Move total audio energy and duration tracking to AudioLevel and protect with existing critial secti…

webrtc/voice_engine/audio_level.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 30 matching lines @@
 }
 
 void AudioLevel::Clear() {
   rtc::CritScope cs(&crit_sect_);
   abs_max_ = 0;
   count_ = 0;
   current_level_ = 0;
   current_level_full_range_ = 0;
 }
 
-void AudioLevel::ComputeLevel(const AudioFrame& audioFrame) {
+double AudioLevel::TotalEnergy() const {
+  rtc::CritScope cs(&crit_sect_);
+  return total_energy_;
+}
+
+double AudioLevel::TotalDuration() const {
+  rtc::CritScope cs(&crit_sect_);
+  return total_duration_;
+}
+
+void AudioLevel::ComputeLevel(const AudioFrame& audioFrame, double duration) {
   // Check speech level (works for 2 channels as well)
   int16_t abs_value = audioFrame.muted() ? 0 :
       WebRtcSpl_MaxAbsValueW16(
           audioFrame.data(),
           audioFrame.samples_per_channel_ * audioFrame.num_channels_);
 
   // Protect member access using a lock since this method is called on a
   // dedicated audio thread in the RecordedDataIsAvailable() callback.
   rtc::CritScope cs(&crit_sect_);
 
@@ skipping 14 matching lines @@
     // Make it less likely that the bar stays at position 0. I.e. only if it's
     // in the range 0-250 (instead of 0-1000)
     if ((position == 0) && (abs_max_ > 250)) {
       position = 1;
     }
     current_level_ = kPermutation[position];
 
     // Decay the absolute maximum (divide by 4)
     abs_max_ >>= 2;
   }
+
+  // See the description for "totalAudioEnergy" in the WebRTC stats spec
+  // (https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamtrackstats-totalaudioenergy)
+  // for an explanation of these formulas. In short, we need a value that can
+  // be used to compute RMS audio levels over different time intervals, by
+  // taking the difference between the results from two getStats calls. To do
+  // this, the value needs to be of units "squared sample value * time".
+  double additional_energy =
+      static_cast<double>(current_level_full_range_) / INT16_MAX;
+  additional_energy *= additional_energy;
+  total_energy_ += additional_energy * duration;
+  total_duration_ += duration;
 }
 
 }  // namespace voe
 }  // namespace webrtc