -1698,10 +1733,6 @@
 
 bool WebRtcVideoMediaChannel::SetSendStreamFormat(uint32 ssrc,
                                                   const VideoFormat& format) {
-  if (!send_codec_) {
-    LOG(LS_ERROR) << "The send codec has not been set yet.";
-    return false;
-  }
   WebRtcVideoChannelSendInfo* send_channel = GetSendChannel(ssrc);
   if (!send_channel) {
     LOG(LS_ERROR) << "The specified ssrc " << ssrc << " is not in use.";
diff --git a/talk/media/webrtc/webrtcvideoengine_unittest.cc b/talk/media/webrtc/webrtcvideoengine_unittest.cc
index f5622ef..73e3c77 100644
--- a/talk/media/webrtc/webrtcvideoengine_unittest.cc
+++ b/talk/media/webrtc/webrtcvideoengine_unittest.cc
@@ -1292,6 +1292,7 @@
         cricket::StreamParams::CreateLegacy(kSsrcs2[i])));
     // Register the capturer to the ssrc.
     EXPECT_TRUE(channel_->SetCapturer(kSsrcs2[i], &capturer));
+    EXPECT_TRUE(channel_->SetSendStreamFormat(kSsrcs2[i], capture_format_vga));
   }
 
   const int channel0 = vie_.GetChannelFromLocalSsrc(kSsrcs2[0]);
diff --git a/talk/media/webrtc/webrtcvoiceengine.cc b/talk/media/webrtc/webrtcvoiceengine.cc
index e2415cf..8db8c99 100644
--- a/talk/media/webrtc/webrtcvoiceengine.cc
+++ b/talk/media/webrtc/webrtcvoiceengine.cc
@@ -1675,10 +1675,12 @@
 
   // Starts the rendering by setting a sink to the renderer to get data
   // callback.
+  // This method is called on the libjingle worker thread.
   // TODO(xians): Make sure Start() is called only once.
   void Start(AudioRenderer* renderer) {
+    talk_base::CritScope lock(&lock_);
     ASSERT(renderer != NULL);
-    if (renderer_) {
+    if (renderer_ != NULL) {
       ASSERT(renderer_ == renderer);
       return;
     }
@@ -1692,8 +1694,10 @@
 
   // Stops rendering by setting the sink of the renderer to NULL. No data
   // callback will be received after this method.
+  // This method is called on the libjingle worker thread.
   void Stop() {
-    if (!renderer_)
+    talk_base::CritScope lock(&lock_);
+    if (renderer_ == NULL)
       return;
 
     renderer_->RemoveChannel(channel_);
@@ -1702,13 +1706,29 @@
   }
 
   // AudioRenderer::Sink implementation.
+  // This method is called on the audio thread.
   virtual void OnData(const void* audio_data,
                       int bits_per_sample,
                       int sample_rate,
                       int number_of_channels,
                       int number_of_frames) OVERRIDE {
-    // TODO(xians): Make new interface in AudioTransport to pass the data to
-    // WebRtc VoE channel.
+#ifdef USE_WEBRTC_DEV_BRANCH
+    voe_audio_transport_->OnData(channel_,
+                                 audio_data,
+                                 bits_per_sample,
+                                 sample_rate,
+                                 number_of_channels,
+                                 number_of_frames);
+#endif
+  }
+
+  // Callback from the |renderer_| when it is going away. In case Start() has
+  // never been called, this callback won't be triggered.
+  virtual void OnClose() OVERRIDE {
+    talk_base::CritScope lock(&lock_);
+    // Set |renderer_| to NULL to make sure no more callback will get into
+    // the renderer.
+    renderer_ = NULL;
   }
 
   // Accessor to the VoE channel ID.
@@ -1722,6 +1742,9 @@
   // PeerConnection will make sure invalidating the pointer before the object
   // goes away.
   AudioRenderer* renderer_;
+
+  // Protects |renderer_| in Start(), Stop() and OnClose().
+  talk_base::CriticalSection lock_;
 };
 
