WebRtc-PeerConnectionObserver

主要实现函数

//信令状态改变  
void OnSignalingChange(
      webrtc::PeerConnectionInterface::SignalingState new_state) override {}
//添加轨道（音频，视频）
  void OnAddTrack(
      rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
      const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface>>&
          streams) override;
//移除轨道，需要在UI线程或者主线程中调用Release()进行释放
  void OnRemoveTrack(
      rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver) override;
//数据轨道
  void OnDataChannel(
      rtc::scoped_refptr<webrtc::DataChannelInterface> channel) override {}
  void OnRenegotiationNeeded() override {}
  void OnIceConnectionChange(
      webrtc::PeerConnectionInterface::IceConnectionState new_state) override {}
  void OnIceGatheringChange(
      webrtc::PeerConnectionInterface::IceGatheringState new_state) override {}
  void OnIceCandidate(const webrtc::IceCandidateInterface* candidate) override;
  void OnIceConnectionReceivingChange(bool receiving) override {}

void Conductor::OnAddTrack(
    rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
    const std::vector<rtc::scoped_refptr<webrtc::MediaStreamInterface>>&
        streams) {
  RTC_LOG(INFO) << __FUNCTION__ << " " << receiver->id();
  main_wnd_->QueueUIThreadCallback(NEW_TRACK_ADDED,
                                   receiver->track().release());
}

void Conductor::OnRemoveTrack(
    rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver) {
  RTC_LOG(INFO) << __FUNCTION__ << " " << receiver->id();
  main_wnd_->QueueUIThreadCallback(TRACK_REMOVED, receiver->track().release());
}

void Conductor::OnIceCandidate(const webrtc::IceCandidateInterface* candidate) {
  RTC_LOG(INFO) << __FUNCTION__ << " " << candidate->sdp_mline_index();
  // For loopback test. To save some connecting delay.
  if (loopback_) {
    if (!peer_connection_->AddIceCandidate(candidate)) {
      RTC_LOG(WARNING) << "Failed to apply the received candidate";
    }
    return;
  }

  Json::StyledWriter writer;
  Json::Value jmessage;

  jmessage[kCandidateSdpMidName] = candidate->sdp_mid();
  jmessage[kCandidateSdpMlineIndexName] = candidate->sdp_mline_index();
  std::string sdp;
  if (!candidate->ToString(&sdp)) {
    RTC_LOG(LS_ERROR) << "Failed to serialize candidate";
    return;
  }
  jmessage[kCandidateSdpName] = sdp;
  SendMessage(writer.write(jmessage));
}