Now probe for x3 and x6 the initial start bitrate.

webrtc/modules/congestion_controller/congestion_controller.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 154 matching lines @@
       remote_bitrate_estimator_(
           new WrappingBitrateEstimator(remote_bitrate_observer, clock_)),
       bitrate_controller_(
           BitrateController::CreateBitrateController(clock_, event_log)),
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
       transport_feedback_adapter_(bitrate_controller_.get(), clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       max_bitrate_bps_(0),
+      initial_probing_triggered_(false),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
       last_reported_rtt_(0),
       network_state_(kNetworkUp) {
   Init();
 }
 
 CongestionController::CongestionController(
     Clock* clock,
     Observer* observer,
@@ skipping 10 matching lines @@
       // Constructed last as this object calls the provided callback on
       // construction.
       bitrate_controller_(
           BitrateController::CreateBitrateController(clock_, event_log)),
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
       transport_feedback_adapter_(bitrate_controller_.get(), clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       max_bitrate_bps_(0),
+      initial_probing_triggered_(false),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
       last_reported_rtt_(0),
       network_state_(kNetworkUp) {
   Init();
 }
 
 CongestionController::~CongestionController() {}
 
 void CongestionController::Init() {
   transport_feedback_adapter_.SetBitrateEstimator(
       new DelayBasedBwe(&transport_feedback_adapter_, clock_));
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
-  pacer_->CreateProbeCluster(900000, 6);
-  pacer_->CreateProbeCluster(1800000, 5);
 }
 
 void CongestionController::SetBweBitrates(int min_bitrate_bps,
                                           int start_bitrate_bps,
                                           int max_bitrate_bps) {
   ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
   bitrate_controller_->SetBitrates(start_bitrate_bps,
                                    min_bitrate_bps,
                                    max_bitrate_bps);
 
   {
+    rtc::CritScope cs(&critsect_);
+    if (!initial_probing_triggered_) {
+      pacer_->CreateProbeCluster(start_bitrate_bps * 3, 6);
+      pacer_->CreateProbeCluster(start_bitrate_bps * 6, 5);
+      initial_probing_triggered_ = true;
+    }
+
     // Only do probing if:
     //   - we are mid-call, which we consider to be if
     //     |last_reported_bitrate_bps_| != 0, and
     //   - the current bitrate is lower than the new |max_bitrate_bps|, and
     //   - we actually want to increase the |max_bitrate_bps_|.
-    rtc::CritScope cs(&critsect_);
     if (last_reported_bitrate_bps_ != 0 &&
         last_reported_bitrate_bps_ < static_cast<uint32_t>(max_bitrate_bps) &&
         max_bitrate_bps > max_bitrate_bps_) {
       pacer_->CreateProbeCluster(max_bitrate_bps, 5);
     }
   }
   max_bitrate_bps_ = max_bitrate_bps;
 
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
@@ skipping 139 matching lines @@
 bool CongestionController::IsSendQueueFull() const {
   return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
 }
 
 bool CongestionController::IsNetworkDown() const {
   rtc::CritScope cs(&critsect_);
   return network_state_ == kNetworkDown;
 }
 
 }  // namespace webrtc