Adding ChannelController to audio network adaptor.

BUG=webrtc:6303

Review-Url: https://codereview.webrtc.org/2319873002
Cr-Commit-Position: refs/heads/master@{#14216}

webrtc/modules/audio_coding/BUILD.gn

@@ -703,6 +703,8 @@ source_set("audio_network_adaptor") {
     "audio_network_adaptor/audio_network_adaptor.cc",
     "audio_network_adaptor/audio_network_adaptor_impl.cc",
     "audio_network_adaptor/audio_network_adaptor_impl.h",
+    "audio_network_adaptor/channel_controller.cc",
+    "audio_network_adaptor/channel_controller.h",
     "audio_network_adaptor/controller.cc",
     "audio_network_adaptor/controller.h",
     "audio_network_adaptor/controller_manager.cc",

webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor.gypi

@@ -14,6 +14,8 @@
         'audio_network_adaptor.cc',
         'audio_network_adaptor_impl.cc',
         'audio_network_adaptor_impl.h',
+        'channel_controller.cc',
+        'channel_controller.h',
         'controller.h',
         'controller.cc',
         'controller_manager.cc',

webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.cc

@@ -0,0 +1,56 @@
+/*
+ *  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 <algorithm>
+
+#include "webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.h"
+#include "webrtc/base/checks.h"
+
+namespace webrtc {
+
+ChannelController::Config::Config(size_t num_encoder_channels,
+                                  size_t intial_channels_to_encode,
+                                  int channel_1_to_2_bandwidth_bps,
+                                  int channel_2_to_1_bandwidth_bps)
+    : num_encoder_channels(num_encoder_channels),
+      intial_channels_to_encode(intial_channels_to_encode),
+      channel_1_to_2_bandwidth_bps(channel_1_to_2_bandwidth_bps),
+      channel_2_to_1_bandwidth_bps(channel_2_to_1_bandwidth_bps) {}
+
+ChannelController::ChannelController(const Config& config)
+    : config_(config), channels_to_encode_(config_.intial_channels_to_encode) {
+  RTC_DCHECK_GT(config_.intial_channels_to_encode, 0lu);
+  // Currently, we require |intial_channels_to_encode| to be <= 2.
+  RTC_DCHECK_LE(config_.intial_channels_to_encode, 2lu);
+  RTC_DCHECK_GE(config_.num_encoder_channels,
+                config_.intial_channels_to_encode);
+}
+
+void ChannelController::MakeDecision(
+    const NetworkMetrics& metrics,
+    AudioNetworkAdaptor::EncoderRuntimeConfig* config) {
+  // Decision on |num_channels| should not have been made.
+  RTC_DCHECK(!config->num_channels);
+
+  if (metrics.uplink_bandwidth_bps) {
+    if (channels_to_encode_ == 2 &&
+        *metrics.uplink_bandwidth_bps <= config_.channel_2_to_1_bandwidth_bps) {
+      channels_to_encode_ = 1;
+    } else if (channels_to_encode_ == 1 &&
+               *metrics.uplink_bandwidth_bps >=
+                   config_.channel_1_to_2_bandwidth_bps) {
+      channels_to_encode_ =
+          std::min(static_cast<size_t>(2), config_.num_encoder_channels);
+    }
+  }
+  config->num_channels = rtc::Optional<size_t>(channels_to_encode_);
+}
+
+}  // namespace webrtc

webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.h

@@ -0,0 +1,49 @@
+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_coding/audio_network_adaptor/controller.h"
+
+namespace webrtc {
+
+class ChannelController final : public Controller {
+ public:
+  struct Config {
+    Config(size_t num_encoder_channels,
+           size_t intial_channels_to_encode,
+           int channel_1_to_2_bandwidth_bps,
+           int channel_2_to_1_bandwidth_bps);
+    size_t num_encoder_channels;
+    size_t intial_channels_to_encode;
+    // Uplink bandwidth above which the number of encoded channels should switch
+    // from 1 to 2.
+    int channel_1_to_2_bandwidth_bps;
+    // Uplink bandwidth below which the number of encoded channels should switch
+    // from 2 to 1.
+    int channel_2_to_1_bandwidth_bps;
+  };
+
+  explicit ChannelController(const Config& config);
+
+  void MakeDecision(const NetworkMetrics& metrics,
+                    AudioNetworkAdaptor::EncoderRuntimeConfig* config) override;
+
+ private:
+  const Config config_;
+  size_t channels_to_encode_;
+  RTC_DISALLOW_COPY_AND_ASSIGN(ChannelController);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_CODING_AUDIO_NETWORK_ADAPTOR_CHANNEL_CONTROLLER_H_

webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc

@@ -0,0 +1,113 @@
+/*
+ *  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>
+
+#include "webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+constexpr int kNumChannels = 2;
+constexpr int kChannel1To2BandwidthBps = 31000;
+constexpr int kChannel2To1BandwidthBps = 29000;
+constexpr int kMediumBandwidthBps =
+    (kChannel1To2BandwidthBps + kChannel2To1BandwidthBps) / 2;
+
+std::unique_ptr<ChannelController> CreateChannelController(int init_channels) {
+  std::unique_ptr<ChannelController> controller(
+      new ChannelController(ChannelController::Config(
+          kNumChannels, init_channels, kChannel1To2BandwidthBps,
+          kChannel2To1BandwidthBps)));
+  return controller;
+}
+
+void CheckDecision(ChannelController* controller,
+                   const Controller::NetworkMetrics& metrics,
+                   size_t expected_num_channels) {
+  AudioNetworkAdaptor::EncoderRuntimeConfig config;
+  controller->MakeDecision(metrics, &config);
+  EXPECT_EQ(rtc::Optional<size_t>(expected_num_channels), config.num_channels);
+}
+
+}  // namespace
+
+TEST(ChannelControllerTest, OutputInitValueWhenUplinkBandwidthUnknown) {
+  constexpr int kInitChannels = 2;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+  CheckDecision(controller.get(), metrics, kInitChannels);
+}
+
+TEST(ChannelControllerTest, SwitchTo2ChannelsOnHighUplinkBandwidth) {
+  constexpr int kInitChannels = 1;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+
+  // Use high bandwidth to check output switch to 2.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kChannel1To2BandwidthBps);
+  CheckDecision(controller.get(), metrics, 2);
+}
+
+TEST(ChannelControllerTest, SwitchTo1ChannelOnLowUplinkBandwidth) {
+  constexpr int kInitChannels = 2;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+
+  // Use low bandwidth to check output switch to 1.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kChannel2To1BandwidthBps);
+  CheckDecision(controller.get(), metrics, 1);
+}
+
+TEST(ChannelControllerTest, Maintain1ChannelOnMediumUplinkBandwidth) {
+  constexpr int kInitChannels = 1;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+
+  // Use between-thresholds bandwidth to check output remains at 1.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kMediumBandwidthBps);
+  CheckDecision(controller.get(), metrics, 1);
+}
+
+TEST(ChannelControllerTest, Maintain2ChannelsOnMediumUplinkBandwidth) {
+  constexpr int kInitChannels = 2;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+
+  // Use between-thresholds bandwidth to check output remains at 2.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kMediumBandwidthBps);
+  CheckDecision(controller.get(), metrics, 2);
+}
+
+TEST(ChannelControllerTest, CheckBehaviorOnChangingUplinkBandwidth) {
+  constexpr int kInitChannels = 1;
+  auto controller = CreateChannelController(kInitChannels);
+  Controller::NetworkMetrics metrics;
+
+  // Use between-thresholds bandwidth to check output remains at 1.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kMediumBandwidthBps);
+  CheckDecision(controller.get(), metrics, 1);
+
+  // Use high bandwidth to check output switch to 2.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kChannel1To2BandwidthBps);
+  CheckDecision(controller.get(), metrics, 2);
+
+  // Use between-thresholds bandwidth to check output remains at 2.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kMediumBandwidthBps);
+  CheckDecision(controller.get(), metrics, 2);
+
+  // Use low bandwidth to check output switch to 1.
+  metrics.uplink_bandwidth_bps = rtc::Optional<int>(kChannel2To1BandwidthBps);
+  CheckDecision(controller.get(), metrics, 1);
+}
+
+}  // namespace webrtc