Adding BitrateController to audio network adaptor.

webrtc/modules/audio_coding/audio_network_adaptor/bitrate_controller_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 "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/modules/audio_coding/audio_network_adaptor/bitrate_controller.h"
+
+namespace webrtc {
+
+namespace {
+
+// L2(14B) + IPv4(20B) + UDP(8B) + RTP(12B) + SRTP_AUTH(10B) = 64B = 512 bits
+constexpr int kPacketOverheadBits = 512;
+
+void CheckDecision(BitrateController* controller,
+                   const rtc::Optional<int>& target_audio_bitrate_bps,
+                   const rtc::Optional<int>& frame_length_ms,
+                   int expected_bitrate_bps) {
+  Controller::NetworkMetrics metrics;
+  metrics.target_audio_bitrate_bps = target_audio_bitrate_bps;
+  AudioNetworkAdaptor::EncoderRuntimeConfig config;
+  config.frame_length_ms = frame_length_ms;
+  controller->MakeDecision(metrics, &config);
+  EXPECT_EQ(rtc::Optional<int>(expected_bitrate_bps), config.bitrate_bps);
+}
+
+}  // namespace
+
+// These tests are named AnaBitrateControllerTest to distinguish from
+// BitrateControllerTest in
+// modules/bitrate_controller/bitrate_controller_unittest.cc.
+
+TEST(AnaBitrateControllerTest, OutputInitValueWhenTargetBitrateUnknown) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+  CheckDecision(&controller, rtc::Optional<int>(),
+                rtc::Optional<int>(kInitialFrameLengthMs * 2),
+                kInitialBitrateBps);
+}
+
+TEST(AnaBitrateControllerTest, ChangeBitrateOnTargetBitrateChanged) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+  constexpr int kTargetBitrateBps = 48000;
+  // Frame length unchanged, bitrate changes in accordance with
+  // |metrics.target_audio_bitrate_bps|
+  CheckDecision(&controller, rtc::Optional<int>(kTargetBitrateBps),
+                rtc::Optional<int>(kInitialFrameLengthMs), kTargetBitrateBps);
+}
+
+TEST(AnaBitrateControllerTest, TreatUnknownFrameLengthAsFrameLengthUnchanged) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+  constexpr int kTargetBitrateBps = 48000;
+  CheckDecision(&controller, rtc::Optional<int>(kTargetBitrateBps),
+                rtc::Optional<int>(), kTargetBitrateBps);
+}
+
+TEST(AnaBitrateControllerTest, IncreaseBitrateOnFrameLengthIncreased) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+  constexpr int kFrameLengthMs = 60;
+  constexpr int kPacketOverheadRateDiff =
+      kPacketOverheadBits * 1000 / kInitialFrameLengthMs -
+      kPacketOverheadBits * 1000 / kFrameLengthMs;
+  CheckDecision(&controller, rtc::Optional<int>(kInitialBitrateBps),
+                rtc::Optional<int>(kFrameLengthMs),
+                kInitialBitrateBps + kPacketOverheadRateDiff);
+}
+
+TEST(AnaBitrateControllerTest, DecreaseBitrateOnFrameLengthDecreased) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 60;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+  constexpr int kFrameLengthMs = 20;
+  constexpr int kPacketOverheadRateDiff =
+      kPacketOverheadBits * 1000 / kInitialFrameLengthMs -
+      kPacketOverheadBits * 1000 / kFrameLengthMs;
+  CheckDecision(&controller, rtc::Optional<int>(kInitialBitrateBps),
+                rtc::Optional<int>(kFrameLengthMs),
+                kInitialBitrateBps + kPacketOverheadRateDiff);
+}
+
+TEST(AnaBitrateControllerTest, CheckBehaviorOnChangingCondition) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+
+  int last_overhead_bitrate =
+      kPacketOverheadBits * 1000 / kInitialFrameLengthMs;
+  int current_overhead_bitrate = kPacketOverheadBits * 1000 / 20;
+  // Start from an arbitrary overall bitrate.
+  int overall_bitrate = 34567;
+  CheckDecision(
+      &controller, rtc::Optional<int>(overall_bitrate - last_overhead_bitrate),
+      rtc::Optional<int>(20), overall_bitrate - current_overhead_bitrate);
+
+  // Next: increase overall bitrate.
+  overall_bitrate += 100;
+  CheckDecision(
+      &controller, rtc::Optional<int>(overall_bitrate - last_overhead_bitrate),
+      rtc::Optional<int>(20), overall_bitrate - current_overhead_bitrate);
+
+  // Next: change frame length.
+  current_overhead_bitrate = kPacketOverheadBits * 1000 / 60;
+  CheckDecision(
+      &controller, rtc::Optional<int>(overall_bitrate - last_overhead_bitrate),
+      rtc::Optional<int>(60), overall_bitrate - current_overhead_bitrate);
+  last_overhead_bitrate = current_overhead_bitrate;
+
+  // Next: change frame length.
+  current_overhead_bitrate = kPacketOverheadBits * 1000 / 20;
+  CheckDecision(
+      &controller, rtc::Optional<int>(overall_bitrate - last_overhead_bitrate),
+      rtc::Optional<int>(20), overall_bitrate - current_overhead_bitrate);
+  last_overhead_bitrate = current_overhead_bitrate;
+
+  // Next: decrease overall bitrate and frame length.
+  overall_bitrate -= 100;
+  current_overhead_bitrate = kPacketOverheadBits * 1000 / 60;
+  CheckDecision(
+      &controller, rtc::Optional<int>(overall_bitrate - last_overhead_bitrate),
+      rtc::Optional<int>(60), overall_bitrate - current_overhead_bitrate);
+}
+
+}  // namespace webrtc