modules/audio_coding/audio_network_adaptor/fec_controller_plr_based_unittest.cc - src - Git at Google

 /*
  *  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 "modules/audio_coding/audio_network_adaptor/fec_controller_plr_based.h"

 #include <utility>

 #include "common_audio/mocks/mock_smoothing_filter.h"
 #include "test/gtest.h"

 namespace webrtc {

 using ::testing::_;
 using ::testing::NiceMock;
 using ::testing::Return;

 namespace {

 // The test uses the following settings:
 //
 // packet-loss ^   |  |
 //             |  A| C|   FEC
 //             |    \  \   ON
 //             | FEC \ D\_______
 //             | OFF B\_________
 //             |-----------------> bandwidth
 //
 // A : (kDisablingBandwidthLow, kDisablingPacketLossAtLowBw)
 // B : (kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw)
 // C : (kEnablingBandwidthLow, kEnablingPacketLossAtLowBw)
 // D : (kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw)

 constexpr int kDisablingBandwidthLow = 15000;
 constexpr float kDisablingPacketLossAtLowBw = 0.08f;
 constexpr int kDisablingBandwidthHigh = 64000;
 constexpr float kDisablingPacketLossAtHighBw = 0.01f;
 constexpr int kEnablingBandwidthLow = 17000;
 constexpr float kEnablingPacketLossAtLowBw = 0.1f;
 constexpr int kEnablingBandwidthHigh = 64000;
 constexpr float kEnablingPacketLossAtHighBw = 0.05f;

 constexpr float kEpsilon = 1e-5f;

 struct FecControllerPlrBasedTestStates {
   std::unique_ptr<FecControllerPlrBased> controller;
   MockSmoothingFilter* packet_loss_smoother;
 };

 FecControllerPlrBasedTestStates CreateFecControllerPlrBased(
     bool initial_fec_enabled,
     const ThresholdCurve& enabling_curve,
     const ThresholdCurve& disabling_curve) {
   FecControllerPlrBasedTestStates states;
   std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
       new NiceMock<MockSmoothingFilter>());
   states.packet_loss_smoother = mock_smoothing_filter.get();
   states.controller.reset(new FecControllerPlrBased(
       FecControllerPlrBased::Config(initial_fec_enabled, enabling_curve,
                                     disabling_curve, 0),
       std::move(mock_smoothing_filter)));
   return states;
 }

 FecControllerPlrBasedTestStates CreateFecControllerPlrBased(
     bool initial_fec_enabled) {
   return CreateFecControllerPlrBased(
       initial_fec_enabled,
       ThresholdCurve(kEnablingBandwidthLow, kEnablingPacketLossAtLowBw,
                      kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw),
       ThresholdCurve(kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
                      kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw));
 }

 void UpdateNetworkMetrics(FecControllerPlrBasedTestStates* states,
                           const absl::optional<int>& uplink_bandwidth_bps,
                           const absl::optional<float>& uplink_packet_loss) {
   // UpdateNetworkMetrics can accept multiple network metric updates at once.
   // However, currently, the most used case is to update one metric at a time.
   // To reflect this fact, we separate the calls.
   if (uplink_bandwidth_bps) {
     Controller::NetworkMetrics network_metrics;
     network_metrics.uplink_bandwidth_bps = uplink_bandwidth_bps;
     states->controller->UpdateNetworkMetrics(network_metrics);
   }
   if (uplink_packet_loss) {
     Controller::NetworkMetrics network_metrics;
     network_metrics.uplink_packet_loss_fraction = uplink_packet_loss;
     EXPECT_CALL(*states->packet_loss_smoother, AddSample(*uplink_packet_loss));
     states->controller->UpdateNetworkMetrics(network_metrics);
     // This is called during CheckDecision().
     EXPECT_CALL(*states->packet_loss_smoother, GetAverage())
         .WillOnce(Return(*uplink_packet_loss));
   }
 }

 // Checks that the FEC decision and `uplink_packet_loss_fraction` given by
 // `states->controller->MakeDecision` matches `expected_enable_fec` and
 // `expected_uplink_packet_loss_fraction`, respectively.
 void CheckDecision(FecControllerPlrBasedTestStates* states,
                    bool expected_enable_fec,
                    float expected_uplink_packet_loss_fraction) {
   AudioEncoderRuntimeConfig config;
   states->controller->MakeDecision(&config);
   EXPECT_EQ(expected_enable_fec, config.enable_fec);
   EXPECT_EQ(expected_uplink_packet_loss_fraction,
             config.uplink_packet_loss_fraction);
 }

 }  // namespace

 TEST(FecControllerPlrBasedTest, OutputInitValueBeforeAnyInputsAreReceived) {
   for (bool initial_fec_enabled : {false, true}) {
     auto states = CreateFecControllerPlrBased(initial_fec_enabled);
     CheckDecision(&states, initial_fec_enabled, 0);
   }
 }

