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/*
* 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/bitrate_controller.h"
#include "rtc_base/numerics/safe_conversions.h"
#include "test/field_trial.h"
#include "test/gtest.h"
namespace webrtc {
namespace audio_network_adaptor {
namespace {
void UpdateNetworkMetrics(
BitrateController* controller,
const absl::optional<int>& target_audio_bitrate_bps,
const absl::optional<size_t>& overhead_bytes_per_packet) {
// 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 (target_audio_bitrate_bps) {
Controller::NetworkMetrics network_metrics;
network_metrics.target_audio_bitrate_bps = target_audio_bitrate_bps;
controller->UpdateNetworkMetrics(network_metrics);
}
if (overhead_bytes_per_packet) {
Controller::NetworkMetrics network_metrics;
network_metrics.overhead_bytes_per_packet = overhead_bytes_per_packet;
controller->UpdateNetworkMetrics(network_metrics);
}
}
void CheckDecision(BitrateController* controller,
const absl::optional<int>& frame_length_ms,
int expected_bitrate_bps) {
AudioEncoderRuntimeConfig config;
config.frame_length_ms = frame_length_ms;
controller->MakeDecision(&config);
EXPECT_EQ(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;
constexpr size_t kOverheadBytesPerPacket = 64;
BitrateController controller(BitrateController::Config(
kInitialBitrateBps, kInitialFrameLengthMs, 0, 0));
UpdateNetworkMetrics(&controller, absl::nullopt, kOverheadBytesPerPacket);
CheckDecision(&controller, kInitialFrameLengthMs * 2, kInitialBitrateBps);
}
TEST(AnaBitrateControllerTest, OutputInitValueWhenOverheadUnknown) {
constexpr int kInitialBitrateBps = 32000;
constexpr int kInitialFrameLengthMs = 20;
constexpr int kTargetBitrateBps = 48000;
BitrateController controller(BitrateController::Config(
kInitialBitrateBps, kInitialFrameLengthMs, 0, 0));
UpdateNetworkMetrics(&controller, kTargetBitrateBps, absl::nullopt);
CheckDecision(&controller, kInitialFrameLengthMs * 2, kInitialBitrateBps);
}
TEST(AnaBitrateControllerTest, ChangeBitrateOnTargetBitrateChanged) {
constexpr int kInitialFrameLengthMs = 20;
BitrateController controller(
BitrateController::Config(32000, kInitialFrameLengthMs, 0, 0));
constexpr int kTargetBitrateBps = 48000;
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kBitrateBps = kTargetBitrateBps - kOverheadBytesPerPacket * 8 *
1000 /
kInitialFrameLengthMs;
// Frame length unchanged, bitrate changes in accordance with
// `metrics.target_audio_bitrate_bps` and `metrics.overhead_bytes_per_packet`.
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, kInitialFrameLengthMs, kBitrateBps);
}
TEST(AnaBitrateControllerTest, UpdateMultipleNetworkMetricsAtOnce) {
// This test is similar to ChangeBitrateOnTargetBitrateChanged. But instead of
// using ::UpdateNetworkMetrics(...), which calls
// BitrateController::UpdateNetworkMetrics(...) multiple times, we
// we call it only once. This is to verify that
// BitrateController::UpdateNetworkMetrics(...) can handle multiple
// network updates at once. This is, however, not a common use case in current
// audio_network_adaptor_impl.cc.