 // WebRtcVoiceMediaChannel
diff --git a/talk/session/media/externalhmac.cc b/talk/session/media/externalhmac.cc
new file mode 100644
index 0000000..d5cfc95
--- /dev/null
+++ b/talk/session/media/externalhmac.cc
@@ -0,0 +1,186 @@
+/*
+ * libjingle
+ * Copyright 2014 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
+
+#ifdef SRTP_RELATIVE_PATH
+#include "srtp.h"  // NOLINT
+#else
+#include "third_party/libsrtp/include/srtp.h"
+#endif  // SRTP_RELATIVE_PATH
+
+#include "talk/session/media/external_hmac.h"
+
+#include "talk/base/logging.h"
+
+// The debug module for authentiation
+debug_module_t mod_external_hmac = {
+  0,                            // Debugging is off by default
+  (char*)"external-hmac-sha-1"  // Printable name for module
+};
+
+extern auth_type_t external_hmac;
+
+// Begin test case 0 */
+uint8_t
+external_hmac_test_case_0_key[20] = {
+  0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+  0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
+  0x0b, 0x0b, 0x0b, 0x0b
+};
+
+uint8_t
+external_hmac_test_case_0_data[8] = {
+  0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65   // "Hi There"
+};
+
+uint8_t
+external_hmac_fake_tag[10] = {
+  0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd
+};
+
+auth_test_case_t
+external_hmac_test_case_0 = {
+  20,                                // Octets in key
+  external_hmac_test_case_0_key,     // Key
+  8,                                 // Octets in data
+  external_hmac_test_case_0_data,    // Data
+  10,                                // Octets in tag
+  external_hmac_fake_tag,            // Tag
+  NULL                               // Pointer to next testcase
+};
+
+err_status_t
+external_hmac_alloc(auth_t** a, int key_len, int out_len) {
+  uint8_t* pointer;
+
+  // Check key length - note that we don't support keys larger
+  // than 20 bytes yet
+  if (key_len > 20)
+    return err_status_bad_param;
+
+  // Check output length - should be less than 20 bytes/
+  if (out_len > 20)
+    return err_status_bad_param;
+
+  // Allocate memory for auth and hmac_ctx_t structures.
+  pointer = reinterpret_cast<uint8_t*>(
+      crypto_alloc(sizeof(external_hmac_ctx_t) + sizeof(auth_t)));
+  if (pointer == NULL)
+    return err_status_alloc_fail;
+
+  // Set pointers
+  *a = (auth_t *)pointer;
+  (*a)->type = &external_hmac;
+  (*a)->state = pointer + sizeof(auth_t);
+  (*a)->out_len = out_len;
+  (*a)->key_len = key_len;
+  (*a)->prefix_len = 0;
+
+  // Increment global count of all hmac uses.
+  external_hmac.ref_count++;
+
+  return err_status_ok;
+}
+
+err_status_t
+external_hmac_dealloc(auth_t* a) {
+  // Zeroize entire state
+  octet_string_set_to_zero((uint8_t *)a,
+         sizeof(external_hmac_ctx_t) + sizeof(auth_t));
+
+  // Free memory
+  crypto_free(a);
+
+  // Decrement global count of all hmac uses.
+  external_hmac.ref_count--;
+
+  return err_status_ok;
+}
+
+err_status_t
+external_hmac_init(external_hmac_ctx_t* state,
+                   const uint8_t* key, int key_len) {
+  if (key_len > HMAC_KEY_LENGTH)
+    return err_status_bad_param;
+
+  memset(state->key, 0, key_len);
+  memcpy(state->key, key, key_len);
+  state->key_length = key_len;
+  return err_status_ok;
+}
+
+err_status_t
+external_hmac_start(external_hmac_ctx_t* state) {
+  return err_status_ok;
+}
+
+err_status_t
+external_hmac_update(external_hmac_ctx_t* state, const uint8_t* message,
+                     int msg_octets) {
+  return err_status_ok;
+}
+
+err_status_t
+external_hmac_compute(external_hmac_ctx_t* state, const void* message,
+                      int msg_octets, int tag_len, uint8_t* result) {
+  memcpy(result, external_hmac_fake_tag, tag_len);
+  return err_status_ok;
+}
+
+char external_hmac_description[] = "external hmac sha-1 authentication";
+
+ // auth_type_t external_hmac is the hmac metaobject
+
+auth_type_t
+external_hmac  = {
+  (auth_alloc_func)      external_hmac_alloc,
+  (auth_dealloc_func)    external_hmac_dealloc,
+  (auth_init_func)       external_hmac_init,
+  (auth_compute_func)    external_hmac_compute,
+  (auth_update_func)     external_hmac_update,
+  (auth_start_func)      external_hmac_start,
+  (char *)               external_hmac_description,