 TEST(FecControllerPlrBasedTest, OutputInitValueWhenUplinkBandwidthUnknown) {
   // Regardless of the initial FEC state and the packet-loss rate,
   // the initial FEC state is maintained as long as the BWE is unknown.
   for (bool initial_fec_enabled : {false, true}) {
     for (float packet_loss :
          {kDisablingPacketLossAtLowBw - kEpsilon, kDisablingPacketLossAtLowBw,
           kDisablingPacketLossAtLowBw + kEpsilon,
           kEnablingPacketLossAtLowBw - kEpsilon, kEnablingPacketLossAtLowBw,
           kEnablingPacketLossAtLowBw + kEpsilon}) {
       auto states = CreateFecControllerPlrBased(initial_fec_enabled);
       UpdateNetworkMetrics(&states, absl::nullopt, packet_loss);
       CheckDecision(&states, initial_fec_enabled, packet_loss);
     }
   }
 }

 TEST(FecControllerPlrBasedTest,
      OutputInitValueWhenUplinkPacketLossFractionUnknown) {
   // Regardless of the initial FEC state and the BWE, the initial FEC state
   // is maintained as long as the packet-loss rate is unknown.
   for (bool initial_fec_enabled : {false, true}) {
     for (int bandwidth : {kDisablingBandwidthLow - 1, kDisablingBandwidthLow,
                           kDisablingBandwidthLow + 1, kEnablingBandwidthLow - 1,
                           kEnablingBandwidthLow, kEnablingBandwidthLow + 1}) {
       auto states = CreateFecControllerPlrBased(initial_fec_enabled);
       UpdateNetworkMetrics(&states, bandwidth, absl::nullopt);
       CheckDecision(&states, initial_fec_enabled, 0.0);
     }
   }
 }

 TEST(FecControllerPlrBasedTest, EnableFecForHighBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
                        kEnablingPacketLossAtHighBw);
   CheckDecision(&states, true, kEnablingPacketLossAtHighBw);
 }

 TEST(FecControllerPlrBasedTest, UpdateMultipleNetworkMetricsAtOnce) {
   // This test is similar to EnableFecForHighBandwidth. But instead of
   // using ::UpdateNetworkMetrics(...), which calls
   // FecControllerPlrBased::UpdateNetworkMetrics(...) multiple times, we
   // we call it only once. This is to verify that
   // FecControllerPlrBased::UpdateNetworkMetrics(...) can handle multiple
   // network updates at once. This is, however, not a common use case in current
   // audio_network_adaptor_impl.cc.
   auto states = CreateFecControllerPlrBased(false);
   Controller::NetworkMetrics network_metrics;
   network_metrics.uplink_bandwidth_bps = kEnablingBandwidthHigh;
   network_metrics.uplink_packet_loss_fraction = kEnablingPacketLossAtHighBw;
   EXPECT_CALL(*states.packet_loss_smoother, GetAverage())
       .WillOnce(Return(kEnablingPacketLossAtHighBw));
   states.controller->UpdateNetworkMetrics(network_metrics);
   CheckDecision(&states, true, kEnablingPacketLossAtHighBw);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOffForHighBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   constexpr float kPacketLoss = kEnablingPacketLossAtHighBw * 0.99f;
   UpdateNetworkMetrics(&states, kEnablingBandwidthHigh, kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, EnableFecForMediumBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   constexpr float kPacketLoss =
       (kEnablingPacketLossAtLowBw + kEnablingPacketLossAtHighBw) / 2.0;
   UpdateNetworkMetrics(&states,
                        (kEnablingBandwidthHigh + kEnablingBandwidthLow) / 2,
                        kPacketLoss);
   CheckDecision(&states, true, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOffForMediumBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   constexpr float kPacketLoss =
       kEnablingPacketLossAtLowBw * 0.49f + kEnablingPacketLossAtHighBw * 0.51f;
   UpdateNetworkMetrics(&states,
                        (kEnablingBandwidthHigh + kEnablingBandwidthLow) / 2,
                        kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, EnableFecForLowBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
                        kEnablingPacketLossAtLowBw);
   CheckDecision(&states, true, kEnablingPacketLossAtLowBw);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOffForLowBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   constexpr float kPacketLoss = kEnablingPacketLossAtLowBw * 0.99f;
   UpdateNetworkMetrics(&states, kEnablingBandwidthLow, kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOffForVeryLowBandwidth) {
   auto states = CreateFecControllerPlrBased(false);
   // Below `kEnablingBandwidthLow`, no packet loss fraction can cause FEC to
   // turn on.
   UpdateNetworkMetrics(&states, kEnablingBandwidthLow - 1, 1.0);
   CheckDecision(&states, false, 1.0);
 }

 TEST(FecControllerPlrBasedTest, DisableFecForHighBandwidth) {
   auto states = CreateFecControllerPlrBased(true);
   constexpr float kPacketLoss = kDisablingPacketLossAtHighBw - kEpsilon;
   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh, kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOnForHighBandwidth) {
   // Note: Disabling happens when the value is strictly below the threshold.
   auto states = CreateFecControllerPlrBased(true);
   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
                        kDisablingPacketLossAtHighBw);
   CheckDecision(&states, true, kDisablingPacketLossAtHighBw);
 }

