Reset the BWE when the network changes

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 3fd7a931d0cecc88cff0b30a47557db5a21ed586..5fb54875c5901a9a6be69a0a4ef9af1c5150ea2b 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -88,6 +88,8 @@ class Call : public webrtc::Call, public PacketReceiver,
       const webrtc::Call::Config::BitrateConfig& bitrate_config) override;
   void SignalNetworkState(NetworkState state) override;
 
+  void OnNetworkChanged(int local_net_id, int remote_net_id) override;
+
   void OnSentPacket(const rtc::SentPacket& sent_packet) override;
 
   // Implements BitrateObserver.
@@ -101,7 +103,7 @@ class Call : public webrtc::Call, public PacketReceiver,
                             const uint8_t* packet,
                             size_t length,
                             const PacketTime& packet_time);
-
+  void ResetBweBitrates();
   void ConfigureSync(const std::string& sync_group)
       EXCLUSIVE_LOCKS_REQUIRED(receive_crit_);
 
@@ -167,6 +169,9 @@ class Call : public webrtc::Call, public PacketReceiver,
   int64_t pacer_bitrate_sum_kbits_ GUARDED_BY(&bitrate_crit_);
   int64_t num_bitrate_updates_ GUARDED_BY(&bitrate_crit_);
 
+  int local_network_id_ = 0;
+  int remote_network_id_ = 0;

[pthatcher1, 2016/03/16 21:22:03]

If the signal has both old and new route infos, we don't have to store these.

[honghaiz3, 2016/03/17 03:38:27]

Keep this as we have discussed.

+
   VieRemb remb_;
   const std::unique_ptr<CongestionController> congestion_controller_;
 
@@ -570,6 +575,30 @@ void Call::SignalNetworkState(NetworkState state) {
   }
 }
 
+void Call::OnNetworkChanged(int local_net_id, int remote_net_id) {
+  RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
+  // Reset the BWE estimate when network changes.
+  // Check if the network has actually changed.
+  if (local_net_id == local_network_id_ &&
+      remote_net_id == remote_network_id_) {

[pthatcher1, 2016/03/16 21:22:03]

If we use NetworkRoute structs, we should also check if they are connected or
not.

[honghaiz3, 2016/03/17 03:38:27]

We can now use the null pointer for best connection being deleted.

+    return;
+  }
+  LOG(LS_INFO) << "Network changed: new local network id " << local_net_id
+               << " new remote network id " << remote_net_id;
+  local_network_id_ = local_net_id;
+  remote_network_id_ = remote_net_id;
+  ResetBweBitrates();
+}
+
+void Call::ResetBweBitrates() {

[pthatcher1, 2016/03/16 21:22:03]

If !new_route.connected, we probably want to do something more drastic with the
BWE.  I'm not sure what, though, so perhaps just a TODO for now.

[honghaiz3, 2016/03/17 03:38:27]

Done. Add TODO.

+  LOG(LS_INFO) << "Reset BWE estimate to "
+               << config_.bitrate_config.start_bitrate_bps << "bps";
+  congestion_controller_->SetBweBitrates(
+      config_.bitrate_config.min_bitrate_bps,
+      config_.bitrate_config.start_bitrate_bps,
+      config_.bitrate_config.max_bitrate_bps);

[pthatcher1, 2016/03/16 21:22:03]

Does this really restart the BWE?  

[honghaiz3, 2016/03/17 03:38:27]

Actually It may not. Maybe we can leave this to BWE experts. 

+}
+
 void Call::OnSentPacket(const rtc::SentPacket& sent_packet) {
   if (first_packet_sent_ms_ == -1)
     first_packet_sent_ms_ = clock_->TimeInMilliseconds();