+  (int)                  0,  /* instance count */
+  (auth_test_case_t *)   &external_hmac_test_case_0,
+  (debug_module_t *)     &mod_external_hmac,
+  (auth_type_id_t)       EXTERNAL_HMAC_SHA1
+};
+
+err_status_t
+external_crypto_init() {
+  err_status_t status = crypto_kernel_replace_auth_type(
+      &external_hmac, EXTERNAL_HMAC_SHA1);
+  if (status) {
+    LOG(LS_ERROR) << "Error in replacing default auth module, error: "
+                  << status;
+    return err_status_fail;
+  }
+  return err_status_ok;
+}
+
+#endif  // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
diff --git a/talk/session/media/externalhmac.h b/talk/session/media/externalhmac.h
new file mode 100644
index 0000000..47a195f
--- /dev/null
+++ b/talk/session/media/externalhmac.h
@@ -0,0 +1,91 @@
+/*
+ * libjingle
+ * Copyright 2014 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_
+#define TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_
+
+// External libsrtp HMAC auth module which implements methods defined in
+// auth_type_t.
+// The default auth module will be replaced only when the ENABLE_EXTERNAL_AUTH
+// flag is enabled. This allows us to access to authentication keys,
+// as the default auth implementation doesn't provide access and avoids
+// hashing each packet twice.
+
+// How will libsrtp select this module?
+// Libsrtp defines authentication function types identified by an unsigned
+// integer, e.g. HMAC_SHA1 is 3. Using authentication ids, the application
+// can plug any desired authentication modules into libsrtp.
+// libsrtp also provides a mechanism to select different auth functions for
+// individual streams. This can be done by setting the right value in
+// the auth_type of srtp_policy_t. The application must first register auth
+// functions and the corresponding authentication id using
+// crypto_kernel_replace_auth_type function.
+#if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
+
+#ifdef SRTP_RELATIVE_PATH
+#include "crypto_types.h"  // NOLINT
+#else
+#include "third_party/libsrtp/crypto/include/crypto_types.h"
+#endif  // SRTP_RELATIVE_PATH
+
+#define EXTERNAL_HMAC_SHA1 HMAC_SHA1 + 1
+#define HMAC_KEY_LENGTH 20
+
+// The HMAC context structure used to store authentication keys.
+// The pointer to the key  will be allocated in the external_hmac_init function.
+// This pointer is owned by srtp_t in a template context.
+typedef struct {
+  uint8_t key[HMAC_KEY_LENGTH];
+  int key_length;
+} external_hmac_ctx_t;
+
+err_status_t
+external_hmac_alloc(auth_t** a, int key_len, int out_len);
+
+err_status_t
+external_hmac_dealloc(auth_t* a);
+
+err_status_t
+external_hmac_init(external_hmac_ctx_t* state,
+                   const uint8_t* key, int key_len);
+
+err_status_t
+external_hmac_start(external_hmac_ctx_t* state);
+
+err_status_t
+external_hmac_update(external_hmac_ctx_t* state, const uint8_t* message,
+                     int msg_octets);
+
+err_status_t
+external_hmac_compute(external_hmac_ctx_t* state, const void* message,
+                      int msg_octets, int tag_len, uint8_t* result);
+
+err_status_t
+external_crypto_init();
+
+#endif  // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
+#endif  // TALK_SESSION_MEDIA_EXTERNAL_HMAC_H_
diff --git a/talk/session/media/srtpfilter.cc b/talk/session/media/srtpfilter.cc
index 8e1c2c1..2f14268 100644
--- a/talk/session/media/srtpfilter.cc
+++ b/talk/session/media/srtpfilter.cc
@@ -44,9 +44,16 @@
 #ifdef HAVE_SRTP
 #ifdef SRTP_RELATIVE_PATH
 #include "srtp.h"  // NOLINT
+extern "C" srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
+#include "srtp_priv.h"  // NOLINT
 #else
 #include "third_party/libsrtp/include/srtp.h"
+extern "C" srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
+#include "third_party/libsrtp/include/srtp_priv.h"
 #endif  // SRTP_RELATIVE_PATH
+#ifdef  ENABLE_EXTERNAL_AUTH
+#include "talk/session/media/external_hmac.h"
+#endif  // ENABLE_EXTERNAL_AUTH
 #ifdef _DEBUG
 extern "C" debug_module_t mod_srtp;
 extern "C" debug_module_t mod_auth;
@@ -158,7 +165,6 @@
   LOG(LS_INFO) << "SRTP activated with negotiated parameters:"
                << " send cipher_suite " << send_cs
                << " recv cipher_suite " << recv_cs;
-
   return true;
 }
 