 TEST(FecControllerPlrBasedTest, DisableFecOnMediumBandwidth) {
   auto states = CreateFecControllerPlrBased(true);
   constexpr float kPacketLoss =
       (kDisablingPacketLossAtLowBw + kDisablingPacketLossAtHighBw) / 2.0f -
       kEpsilon;
   UpdateNetworkMetrics(&states,
                        (kDisablingBandwidthHigh + kDisablingBandwidthLow) / 2,
                        kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, MaintainFecOnForMediumBandwidth) {
   auto states = CreateFecControllerPlrBased(true);
   constexpr float kPacketLoss = kDisablingPacketLossAtLowBw * 0.51f +
                                 kDisablingPacketLossAtHighBw * 0.49f - kEpsilon;
   UpdateNetworkMetrics(&states,
                        (kEnablingBandwidthHigh + kDisablingBandwidthLow) / 2,
                        kPacketLoss);
   CheckDecision(&states, true, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, DisableFecForLowBandwidth) {
   auto states = CreateFecControllerPlrBased(true);
   constexpr float kPacketLoss = kDisablingPacketLossAtLowBw - kEpsilon;
   UpdateNetworkMetrics(&states, kDisablingBandwidthLow, kPacketLoss);
   CheckDecision(&states, false, kPacketLoss);
 }

 TEST(FecControllerPlrBasedTest, DisableFecForVeryLowBandwidth) {
   auto states = CreateFecControllerPlrBased(true);
   // Below `kEnablingBandwidthLow`, any packet loss fraction can cause FEC to
   // turn off.
   UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
   CheckDecision(&states, false, 1.0);
 }

 TEST(FecControllerPlrBasedTest, CheckBehaviorOnChangingNetworkMetrics) {
   // In this test, we let the network metrics to traverse from 1 to 5.
   // packet-loss ^ 1 |  |
   //             |   | 2|
   //             |    \  \ 3
   //             |     \4 \_______
   //             |      \_________
   //             |---------5-------> bandwidth

   auto states = CreateFecControllerPlrBased(true);
   UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
   CheckDecision(&states, false, 1.0);

   UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
                        kEnablingPacketLossAtLowBw * 0.99f);
   CheckDecision(&states, false, kEnablingPacketLossAtLowBw * 0.99f);

   UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
                        kEnablingPacketLossAtHighBw);
   CheckDecision(&states, true, kEnablingPacketLossAtHighBw);

   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
                        kDisablingPacketLossAtHighBw);
   CheckDecision(&states, true, kDisablingPacketLossAtHighBw);

   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh + 1, 0.0);
   CheckDecision(&states, false, 0.0);
 }

 TEST(FecControllerPlrBasedTest, CheckBehaviorOnSpecialCurves) {
   // We test a special configuration, where the points to define the FEC
   // enabling/disabling curves are placed like the following, otherwise the test
   // is the same as CheckBehaviorOnChangingNetworkMetrics.
   //
   // packet-loss ^   |  |
   //             |   | C|
   //             |   |  |
   //             |   | D|_______
   //             |  A|___B______
   //             |-----------------> bandwidth

   constexpr int kEnablingBandwidthHigh = kEnablingBandwidthLow;
   constexpr float kDisablingPacketLossAtLowBw = kDisablingPacketLossAtHighBw;
   FecControllerPlrBasedTestStates states;
   std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
       new NiceMock<MockSmoothingFilter>());
   states.packet_loss_smoother = mock_smoothing_filter.get();
   states.controller.reset(new FecControllerPlrBased(
       FecControllerPlrBased::Config(
           true,
           ThresholdCurve(kEnablingBandwidthLow, kEnablingPacketLossAtLowBw,
                          kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw),
           ThresholdCurve(kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
                          kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw),
           0),
       std::move(mock_smoothing_filter)));

   UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
   CheckDecision(&states, false, 1.0);

   UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
                        kEnablingPacketLossAtHighBw * 0.99f);
   CheckDecision(&states, false, kEnablingPacketLossAtHighBw * 0.99f);

   UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
                        kEnablingPacketLossAtHighBw);
   CheckDecision(&states, true, kEnablingPacketLossAtHighBw);

   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
                        kDisablingPacketLossAtHighBw);
   CheckDecision(&states, true, kDisablingPacketLossAtHighBw);

   UpdateNetworkMetrics(&states, kDisablingBandwidthHigh + 1, 0.0);
   CheckDecision(&states, false, 0.0);
 }

 TEST(FecControllerPlrBasedTest, SingleThresholdCurveForEnablingAndDisabling) {
   // Note: To avoid numerical errors, keep kPacketLossAtLowBw and
   // kPacketLossAthighBw as (negative) integer powers of 2.
   // This is mostly relevant for the O3 case.
   constexpr int kBandwidthLow = 10000;
   constexpr float kPacketLossAtLowBw = 0.25f;
   constexpr int kBandwidthHigh = 20000;
   constexpr float kPacketLossAtHighBw = 0.125f;
   auto curve = ThresholdCurve(kBandwidthLow, kPacketLossAtLowBw, kBandwidthHigh,
                               kPacketLossAtHighBw);