constexpr int kInitialFrameLengthMs = 20;
BitrateController controller(
BitrateController::Config(32000, kInitialFrameLengthMs, 0, 0));
constexpr int kTargetBitrateBps = 48000;
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kBitrateBps = kTargetBitrateBps - kOverheadBytesPerPacket * 8 *
1000 /
kInitialFrameLengthMs;
Controller::NetworkMetrics network_metrics;
network_metrics.target_audio_bitrate_bps = kTargetBitrateBps;
network_metrics.overhead_bytes_per_packet = kOverheadBytesPerPacket;
controller.UpdateNetworkMetrics(network_metrics);
CheckDecision(&controller, kInitialFrameLengthMs, kBitrateBps);
}
TEST(AnaBitrateControllerTest, TreatUnknownFrameLengthAsFrameLengthUnchanged) {
constexpr int kInitialFrameLengthMs = 20;
BitrateController controller(
BitrateController::Config(32000, kInitialFrameLengthMs, 0, 0));
constexpr int kTargetBitrateBps = 48000;
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kBitrateBps = kTargetBitrateBps - kOverheadBytesPerPacket * 8 *
1000 /
kInitialFrameLengthMs;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, absl::nullopt, kBitrateBps);
}
TEST(AnaBitrateControllerTest, IncreaseBitrateOnFrameLengthIncreased) {
constexpr int kInitialFrameLengthMs = 20;
BitrateController controller(
BitrateController::Config(32000, kInitialFrameLengthMs, 0, 0));
constexpr int kTargetBitrateBps = 48000;
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kBitrateBps = kTargetBitrateBps - kOverheadBytesPerPacket * 8 *
1000 /
kInitialFrameLengthMs;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, absl::nullopt, kBitrateBps);
constexpr int kFrameLengthMs = 60;
constexpr size_t kPacketOverheadRateDiff =
kOverheadBytesPerPacket * 8 * 1000 / 20 -
kOverheadBytesPerPacket * 8 * 1000 / 60;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, kFrameLengthMs,
kBitrateBps + kPacketOverheadRateDiff);
}
TEST(AnaBitrateControllerTest, DecreaseBitrateOnFrameLengthDecreased) {
constexpr int kInitialFrameLengthMs = 60;
BitrateController controller(
BitrateController::Config(32000, kInitialFrameLengthMs, 0, 0));
constexpr int kTargetBitrateBps = 48000;
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kBitrateBps = kTargetBitrateBps - kOverheadBytesPerPacket * 8 *
1000 /
kInitialFrameLengthMs;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, absl::nullopt, kBitrateBps);
constexpr int kFrameLengthMs = 20;
constexpr size_t kPacketOverheadRateDiff =
kOverheadBytesPerPacket * 8 * 1000 / 20 -
kOverheadBytesPerPacket * 8 * 1000 / 60;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, kFrameLengthMs,
kBitrateBps - kPacketOverheadRateDiff);
}
TEST(AnaBitrateControllerTest, BitrateNeverBecomesNegative) {
BitrateController controller(BitrateController::Config(32000, 20, 0, 0));
constexpr size_t kOverheadBytesPerPacket = 64;
constexpr int kFrameLengthMs = 60;
// Set a target rate smaller than overhead rate, the bitrate is bounded by 0.
constexpr int kTargetBitrateBps =
kOverheadBytesPerPacket * 8 * 1000 / kFrameLengthMs - 1;
UpdateNetworkMetrics(&controller, kTargetBitrateBps, kOverheadBytesPerPacket);
CheckDecision(&controller, kFrameLengthMs, 0);
}
TEST(AnaBitrateControllerTest, CheckBehaviorOnChangingCondition) {
BitrateController controller(BitrateController::Config(32000, 20, 0, 0));
// Start from an arbitrary overall bitrate.
int overall_bitrate = 34567;
size_t overhead_bytes_per_packet = 64;
int frame_length_ms = 20;
int current_bitrate = rtc::checked_cast<int>(
overall_bitrate - overhead_bytes_per_packet * 8 * 1000 / frame_length_ms);
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
// Next: increase overall bitrate.
overall_bitrate += 100;
current_bitrate += 100;
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
// Next: change frame length.
frame_length_ms = 60;
current_bitrate +=
rtc::checked_cast<int>(overhead_bytes_per_packet * 8 * 1000 / 20 -
overhead_bytes_per_packet * 8 * 1000 / 60);
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
// Next: change overhead.
overhead_bytes_per_packet -= 30;
current_bitrate += 30 * 8 * 1000 / frame_length_ms;
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
// Next: change frame length.
frame_length_ms = 20;
current_bitrate -=
rtc::checked_cast<int>(overhead_bytes_per_packet * 8 * 1000 / 20 -
overhead_bytes_per_packet * 8 * 1000 / 60);
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
// Next: decrease overall bitrate and frame length.
overall_bitrate -= 100;
current_bitrate -= 100;
frame_length_ms = 60;
current_bitrate +=
rtc::checked_cast<int>(overhead_bytes_per_packet * 8 * 1000 / 20 -
overhead_bytes_per_packet * 8 * 1000 / 60);
UpdateNetworkMetrics(&controller, overall_bitrate, overhead_bytes_per_packet);
CheckDecision(&controller, frame_length_ms, current_bitrate);
}
} // namespace audio_network_adaptor
} // namespace webrtc
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