@@ -208,6 +214,16 @@
   return send_session_->ProtectRtp(p, in_len, max_len, out_len);
 }
 
+bool SrtpFilter::ProtectRtp(void* p, int in_len, int max_len, int* out_len,
+                            int64* index) {
+  if (!IsActive()) {
+    LOG(LS_WARNING) << "Failed to ProtectRtp: SRTP not active";
+    return false;
+  }
+
+  return send_session_->ProtectRtp(p, in_len, max_len, out_len, index);
+}
+
 bool SrtpFilter::ProtectRtcp(void* p, int in_len, int max_len, int* out_len) {
   if (!IsActive()) {
     LOG(LS_WARNING) << "Failed to ProtectRtcp: SRTP not active";
@@ -240,6 +256,15 @@
   }
 }
 
+bool SrtpFilter::GetRtpAuthParams(uint8** key, int* key_len, int* tag_len) {
+  if (!IsActive()) {
+    LOG(LS_WARNING) << "Failed to GetRtpAuthParams: SRTP not active";
+    return false;
+  }
+
+  return send_session_->GetRtpAuthParams(key, key_len, tag_len);
+}
+
 void SrtpFilter::set_signal_silent_time(uint32 signal_silent_time_in_ms) {
   signal_silent_time_in_ms_ = signal_silent_time_in_ms;
   if (state_ == ST_ACTIVE) {
@@ -496,6 +521,14 @@
   return true;
 }
 
+bool SrtpSession::ProtectRtp(void* p, int in_len, int max_len, int* out_len,
+                             int64* index) {
+  if (!ProtectRtp(p, in_len, max_len, out_len)) {
+    return false;
+  }
+  return (index) ? GetSendStreamPacketIndex(p, in_len, index) : true;
+}
+
 bool SrtpSession::ProtectRtcp(void* p, int in_len, int max_len, int* out_len) {
   if (!session_) {
     LOG(LS_WARNING) << "Failed to protect SRTCP packet: no SRTP Session";
@@ -554,6 +587,42 @@
   return true;
 }
 