   // B* stands for "below-curve", O* for "on-curve", and A* for "above-curve".
   //
   //                                            //
   // packet-loss ^                              //
   //             |    |                         //
   //             | B1 O1                        //
   //             |    |                         //
   //             |    O2                        //
   //             |     \ A1                     //
   //             |      \                       //
   //             |       O3   A2                //
   //             |     B2 \                     //
   //             |         \                    //
   //             |          O4--O5----          //
   //             |                              //
   //             |            B3                //
   //             |-----------------> bandwidth  //

   struct NetworkState {
     int bandwidth;
     float packet_loss;
   };

   std::vector<NetworkState> below{
       {kBandwidthLow - 1, kPacketLossAtLowBw + 0.1f},  // B1
       {(kBandwidthLow + kBandwidthHigh) / 2,
        (kPacketLossAtLowBw + kPacketLossAtHighBw) / 2 - kEpsilon},  // B2
       {kBandwidthHigh + 1, kPacketLossAtHighBw - kEpsilon}          // B3
   };

   std::vector<NetworkState> on{
       {kBandwidthLow, kPacketLossAtLowBw + 0.1f},  // O1
       {kBandwidthLow, kPacketLossAtLowBw},         // O2
       {(kBandwidthLow + kBandwidthHigh) / 2,
        (kPacketLossAtLowBw + kPacketLossAtHighBw) / 2},  // O3
       {kBandwidthHigh, kPacketLossAtHighBw},             // O4
       {kBandwidthHigh + 1, kPacketLossAtHighBw},         // O5
   };

   std::vector<NetworkState> above{
       {(kBandwidthLow + kBandwidthHigh) / 2,
        (kPacketLossAtLowBw + kPacketLossAtHighBw) / 2 + kEpsilon},  // A1
       {kBandwidthHigh + 1, kPacketLossAtHighBw + kEpsilon},         // A2
   };

   // Test that FEC is turned off whenever we're below the curve, independent
   // of the starting FEC state.
   for (NetworkState net_state : below) {
     for (bool initial_fec_enabled : {false, true}) {
       auto states =
           CreateFecControllerPlrBased(initial_fec_enabled, curve, curve);
       UpdateNetworkMetrics(&states, net_state.bandwidth, net_state.packet_loss);
       CheckDecision(&states, false, net_state.packet_loss);
     }
   }

   // Test that FEC is turned on whenever we're on the curve or above it,
   // independent of the starting FEC state.
   for (const std::vector<NetworkState>& states_list : {on, above}) {
     for (NetworkState net_state : states_list) {
       for (bool initial_fec_enabled : {false, true}) {
         auto states =
             CreateFecControllerPlrBased(initial_fec_enabled, curve, curve);
         UpdateNetworkMetrics(&states, net_state.bandwidth,
                              net_state.packet_loss);
         CheckDecision(&states, true, net_state.packet_loss);
       }
     }
   }
 }

 TEST(FecControllerPlrBasedTest, FecAlwaysOff) {
   ThresholdCurve always_off_curve(0, 1.0f + kEpsilon, 0, 1.0f + kEpsilon);
   for (bool initial_fec_enabled : {false, true}) {
     for (int bandwidth : {0, 10000}) {
       for (float packet_loss : {0.0f, 0.5f, 1.0f}) {
         auto states = CreateFecControllerPlrBased(
             initial_fec_enabled, always_off_curve, always_off_curve);
         UpdateNetworkMetrics(&states, bandwidth, packet_loss);
         CheckDecision(&states, false, packet_loss);
       }
     }
   }
 }

 TEST(FecControllerPlrBasedTest, FecAlwaysOn) {
   ThresholdCurve always_on_curve(0, 0.0f, 0, 0.0f);
   for (bool initial_fec_enabled : {false, true}) {
     for (int bandwidth : {0, 10000}) {
       for (float packet_loss : {0.0f, 0.5f, 1.0f}) {
         auto states = CreateFecControllerPlrBased(
             initial_fec_enabled, always_on_curve, always_on_curve);
         UpdateNetworkMetrics(&states, bandwidth, packet_loss);
         CheckDecision(&states, true, packet_loss);
       }
     }
   }
 }

 #if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
 TEST(FecControllerPlrBasedDeathTest, InvalidConfig) {
   FecControllerPlrBasedTestStates states;
   std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
       new NiceMock<MockSmoothingFilter>());
   states.packet_loss_smoother = mock_smoothing_filter.get();
   EXPECT_DEATH(
       states.controller.reset(new FecControllerPlrBased(
           FecControllerPlrBased::Config(
               true,
               ThresholdCurve(kDisablingBandwidthLow - 1,
                              kEnablingPacketLossAtLowBw, kEnablingBandwidthHigh,
                              kEnablingPacketLossAtHighBw),
               ThresholdCurve(
                   kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
                   kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw),
               0),
           std::move(mock_smoothing_filter))),
       "Check failed");
 }
 #endif

 }  // namespace webrtc
	/*
	* 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 "modules/audio_coding/audio_network_adaptor/fec_controller_plr_based.h"

