Fine tune the IntelligibilityEnhancer

webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc

 /*
  *  Copyright (c) 2014 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 13 matching lines @@
 
 namespace {
 
 const size_t kErbResolution = 2;
 const int kWindowSizeMs = 16;
 const int kChunkSizeMs = 10;  // Size provided by APM.
 const float kClipFreqKhz = 0.2f;
 const float kKbdAlpha = 1.5f;
 const float kLambdaBot = -1.f;      // Extreme values in bisection
 const float kLambdaTop = -1e-5f;      // search for lamda.
-const float kVoiceProbabilityThreshold = 0.02f;
+const float kVoiceProbabilityThreshold = 0.5f;
 // Number of chunks after voice activity which is still considered speech.
-const size_t kSpeechOffsetDelay = 80;
-const float kDecayRate = 0.994f;              // Power estimation decay rate.
-const float kMaxRelativeGainChange = 0.006f;
+const size_t kSpeechOffsetDelay = 10;
+const float kDecayRate = 0.995f;              // Power estimation decay rate.
+const float kMaxRelativeGainChange = 0.005f;
 const float kRho = 0.0004f;  // Default production and interpretation SNR.
 const float kPowerNormalizationFactor = 1.f / (1 << 30);
 const float kMaxActiveSNR = 128.f;  // 21dB
 const float kMinInactiveSNR = 32.f;  // 15dB
 const size_t kGainUpdatePeriod = 10u;
 
 // Returns dot product of vectors |a| and |b| with size |length|.
 float DotProduct(const float* a, const float* b, size_t length) {
   float ret = 0.f;
   for (size_t i = 0; i < length; ++i) {
@@ skipping 295 matching lines @@
   vad_.ProcessChunk(audio_s16_.data(), chunk_length_, sample_rate_hz_);
   if (vad_.last_voice_probability() > kVoiceProbabilityThreshold) {
     chunks_since_voice_ = 0;
   } else if (chunks_since_voice_ < kSpeechOffsetDelay) {
     ++chunks_since_voice_;
   }
   return chunks_since_voice_ < kSpeechOffsetDelay;
 }
 
 }  // namespace webrtc