TWCC-PLR -based FecController doesn’t need smoothing

webrtc/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based.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 "webrtc/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based.h"
 
 #include <limits>
 #include <utility>
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 
+namespace {
+// TODO(elad.alon): Subsequent CL experiments with PLR source.
+constexpr bool kUseTwccPlrForAna = false;
+
+class NullSmoothingFilter final : public SmoothingFilter {
+ public:
+  void AddSample(float sample) override {
+    last_sample_ = rtc::Optional<float>(sample);
+  }
+
+  rtc::Optional<float> GetAverage() override { return last_sample_; }
+
+  bool SetTimeConstantMs(int time_constant_ms) override {
+    RTC_NOTREACHED();
+    return false;
+  }
+
+ private:
+  rtc::Optional<float> last_sample_;
+};
+}
+
 FecControllerPlrBased::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) {}
 
@@ skipping 26 matching lines @@
   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);
 }
 
 FecControllerPlrBased::FecControllerPlrBased(const Config& config)
     : FecControllerPlrBased(
           config,
-          std::unique_ptr<SmoothingFilter>(
-              new SmoothingFilterImpl(config.time_constant_ms, config.clock))) {
-}
+          kUseTwccPlrForAna
+              ? std::unique_ptr<NullSmoothingFilter>(new NullSmoothingFilter())
+              : std::unique_ptr<SmoothingFilter>(
+                    new SmoothingFilterImpl(config.time_constant_ms,
+                                            config.clock))) {}
 
 FecControllerPlrBased::~FecControllerPlrBased() = default;
 
 void FecControllerPlrBased::UpdateNetworkMetrics(
     const NetworkMetrics& network_metrics) {
   if (network_metrics.uplink_bandwidth_bps)
     uplink_bandwidth_bps_ = network_metrics.uplink_bandwidth_bps;
   if (network_metrics.uplink_packet_loss_fraction) {
     packet_loss_smoother_->AddSample(
         *network_metrics.uplink_packet_loss_fraction);
@@ skipping 59 matching lines @@
   if (!uplink_bandwidth_bps_)
     return false;
   if (!packet_loss)
     return false;
   return *packet_loss <= GetPacketLossThreshold(*uplink_bandwidth_bps_,
                                                 config_.fec_disabling_threshold,
                                                 fec_disabling_threshold_info_);
 }
 
 }  // namespace webrtc