	#include <utility>

	#include "common_audio/mocks/mock_smoothing_filter.h"
	#include "test/gtest.h"

	namespace webrtc {

	using ::testing::_;
	using ::testing::NiceMock;
	using ::testing::Return;

	namespace {

	// The test uses the following settings:
	//
	// packet-loss ^ \| \|
	// \| A\| C\| FEC
	// \| \ \ ON
	// \| FEC \ D\_______
	// \| OFF B\_________
	// \|-----------------> bandwidth
	//
	// A : (kDisablingBandwidthLow, kDisablingPacketLossAtLowBw)
	// B : (kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw)
	// C : (kEnablingBandwidthLow, kEnablingPacketLossAtLowBw)
	// D : (kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw)

	constexpr int kDisablingBandwidthLow = 15000;
	constexpr float kDisablingPacketLossAtLowBw = 0.08f;
	constexpr int kDisablingBandwidthHigh = 64000;
	constexpr float kDisablingPacketLossAtHighBw = 0.01f;
	constexpr int kEnablingBandwidthLow = 17000;
	constexpr float kEnablingPacketLossAtLowBw = 0.1f;
	constexpr int kEnablingBandwidthHigh = 64000;
	constexpr float kEnablingPacketLossAtHighBw = 0.05f;

	constexpr float kEpsilon = 1e-5f;

	struct FecControllerPlrBasedTestStates {
	std::unique_ptr<FecControllerPlrBased> controller;
	MockSmoothingFilter* packet_loss_smoother;
	};

	FecControllerPlrBasedTestStates CreateFecControllerPlrBased(
	bool initial_fec_enabled,
	const ThresholdCurve& enabling_curve,
	const ThresholdCurve& disabling_curve) {
	FecControllerPlrBasedTestStates states;
	std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
	new NiceMock<MockSmoothingFilter>());
	states.packet_loss_smoother = mock_smoothing_filter.get();
	states.controller.reset(new FecControllerPlrBased(
	FecControllerPlrBased::Config(initial_fec_enabled, enabling_curve,
	disabling_curve, 0),
	std::move(mock_smoothing_filter)));
	return states;
	}

	FecControllerPlrBasedTestStates CreateFecControllerPlrBased(
	bool initial_fec_enabled) {
	return CreateFecControllerPlrBased(
	initial_fec_enabled,
	ThresholdCurve(kEnablingBandwidthLow, kEnablingPacketLossAtLowBw,
	kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw),
	ThresholdCurve(kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
	kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw));
	}

	void UpdateNetworkMetrics(FecControllerPlrBasedTestStates* states,
	const absl::optional<int>& uplink_bandwidth_bps,
	const absl::optional<float>& uplink_packet_loss) {
	// UpdateNetworkMetrics can accept multiple network metric updates at once.
	// However, currently, the most used case is to update one metric at a time.
	// To reflect this fact, we separate the calls.
	if (uplink_bandwidth_bps) {
	Controller::NetworkMetrics network_metrics;
	network_metrics.uplink_bandwidth_bps = uplink_bandwidth_bps;
	states->controller->UpdateNetworkMetrics(network_metrics);
	}
	if (uplink_packet_loss) {
	Controller::NetworkMetrics network_metrics;
	network_metrics.uplink_packet_loss_fraction = uplink_packet_loss;
	EXPECT_CALL(states->packet_loss_smoother, AddSample(uplink_packet_loss));
	states->controller->UpdateNetworkMetrics(network_metrics);
	// This is called during CheckDecision().
	EXPECT_CALL(*states->packet_loss_smoother, GetAverage())
	.WillOnce(Return(*uplink_packet_loss));
	}
	}

	// Checks that the FEC decision and `uplink_packet_loss_fraction` given by
	// `states->controller->MakeDecision` matches `expected_enable_fec` and
	// `expected_uplink_packet_loss_fraction`, respectively.
	void CheckDecision(FecControllerPlrBasedTestStates* states,
	bool expected_enable_fec,
	float expected_uplink_packet_loss_fraction) {
	AudioEncoderRuntimeConfig config;
	states->controller->MakeDecision(&config);
	EXPECT_EQ(expected_enable_fec, config.enable_fec);
	EXPECT_EQ(expected_uplink_packet_loss_fraction,
	config.uplink_packet_loss_fraction);
	}

	} // namespace

	TEST(FecControllerPlrBasedTest, OutputInitValueBeforeAnyInputsAreReceived) {
	for (bool initial_fec_enabled : {false, true}) {
	auto states = CreateFecControllerPlrBased(initial_fec_enabled);
	CheckDecision(&states, initial_fec_enabled, 0);
	}
	}