+bool SrtpSession::GetRtpAuthParams(uint8** key, int* key_len,
+                                   int* tag_len) {
+#if defined(ENABLE_EXTERNAL_AUTH)
+  external_hmac_ctx_t* external_hmac = NULL;
+  // stream_template will be the reference context for other streams.
+  // Let's use it for getting the keys.
+  srtp_stream_ctx_t* srtp_context = session_->stream_template;
+  if (srtp_context && srtp_context->rtp_auth) {
+    external_hmac = reinterpret_cast<external_hmac_ctx_t*>(
+        srtp_context->rtp_auth->state);
+  }
+
+  if (!external_hmac) {
+    LOG(LS_ERROR) << "Failed to get auth keys from libsrtp!.";
+    return false;
+  }
+
+  *key = external_hmac->key;
+  *key_len = external_hmac->key_length;
+  *tag_len = rtp_auth_tag_len_;
+  return true;
+#else
+  return false;
+#endif
+}
+
+bool SrtpSession::GetSendStreamPacketIndex(void* p, int in_len, int64* index) {
+  srtp_hdr_t* hdr = reinterpret_cast<srtp_hdr_t*>(p);
+  srtp_stream_ctx_t* stream = srtp_get_stream(session_, hdr->ssrc);
+  if (stream == NULL)
+    return false;
+
+  *index = rdbx_get_packet_index(&stream->rtp_rdbx);
+  return true;
+}
+
 void SrtpSession::set_signal_silent_time(uint32 signal_silent_time_in_ms) {
   srtp_stat_->set_signal_silent_time(signal_silent_time_in_ms);
 }
@@ -596,6 +665,13 @@
   // TODO(astor) parse window size from WSH session-param
   policy.window_size = 1024;
   policy.allow_repeat_tx = 1;
+  // If external authentication option is enabled, supply custom auth module
+  // id EXTERNAL_HMAC_SHA1 in the policy structure.
+  // We want to set this option only for rtp packets.
+  // By default policy structure is initialized to HMAC_SHA1.
+#if defined(ENABLE_EXTERNAL_AUTH)
+  policy.rtp.auth_type = EXTERNAL_HMAC_SHA1;
+#endif
   policy.next = NULL;
 
   int err = srtp_create(&session_, &policy);
@@ -604,6 +680,7 @@
     return false;
   }
 
+
   rtp_auth_tag_len_ = policy.rtp.auth_tag_len;
   rtcp_auth_tag_len_ = policy.rtcp.auth_tag_len;
   return true;
@@ -623,7 +700,13 @@
       LOG(LS_ERROR) << "Failed to install SRTP event handler, err=" << err;
       return false;
     }
-
+#if defined(ENABLE_EXTERNAL_AUTH)
+    err = external_crypto_init();
+    if (err != err_status_ok) {
+      LOG(LS_ERROR) << "Failed to initialize fake auth, err=" << err;
+      return false;
+    }
+#endif
     inited_ = true;
   }
 
diff --git a/talk/session/media/srtpfilter.h b/talk/session/media/srtpfilter.h
index b6a2699..bc1735a 100644
--- a/talk/session/media/srtpfilter.h
+++ b/talk/session/media/srtpfilter.h
@@ -122,12 +122,18 @@
   // Encrypts/signs an individual RTP/RTCP packet, in-place.
   // If an HMAC is used, this will increase the packet size.
   bool ProtectRtp(void* data, int in_len, int max_len, int* out_len);
+  // Overloaded version, outputs packet index.
+  bool ProtectRtp(void* data, int in_len, int max_len, int* out_len,
+                  int64* index);
   bool ProtectRtcp(void* data, int in_len, int max_len, int* out_len);
   // Decrypts/verifies an invidiual RTP/RTCP packet.
   // If an HMAC is used, this will decrease the packet size.
   bool UnprotectRtp(void* data, int in_len, int* out_len);
   bool UnprotectRtcp(void* data, int in_len, int* out_len);
 
+  // Returns rtp auth params from srtp context.
+  bool GetRtpAuthParams(uint8** key, int* key_len, int* tag_len);
+
   // Update the silent threshold (in ms) for signaling errors.
   void set_signal_silent_time(uint32 signal_silent_time_in_ms);
 
