Adding fraction of filter divergence in AEC metrics.

webrtc/modules/audio_processing/aec/aec_core.cc

Index: webrtc/modules/audio_processing/aec/aec_core.cc
diff --git a/webrtc/modules/audio_processing/aec/aec_core.cc b/webrtc/modules/audio_processing/aec/aec_core.cc
index 1b5f03fec4e7a255f25c681218bbb7470ebc0770..7fdf8b62958f33072920c6924ed1a9d4ebcb9f95 100644
--- a/webrtc/modules/audio_processing/aec/aec_core.cc
+++ b/webrtc/modules/audio_processing/aec/aec_core.cc
@@ -50,6 +50,12 @@ static const int subCountLen = 4;
 static const int countLen = 50;
 static const int kDelayMetricsAggregationWindow = 1250;  // 5 seconds at 16 kHz.
 
+// Diverge metric is based on audio level, which gets updated which every

[tlegrand-webrtc, 2016/03/17 12:28:39]

You haven't addressed my comments from Patch Set 1:
Diverge -> Divergence
which every -> every.

[minyue-webrtc, 2016/04/03 21:42:06]

Sorry, I might have missed it. Now it is addressed.

+// |subCountLen + 1| * 10 milliseconds. Diverge metric takes the statistics of
+// |kDivergeMetricAggregationWindow| samples. Current value corresponds to  0.5
+// seconds at 16 kHz.
+static const int kDivergeMetricAggregationWindow = 25;
+
 // Quantities to control H band scaling for SWB input
 static const float cnScaleHband = 0.4f;  // scale for comfort noise in H band.
 // Initial bin for averaging nlp gain in low band
@@ -556,6 +562,8 @@ static void InitMetrics(AecCore* self) {
   InitStats(&self->erle);
   InitStats(&self->aNlp);
   InitStats(&self->rerl);
+
+  self->fraction_filter_divergent->Clear();
 }
 
 static float CalculatePower(const float* in, size_t num_samples) {
@@ -613,6 +621,16 @@ static void UpdateMetrics(AecCore* aec) {
     aec->stateCounter++;
   }
 
+  if (aec->linoutlevel.sfrcounter == 0) {
+    const float level_increase =
+        aec->linoutlevel.framelevel - aec->nearlevel.framelevel;
+    // Level increase should be, in principle, negative, when the filter
+    // does not diverge. Here we allow some margin (0.001 * near end level) and
+    // numerical error (1.0).
+    aec->fraction_filter_divergent->AddSample(level_increase >
+        std::max(0.001 * aec->nearlevel.framelevel, 1.0) ? 1.0 : 0.0);
+  }
+
   if (aec->farlevel.frcounter == 0) {
     if (aec->farlevel.minlevel < noisyPower) {
       actThreshold = actThresholdClean;
@@ -1365,7 +1383,7 @@ static void ProcessBlock(AecCore* aec) {
 
 AecCore* WebRtcAec_CreateAec() {
   int i;
-  AecCore* aec = reinterpret_cast<AecCore*>(malloc(sizeof(AecCore)));
+  AecCore* aec = new AecCore;
   if (!aec) {
     return NULL;
   }
@@ -1429,6 +1447,14 @@ AecCore* WebRtcAec_CreateAec() {
     WebRtcAec_FreeAec(aec);
     return NULL;
   }
+
+  aec->fraction_filter_divergent.reset(
+      new webrtc::MeanCalculator(kDivergeMetricAggregationWindow));

[tlegrand-webrtc, 2016/03/17 12:28:39]

Do you need webrtc:: here? Looks like we are in the webrtc namespace.

[minyue-webrtc, 2016/04/03 21:42:05]

True. the namespace was added recently. now I can remove webrtc::

+  if (aec->fraction_filter_divergent.get() == nullptr) {

[tlegrand-webrtc, 2016/03/17 12:28:39]

Can you explain what happens here?

[minyue-webrtc, 2016/04/03 21:42:06]

This is to check if the memory is allocated correctly. But now I avoid dynamic
memory allocation.

+    WebRtcAec_FreeAec(aec);
+    return NULL;
+  }
+
 #ifdef WEBRTC_ANDROID
   aec->delay_agnostic_enabled = 1;  // DA-AEC enabled by default.
   // DA-AEC assumes the system is causal from the beginning and will self adjust