	TEST(FecControllerPlrBasedTest, OutputInitValueWhenUplinkBandwidthUnknown) {
	// Regardless of the initial FEC state and the packet-loss rate,
	// the initial FEC state is maintained as long as the BWE is unknown.
	for (bool initial_fec_enabled : {false, true}) {
	for (float packet_loss :
	{kDisablingPacketLossAtLowBw - kEpsilon, kDisablingPacketLossAtLowBw,
	kDisablingPacketLossAtLowBw + kEpsilon,
	kEnablingPacketLossAtLowBw - kEpsilon, kEnablingPacketLossAtLowBw,
	kEnablingPacketLossAtLowBw + kEpsilon}) {
	auto states = CreateFecControllerPlrBased(initial_fec_enabled);
	UpdateNetworkMetrics(&states, absl::nullopt, packet_loss);
	CheckDecision(&states, initial_fec_enabled, packet_loss);
	}
	}
	}

	TEST(FecControllerPlrBasedTest,
	OutputInitValueWhenUplinkPacketLossFractionUnknown) {
	// Regardless of the initial FEC state and the BWE, the initial FEC state
	// is maintained as long as the packet-loss rate is unknown.
	for (bool initial_fec_enabled : {false, true}) {
	for (int bandwidth : {kDisablingBandwidthLow - 1, kDisablingBandwidthLow,
	kDisablingBandwidthLow + 1, kEnablingBandwidthLow - 1,
	kEnablingBandwidthLow, kEnablingBandwidthLow + 1}) {
	auto states = CreateFecControllerPlrBased(initial_fec_enabled);
	UpdateNetworkMetrics(&states, bandwidth, absl::nullopt);
	CheckDecision(&states, initial_fec_enabled, 0.0);
	}
	}
	}

	TEST(FecControllerPlrBasedTest, EnableFecForHighBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
	kEnablingPacketLossAtHighBw);
	CheckDecision(&states, true, kEnablingPacketLossAtHighBw);
	}

	TEST(FecControllerPlrBasedTest, UpdateMultipleNetworkMetricsAtOnce) {
	// This test is similar to EnableFecForHighBandwidth. But instead of
	// using ::UpdateNetworkMetrics(...), which calls
	// FecControllerPlrBased::UpdateNetworkMetrics(...) multiple times, we
	// we call it only once. This is to verify that
	// FecControllerPlrBased::UpdateNetworkMetrics(...) can handle multiple
	// network updates at once. This is, however, not a common use case in current
	// audio_network_adaptor_impl.cc.
	auto states = CreateFecControllerPlrBased(false);
	Controller::NetworkMetrics network_metrics;
	network_metrics.uplink_bandwidth_bps = kEnablingBandwidthHigh;
	network_metrics.uplink_packet_loss_fraction = kEnablingPacketLossAtHighBw;
	EXPECT_CALL(*states.packet_loss_smoother, GetAverage())
	.WillOnce(Return(kEnablingPacketLossAtHighBw));
	states.controller->UpdateNetworkMetrics(network_metrics);
	CheckDecision(&states, true, kEnablingPacketLossAtHighBw);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOffForHighBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	constexpr float kPacketLoss = kEnablingPacketLossAtHighBw * 0.99f;
	UpdateNetworkMetrics(&states, kEnablingBandwidthHigh, kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, EnableFecForMediumBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	constexpr float kPacketLoss =
	(kEnablingPacketLossAtLowBw + kEnablingPacketLossAtHighBw) / 2.0;
	UpdateNetworkMetrics(&states,
	(kEnablingBandwidthHigh + kEnablingBandwidthLow) / 2,
	kPacketLoss);
	CheckDecision(&states, true, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOffForMediumBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	constexpr float kPacketLoss =
	kEnablingPacketLossAtLowBw * 0.49f + kEnablingPacketLossAtHighBw * 0.51f;
	UpdateNetworkMetrics(&states,
	(kEnablingBandwidthHigh + kEnablingBandwidthLow) / 2,
	kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, EnableFecForLowBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
	kEnablingPacketLossAtLowBw);
	CheckDecision(&states, true, kEnablingPacketLossAtLowBw);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOffForLowBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	constexpr float kPacketLoss = kEnablingPacketLossAtLowBw * 0.99f;
	UpdateNetworkMetrics(&states, kEnablingBandwidthLow, kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOffForVeryLowBandwidth) {
	auto states = CreateFecControllerPlrBased(false);
	// Below `kEnablingBandwidthLow`, no packet loss fraction can cause FEC to
	// turn on.
	UpdateNetworkMetrics(&states, kEnablingBandwidthLow - 1, 1.0);
	CheckDecision(&states, false, 1.0);
	}

	TEST(FecControllerPlrBasedTest, DisableFecForHighBandwidth) {
	auto states = CreateFecControllerPlrBased(true);
	constexpr float kPacketLoss = kDisablingPacketLossAtHighBw - kEpsilon;
	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh, kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOnForHighBandwidth) {
	// Note: Disabling happens when the value is strictly below the threshold.
	auto states = CreateFecControllerPlrBased(true);
	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
	kDisablingPacketLossAtHighBw);
	CheckDecision(&states, true, kDisablingPacketLossAtHighBw);
	}

