| /* |
| * 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 "webrtc/modules/audio_coding/audio_network_adaptor/fec_controller.h" |
| |
| #include <limits> |
| #include <utility> |
| |
| #include "webrtc/base/checks.h" |
| |
| namespace webrtc { |
| |
| FecController::Config::Threshold::Threshold(int low_bandwidth_bps, |
| float low_bandwidth_packet_loss, |
| int high_bandwidth_bps, |
| float high_bandwidth_packet_loss) |
| : low_bandwidth_bps(low_bandwidth_bps), |
| low_bandwidth_packet_loss(low_bandwidth_packet_loss), |
| high_bandwidth_bps(high_bandwidth_bps), |
| high_bandwidth_packet_loss(high_bandwidth_packet_loss) {} |
| |
| FecController::Config::Config(bool initial_fec_enabled, |
| const Threshold& fec_enabling_threshold, |
| const Threshold& fec_disabling_threshold, |
| int time_constant_ms, |
| const Clock* clock) |
| : initial_fec_enabled(initial_fec_enabled), |
| fec_enabling_threshold(fec_enabling_threshold), |
| fec_disabling_threshold(fec_disabling_threshold), |
| time_constant_ms(time_constant_ms), |
| clock(clock) {} |
| |
| FecController::FecController(const Config& config) |
| : config_(config), |
| fec_enabled_(config.initial_fec_enabled), |
| packet_loss_smoothed_( |
| new SmoothingFilterImpl(config_.time_constant_ms, config_.clock)), |
| fec_enabling_threshold_info_(config_.fec_enabling_threshold), |
| fec_disabling_threshold_info_(config_.fec_disabling_threshold) { |
| RTC_DCHECK_LE(fec_enabling_threshold_info_.slope, 0); |
| RTC_DCHECK_LE(fec_enabling_threshold_info_.slope, 0); |
| RTC_DCHECK_LE( |
| GetPacketLossThreshold(config_.fec_enabling_threshold.low_bandwidth_bps, |
| config_.fec_disabling_threshold, |
| fec_disabling_threshold_info_), |
| config_.fec_enabling_threshold.low_bandwidth_packet_loss); |
| RTC_DCHECK_LE( |
| GetPacketLossThreshold(config_.fec_enabling_threshold.high_bandwidth_bps, |
| config_.fec_disabling_threshold, |
| fec_disabling_threshold_info_), |
| config_.fec_enabling_threshold.high_bandwidth_packet_loss); |
| } |
| |
| FecController::FecController(const Config& config, |
| std::unique_ptr<SmoothingFilter> smoothing_filter) |
| : FecController(config) { |
| packet_loss_smoothed_ = std::move(smoothing_filter); |
| } |
| |
| FecController::~FecController() = default; |
| |
| void FecController::MakeDecision( |
| const NetworkMetrics& metrics, |
| AudioNetworkAdaptor::EncoderRuntimeConfig* config) { |
| RTC_DCHECK(!config->enable_fec); |
| RTC_DCHECK(!config->uplink_packet_loss_fraction); |
| |
| if (metrics.uplink_packet_loss_fraction) |
| packet_loss_smoothed_->AddSample(*metrics.uplink_packet_loss_fraction); |
| |
| fec_enabled_ = fec_enabled_ ? !FecDisablingDecision(metrics) |
| : FecEnablingDecision(metrics); |
| |
| config->enable_fec = rtc::Optional<bool>(fec_enabled_); |
| |
| auto packet_loss_fraction = packet_loss_smoothed_->GetAverage(); |
| config->uplink_packet_loss_fraction = rtc::Optional<float>( |
| packet_loss_fraction ? *packet_loss_fraction : 0.0); |
| } |
| |
| FecController::ThresholdInfo::ThresholdInfo( |
| const Config::Threshold& threshold) { |
| int bandwidth_diff_bps = |
| threshold.high_bandwidth_bps - threshold.low_bandwidth_bps; |
| float packet_loss_diff = threshold.high_bandwidth_packet_loss - |
| threshold.low_bandwidth_packet_loss; |
| slope = bandwidth_diff_bps == 0 ? 0.0 : packet_loss_diff / bandwidth_diff_bps; |
| offset = |
| threshold.low_bandwidth_packet_loss - slope * threshold.low_bandwidth_bps; |
| } |
| |
| float FecController::GetPacketLossThreshold( |
| int bandwidth_bps, |
| const Config::Threshold& threshold, |
| const ThresholdInfo& threshold_info) const { |
| if (bandwidth_bps < threshold.low_bandwidth_bps) |
| return std::numeric_limits<float>::max(); |
| if (bandwidth_bps >= threshold.high_bandwidth_bps) |
| return threshold.high_bandwidth_packet_loss; |
| return threshold_info.offset + threshold_info.slope * bandwidth_bps; |
| } |
| |
| bool FecController::FecEnablingDecision(const NetworkMetrics& metrics) const { |
| if (!metrics.uplink_bandwidth_bps) |
| return false; |
| |
| auto packet_loss = packet_loss_smoothed_->GetAverage(); |
| if (!packet_loss) |
| return false; |
| |
| return *packet_loss >= GetPacketLossThreshold(*metrics.uplink_bandwidth_bps, |
| config_.fec_enabling_threshold, |
| fec_enabling_threshold_info_); |
| } |
| |
| bool FecController::FecDisablingDecision(const NetworkMetrics& metrics) const { |
| if (!metrics.uplink_bandwidth_bps) |
| return false; |
| |
| auto packet_loss = packet_loss_smoothed_->GetAverage(); |
| if (!packet_loss) |
| return false; |
| |
| return *packet_loss <= GetPacketLossThreshold(*metrics.uplink_bandwidth_bps, |
| config_.fec_disabling_threshold, |
| fec_disabling_threshold_info_); |
| } |
| |
| } // namespace webrtc |