Correction of the AEC3 underrun behavior and minor other corrections

webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc

Index: webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
diff --git a/webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc b/webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
index b8d7f28df6b402543fdda02d671b2983ddc319d1..f630b25175eb3b22ef2ee3ee6cfa47f256a0434c 100644
--- a/webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
+++ b/webrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
@@ -188,17 +188,6 @@ void ComfortNoiseGenerator::Compute(
     }
   }
 
-  // Limit the noise to a floor of -96 dBFS.

[peah-webrtc, 2017/04/06 13:39:08]

This limit caused the comfort noise in very silent recordings to be too high.
Removing it solves that.

-  constexpr float kNoiseFloor = 440.f;
-  for (auto& n : N2_) {
-    n = std::max(n, kNoiseFloor);
-  }
-  if (N2_initial_) {
-    for (auto& n : *N2_initial_) {
-      n = std::max(n, kNoiseFloor);
-    }
-  }
-
   // Choose N2 estimate to use.
   const std::array<float, kFftLengthBy2Plus1>& N2 =
       N2_initial_ ? *N2_initial_ : N2_;