	TEST(FecControllerPlrBasedTest, DisableFecOnMediumBandwidth) {
	auto states = CreateFecControllerPlrBased(true);
	constexpr float kPacketLoss =
	(kDisablingPacketLossAtLowBw + kDisablingPacketLossAtHighBw) / 2.0f -
	kEpsilon;
	UpdateNetworkMetrics(&states,
	(kDisablingBandwidthHigh + kDisablingBandwidthLow) / 2,
	kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, MaintainFecOnForMediumBandwidth) {
	auto states = CreateFecControllerPlrBased(true);
	constexpr float kPacketLoss = kDisablingPacketLossAtLowBw * 0.51f +
	kDisablingPacketLossAtHighBw * 0.49f - kEpsilon;
	UpdateNetworkMetrics(&states,
	(kEnablingBandwidthHigh + kDisablingBandwidthLow) / 2,
	kPacketLoss);
	CheckDecision(&states, true, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, DisableFecForLowBandwidth) {
	auto states = CreateFecControllerPlrBased(true);
	constexpr float kPacketLoss = kDisablingPacketLossAtLowBw - kEpsilon;
	UpdateNetworkMetrics(&states, kDisablingBandwidthLow, kPacketLoss);
	CheckDecision(&states, false, kPacketLoss);
	}

	TEST(FecControllerPlrBasedTest, DisableFecForVeryLowBandwidth) {
	auto states = CreateFecControllerPlrBased(true);
	// Below `kEnablingBandwidthLow`, any packet loss fraction can cause FEC to
	// turn off.
	UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
	CheckDecision(&states, false, 1.0);
	}

	TEST(FecControllerPlrBasedTest, CheckBehaviorOnChangingNetworkMetrics) {
	// In this test, we let the network metrics to traverse from 1 to 5.
	// packet-loss ^ 1 \| \|
	// \| \| 2\|
	// \| \ \ 3
	// \| \4 \_______
	// \| \_________
	// \|---------5-------> bandwidth

	auto states = CreateFecControllerPlrBased(true);
	UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
	CheckDecision(&states, false, 1.0);

	UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
	kEnablingPacketLossAtLowBw * 0.99f);
	CheckDecision(&states, false, kEnablingPacketLossAtLowBw * 0.99f);

	UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
	kEnablingPacketLossAtHighBw);
	CheckDecision(&states, true, kEnablingPacketLossAtHighBw);

	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
	kDisablingPacketLossAtHighBw);
	CheckDecision(&states, true, kDisablingPacketLossAtHighBw);

	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh + 1, 0.0);
	CheckDecision(&states, false, 0.0);
	}

	TEST(FecControllerPlrBasedTest, CheckBehaviorOnSpecialCurves) {
	// We test a special configuration, where the points to define the FEC
	// enabling/disabling curves are placed like the following, otherwise the test
	// is the same as CheckBehaviorOnChangingNetworkMetrics.
	//
	// packet-loss ^ \| \|
	// \| \| C\|
	// \| \| \|
	// \| \| D\|_______
	// \| A\|___B______
	// \|-----------------> bandwidth

	constexpr int kEnablingBandwidthHigh = kEnablingBandwidthLow;
	constexpr float kDisablingPacketLossAtLowBw = kDisablingPacketLossAtHighBw;
	FecControllerPlrBasedTestStates states;
	std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
	new NiceMock<MockSmoothingFilter>());
	states.packet_loss_smoother = mock_smoothing_filter.get();
	states.controller.reset(new FecControllerPlrBased(
	FecControllerPlrBased::Config(
	true,
	ThresholdCurve(kEnablingBandwidthLow, kEnablingPacketLossAtLowBw,
	kEnablingBandwidthHigh, kEnablingPacketLossAtHighBw),
	ThresholdCurve(kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
	kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw),
	0),
	std::move(mock_smoothing_filter)));

	UpdateNetworkMetrics(&states, kDisablingBandwidthLow - 1, 1.0);
	CheckDecision(&states, false, 1.0);

	UpdateNetworkMetrics(&states, kEnablingBandwidthLow,
	kEnablingPacketLossAtHighBw * 0.99f);
	CheckDecision(&states, false, kEnablingPacketLossAtHighBw * 0.99f);

	UpdateNetworkMetrics(&states, kEnablingBandwidthHigh,
	kEnablingPacketLossAtHighBw);
	CheckDecision(&states, true, kEnablingPacketLossAtHighBw);

	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh,
	kDisablingPacketLossAtHighBw);
	CheckDecision(&states, true, kDisablingPacketLossAtHighBw);

	UpdateNetworkMetrics(&states, kDisablingBandwidthHigh + 1, 0.0);
	CheckDecision(&states, false, 0.0);
	}

	TEST(FecControllerPlrBasedTest, SingleThresholdCurveForEnablingAndDisabling) {
	// Note: To avoid numerical errors, keep kPacketLossAtLowBw and
	// kPacketLossAthighBw as (negative) integer powers of 2.
	// This is mostly relevant for the O3 case.
	constexpr int kBandwidthLow = 10000;
	constexpr float kPacketLossAtLowBw = 0.25f;
	constexpr int kBandwidthHigh = 20000;
	constexpr float kPacketLossAtHighBw = 0.125f;
	auto curve = ThresholdCurve(kBandwidthLow, kPacketLossAtLowBw, kBandwidthHigh,
	kPacketLossAtHighBw);

