Reduce the BWE with 50% when feedback is received too late.

webrtc/modules/remote_bitrate_estimator/aimd_rate_control_unittest.cc

 /*
  *  Copyright (c) 2016 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.
  */
 #include <memory>
@@ skipping 12 matching lines @@
   std::unique_ptr<SimulatedClock> simulated_clock;
 };
 
 AimdRateControlStates CreateAimdRateControlStates() {
   AimdRateControlStates states;
   states.aimd_rate_control.reset(new AimdRateControl());
   states.simulated_clock.reset(new SimulatedClock(kClockInitialTime));
   return states;
 }
 
-void InitBitrate(const AimdRateControlStates& states,
-                 int bitrate,
-                 int64_t now_ms) {
-  // Reduce the bitrate by 1000 to compensate for the Update after SetEstimate.
-  bitrate -= 1000;
-
-  states.aimd_rate_control->SetEstimate(bitrate, now_ms);
-}
-
 void UpdateRateControl(const AimdRateControlStates& states,
                        const BandwidthUsage& bandwidth_usage,
                        int bitrate,
                        int64_t now_ms) {
   RateControlInput input(bandwidth_usage, rtc::Optional<uint32_t>(bitrate),
                          now_ms);
   states.aimd_rate_control->Update(&input, now_ms);
   states.aimd_rate_control->UpdateBandwidthEstimate(now_ms);
 }
 
 }  // namespace
 
 TEST(AimdRateControlTest, MinNearMaxIncreaseRateOnLowBandwith) {
   auto states = CreateAimdRateControlStates();
   constexpr int kBitrate = 30000;
-  InitBitrate(states, kBitrate, states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kBitrate, states.simulated_clock->TimeInMilliseconds());
   EXPECT_EQ(4000, states.aimd_rate_control->GetNearMaxIncreaseRateBps());
 }
 
 TEST(AimdRateControlTest, NearMaxIncreaseRateIs5kbpsOn90kbpsAnd200msRtt) {
   auto states = CreateAimdRateControlStates();
   constexpr int kBitrate = 90000;
-  InitBitrate(states, kBitrate, states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kBitrate, states.simulated_clock->TimeInMilliseconds());
   EXPECT_EQ(5000, states.aimd_rate_control->GetNearMaxIncreaseRateBps());
 }
 
 TEST(AimdRateControlTest, NearMaxIncreaseRateIs5kbpsOn60kbpsAnd100msRtt) {
   auto states = CreateAimdRateControlStates();
   constexpr int kBitrate = 60000;
-  InitBitrate(states, kBitrate, states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kBitrate, states.simulated_clock->TimeInMilliseconds());
   states.aimd_rate_control->SetRtt(100);
   EXPECT_EQ(5000, states.aimd_rate_control->GetNearMaxIncreaseRateBps());
 }
 
 TEST(AimdRateControlTest, UnknownBitrateDecreaseBeforeFirstOveruse) {
   auto states = CreateAimdRateControlStates();
   EXPECT_EQ(rtc::Optional<int>(),
             states.aimd_rate_control->GetLastBitrateDecreaseBps());
 }
 
 TEST(AimdRateControlTest, GetLastBitrateDecrease) {
   auto states = CreateAimdRateControlStates();
   constexpr int kBitrate = 300000;
-  InitBitrate(states, kBitrate, states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kBitrate, states.simulated_clock->TimeInMilliseconds());
   UpdateRateControl(states, kBwOverusing, kBitrate - 2000,
                     states.simulated_clock->TimeInMilliseconds());
   EXPECT_EQ(rtc::Optional<int>(46700),
             states.aimd_rate_control->GetLastBitrateDecreaseBps());
 }
 
 TEST(AimdRateControlTest, BweLimitedByAckedBitrate) {
   auto states = CreateAimdRateControlStates();
   constexpr int kAckedBitrate = 10000;
-  InitBitrate(states, kAckedBitrate,
-              states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kAckedBitrate, states.simulated_clock->TimeInMilliseconds());
   while (states.simulated_clock->TimeInMilliseconds() - kClockInitialTime <
          20000) {
     UpdateRateControl(states, kBwNormal, kAckedBitrate,
                       states.simulated_clock->TimeInMilliseconds());
     states.simulated_clock->AdvanceTimeMilliseconds(100);
   }
   ASSERT_TRUE(states.aimd_rate_control->ValidEstimate());
   EXPECT_EQ(static_cast<uint32_t>(1.5 * kAckedBitrate + 10000),
             states.aimd_rate_control->LatestEstimate());
 }
 
 TEST(AimdRateControlTest, BweNotLimitedByDecreasingAckedBitrate) {
   auto states = CreateAimdRateControlStates();
   constexpr int kAckedBitrate = 100000;
-  InitBitrate(states, kAckedBitrate,
-              states.simulated_clock->TimeInMilliseconds());
+  states.aimd_rate_control->SetEstimate(
+      kAckedBitrate, states.simulated_clock->TimeInMilliseconds());
   while (states.simulated_clock->TimeInMilliseconds() - kClockInitialTime <
          20000) {
     UpdateRateControl(states, kBwNormal, kAckedBitrate,
                       states.simulated_clock->TimeInMilliseconds());
     states.simulated_clock->AdvanceTimeMilliseconds(100);
   }
   ASSERT_TRUE(states.aimd_rate_control->ValidEstimate());
   // If the acked bitrate decreases the BWE shouldn't be reduced to 1.5x
   // what's being acked, but also shouldn't get to increase more.
   uint32_t prev_estimate = states.aimd_rate_control->LatestEstimate();
   UpdateRateControl(states, kBwNormal, kAckedBitrate / 2,
                     states.simulated_clock->TimeInMilliseconds());
   uint32_t new_estimate = states.aimd_rate_control->LatestEstimate();
   EXPECT_NEAR(new_estimate, static_cast<uint32_t>(1.5 * kAckedBitrate + 10000),
               2000);
   EXPECT_EQ(new_estimate, prev_estimate);
 }
 }  // namespace webrtc