@@ -200,12 +206,18 @@
   // Encrypts/signs an individual RTP/RTCP packet, in-place.
   // If an HMAC is used, this will increase the packet size.
   bool ProtectRtp(void* data, int in_len, int max_len, int* out_len);
+  // Overloaded version, outputs packet index.
+  bool ProtectRtp(void* data, int in_len, int max_len, int* out_len,
+                  int64* index);
   bool ProtectRtcp(void* data, int in_len, int max_len, int* out_len);
   // Decrypts/verifies an invidiual RTP/RTCP packet.
   // If an HMAC is used, this will decrease the packet size.
   bool UnprotectRtp(void* data, int in_len, int* out_len);
   bool UnprotectRtcp(void* data, int in_len, int* out_len);
 
+  // Helper method to get authentication params.
+  bool GetRtpAuthParams(uint8** key, int* key_len, int* tag_len);
+
   // Update the silent threshold (in ms) for signaling errors.
   void set_signal_silent_time(uint32 signal_silent_time_in_ms);
 
@@ -217,9 +229,13 @@
 
  private:
   bool SetKey(int type, const std::string& cs, const uint8* key, int len);
+    // Returns send stream current packet index from srtp db.
+  bool GetSendStreamPacketIndex(void* data, int in_len, int64* index);
+
   static bool Init();
   void HandleEvent(const srtp_event_data_t* ev);
   static void HandleEventThunk(srtp_event_data_t* ev);
+
   static std::list<SrtpSession*>* sessions();
 
   srtp_t session_;
diff --git a/talk/session/media/srtpfilter_unittest.cc b/talk/session/media/srtpfilter_unittest.cc
index 1b4aef2..680b9d6 100644
--- a/talk/session/media/srtpfilter_unittest.cc
+++ b/talk/session/media/srtpfilter_unittest.cc
@@ -522,6 +522,25 @@
                                  kTestKey1, kTestKeyLen - 1));
 }
 
+#if defined(ENABLE_EXTERNAL_AUTH)
+TEST_F(SrtpFilterTest, TestGetSendAuthParams) {
+  EXPECT_TRUE(f1_.SetRtpParams(CS_AES_CM_128_HMAC_SHA1_32,
+                               kTestKey1, kTestKeyLen,
+                               CS_AES_CM_128_HMAC_SHA1_32,
+                               kTestKey2, kTestKeyLen));
+  EXPECT_TRUE(f1_.SetRtcpParams(CS_AES_CM_128_HMAC_SHA1_32,
+                                kTestKey1, kTestKeyLen,
+                                CS_AES_CM_128_HMAC_SHA1_32,
+                                kTestKey2, kTestKeyLen));
+  uint8* auth_key = NULL;
+  int auth_key_len = 0, auth_tag_len = 0;
+  EXPECT_TRUE(f1_.GetRtpAuthParams(&auth_key, &auth_key_len, &auth_tag_len));
+  EXPECT_TRUE(auth_key != NULL);
+  EXPECT_EQ(20, auth_key_len);
+  EXPECT_EQ(4, auth_tag_len);
+}
+#endif
+
 class SrtpSessionTest : public testing::Test {
  protected:
   virtual void SetUp() {
@@ -606,6 +625,15 @@
   TestUnprotectRtcp(CS_AES_CM_128_HMAC_SHA1_32);
 }
 
+TEST_F(SrtpSessionTest, TestGetSendStreamPacketIndex) {
+  EXPECT_TRUE(s1_.SetSend(CS_AES_CM_128_HMAC_SHA1_32, kTestKey1, kTestKeyLen));
+  int64 index;
+  int out_len = 0;
+  EXPECT_TRUE(s1_.ProtectRtp(rtp_packet_, rtp_len_,
+                             sizeof(rtp_packet_), &out_len, &index));
+  EXPECT_EQ(1, index);
+}
+
 // Test that we fail to unprotect if someone tampers with the RTP/RTCP paylaods.
 TEST_F(SrtpSessionTest, TestTamperReject) {
   int out_len;