	// B* stands for "below-curve", O* for "on-curve", and A* for "above-curve".
	//
	// //
	// packet-loss ^ //
	// \| \| //
	// \| B1 O1 //
	// \| \| //
	// \| O2 //
	// \| \ A1 //
	// \| \ //
	// \| O3 A2 //
	// \| B2 \ //
	// \| \ //
	// \| O4--O5---- //
	// \| //
	// \| B3 //
	// \|-----------------> bandwidth //

	struct NetworkState {
	int bandwidth;
	float packet_loss;
	};

	std::vector<NetworkState> below{
	{kBandwidthLow - 1, kPacketLossAtLowBw + 0.1f}, // B1
	{(kBandwidthLow + kBandwidthHigh) / 2,
	(kPacketLossAtLowBw + kPacketLossAtHighBw) / 2 - kEpsilon}, // B2
	{kBandwidthHigh + 1, kPacketLossAtHighBw - kEpsilon} // B3
	};

	std::vector<NetworkState> on{
	{kBandwidthLow, kPacketLossAtLowBw + 0.1f}, // O1
	{kBandwidthLow, kPacketLossAtLowBw}, // O2
	{(kBandwidthLow + kBandwidthHigh) / 2,
	(kPacketLossAtLowBw + kPacketLossAtHighBw) / 2}, // O3
	{kBandwidthHigh, kPacketLossAtHighBw}, // O4
	{kBandwidthHigh + 1, kPacketLossAtHighBw}, // O5
	};

	std::vector<NetworkState> above{
	{(kBandwidthLow + kBandwidthHigh) / 2,
	(kPacketLossAtLowBw + kPacketLossAtHighBw) / 2 + kEpsilon}, // A1
	{kBandwidthHigh + 1, kPacketLossAtHighBw + kEpsilon}, // A2
	};

	// Test that FEC is turned off whenever we're below the curve, independent
	// of the starting FEC state.
	for (NetworkState net_state : below) {
	for (bool initial_fec_enabled : {false, true}) {
	auto states =
	CreateFecControllerPlrBased(initial_fec_enabled, curve, curve);
	UpdateNetworkMetrics(&states, net_state.bandwidth, net_state.packet_loss);
	CheckDecision(&states, false, net_state.packet_loss);
	}
	}

	// Test that FEC is turned on whenever we're on the curve or above it,
	// independent of the starting FEC state.
	for (const std::vector<NetworkState>& states_list : {on, above}) {
	for (NetworkState net_state : states_list) {
	for (bool initial_fec_enabled : {false, true}) {
	auto states =
	CreateFecControllerPlrBased(initial_fec_enabled, curve, curve);
	UpdateNetworkMetrics(&states, net_state.bandwidth,
	net_state.packet_loss);
	CheckDecision(&states, true, net_state.packet_loss);
	}
	}
	}
	}

	TEST(FecControllerPlrBasedTest, FecAlwaysOff) {
	ThresholdCurve always_off_curve(0, 1.0f + kEpsilon, 0, 1.0f + kEpsilon);
	for (bool initial_fec_enabled : {false, true}) {
	for (int bandwidth : {0, 10000}) {
	for (float packet_loss : {0.0f, 0.5f, 1.0f}) {
	auto states = CreateFecControllerPlrBased(
	initial_fec_enabled, always_off_curve, always_off_curve);
	UpdateNetworkMetrics(&states, bandwidth, packet_loss);
	CheckDecision(&states, false, packet_loss);
	}
	}
	}
	}

	TEST(FecControllerPlrBasedTest, FecAlwaysOn) {
	ThresholdCurve always_on_curve(0, 0.0f, 0, 0.0f);
	for (bool initial_fec_enabled : {false, true}) {
	for (int bandwidth : {0, 10000}) {
	for (float packet_loss : {0.0f, 0.5f, 1.0f}) {
	auto states = CreateFecControllerPlrBased(
	initial_fec_enabled, always_on_curve, always_on_curve);
	UpdateNetworkMetrics(&states, bandwidth, packet_loss);
	CheckDecision(&states, true, packet_loss);
	}
	}
	}
	}

	#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
	TEST(FecControllerPlrBasedDeathTest, InvalidConfig) {
	FecControllerPlrBasedTestStates states;
	std::unique_ptr<MockSmoothingFilter> mock_smoothing_filter(
	new NiceMock<MockSmoothingFilter>());
	states.packet_loss_smoother = mock_smoothing_filter.get();
	EXPECT_DEATH(
	states.controller.reset(new FecControllerPlrBased(
	FecControllerPlrBased::Config(
	true,
	ThresholdCurve(kDisablingBandwidthLow - 1,
	kEnablingPacketLossAtLowBw, kEnablingBandwidthHigh,
	kEnablingPacketLossAtHighBw),
	ThresholdCurve(
	kDisablingBandwidthLow, kDisablingPacketLossAtLowBw,
	kDisablingBandwidthHigh, kDisablingPacketLossAtHighBw),
	0),
	std::move(mock_smoothing_filter))),
	"Check failed");
	}
	#endif

	} // namespace webrtc