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 CheckBitrateControllersDecision(BitrateController* controller,
+                                     const Controller::NetworkMetrics& metrics,
+                                     int frame_length_ms,
+                                     int expected_bitrate_bps) {
+  AudioNetworkAdaptor::EncoderRuntimeConfig config;
+  config.frame_length_ms = rtc::Optional<int>(frame_length_ms);
+  controller->MakeDecision(metrics, &config);
+  EXPECT_EQ(config.bitrate_bps, rtc::Optional<int>(expected_bitrate_bps));

[hlundin-webrtc, 2016/09/15 11:01:09]

Swap parameters. Expected value should go before the test value.

[minyue-webrtc, 2016/09/15 12:12:15]

Ok. There can be a bit more polishing to be made in this test (as the same to
brother CLs), but I will make it in a separate patch set.

+}
+
+}  // 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));
+  Controller::NetworkMetrics metrics;
+  CheckBitrateControllersDecision(
+      &controller, metrics, kInitialFrameLengthMs * 2, kInitialBitrateBps);
+}
+
+TEST(AnaBitrateControllerTest, ChangeBitrateOnTargetBitrateChanged) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+
+  Controller::NetworkMetrics metrics;
+  constexpr int kTargetBitrateBps = 48000;
+  metrics.target_audio_bitrate_bps = rtc::Optional<int>(kTargetBitrateBps);
+
+  // Frame length unchanged, bitrate changes in accordance with
+  // |metrics.target_audio_bitrate_bps|
+  CheckBitrateControllersDecision(&controller, metrics, kInitialFrameLengthMs,
+                                  kTargetBitrateBps);
+}
+
+TEST(AnaBitrateControllerTest, IncreaseBitrateOnFrameLengthIncreased) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 20;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+
+  Controller::NetworkMetrics metrics;
+  metrics.target_audio_bitrate_bps = rtc::Optional<int>(kInitialBitrateBps);
+
+  constexpr int kFrameLengthMs = 60;
+  constexpr int kPacketOverheadRateDiff =
+      kPacketOverheadBits * 1000 / kInitialFrameLengthMs -
+      kPacketOverheadBits * 1000 / kFrameLengthMs;
+  CheckBitrateControllersDecision(&controller, metrics, kFrameLengthMs,
+                                  kInitialBitrateBps + kPacketOverheadRateDiff);
+}
+
+TEST(AnaBitrateControllerTest, DecreaseBitrateOnFrameLengthDecreased) {
+  constexpr int kInitialBitrateBps = 32000;
+  constexpr int kInitialFrameLengthMs = 60;
+  BitrateController controller(
+      BitrateController::Config(kInitialBitrateBps, kInitialFrameLengthMs));
+
+  Controller::NetworkMetrics metrics;
+  metrics.target_audio_bitrate_bps = rtc::Optional<int>(kInitialBitrateBps);
+
+  constexpr int kFrameLengthMs = 20;
+  constexpr int kPacketOverheadRateDiff =
+      kPacketOverheadBits * 1000 / kInitialFrameLengthMs -
+      kPacketOverheadBits * 1000 / kFrameLengthMs;
+  CheckBitrateControllersDecision(&controller, metrics, kFrameLengthMs,
+                                  kInitialBitrateBps + kPacketOverheadRateDiff);
+}
+
+}  // namespace webrtc