Calculating ERLE in AEC more properly.

webrtc/modules/audio_processing/aec/aec_core.c

Index: webrtc/modules/audio_processing/aec/aec_core.c
diff --git a/webrtc/modules/audio_processing/aec/aec_core.c b/webrtc/modules/audio_processing/aec/aec_core.c
index 18189a0b7c8215a8d4d71b233186028c9a589159..13f58ce32bbd4c1f74b023c036790b9788599207 100644
--- a/webrtc/modules/audio_processing/aec/aec_core.c
+++ b/webrtc/modules/audio_processing/aec/aec_core.c
@@ -698,12 +698,11 @@ static void UpdateMetrics(AecCore* aec) {
       // ERLE
 
       // subtract noise power
-      suppressedEcho = 2 * (aec->nlpoutlevel.averagelevel -
-                            safety * aec->nlpoutlevel.minlevel);
+      suppressedEcho = aec->nlpoutlevel.averagelevel -
+          safety * aec->nlpoutlevel.minlevel;
 
       dtmp = 10 * (float)log10(aec->nearlevel.averagelevel /
-                                   (2 * aec->nlpoutlevel.averagelevel) +
-                               1e-10f);
+          aec->nlpoutlevel.averagelevel + 1e-10f);
       dtmp2 = 10 * (float)log10(echo / suppressedEcho + 1e-10f);
 
       dtmp = dtmp2;
@@ -1143,16 +1142,6 @@ static void EchoSuppression(AecCore* aec,
   // Inverse error fft.
   ScaledInverseFft(efw, fft, 2.0f, 1);
 
-  // TODO(bjornv): Investigate how to take the windowing below into account if
-  // needed.
-  if (aec->metricsMode == 1) {
-    // Note that we have a scaling by two in the time domain |eBuf|.
-    // In addition the time domain signal is windowed before transformation,
-    // losing half the energy on the average. We take care of the first
-    // scaling only in UpdateMetrics().
-    UpdateLevel(&aec->nlpoutlevel, CalculatePower(fft, PART_LEN2));
-  }
-
   // Overlap and add to obtain output.
   for (i = 0; i < PART_LEN; i++) {
     output[i] = (fft[i] * WebRtcAec_sqrtHanning[i] +
@@ -1384,6 +1373,7 @@ static void ProcessBlock(AecCore* aec) {
   EchoSuppression(aec, farend_ptr, echo_subtractor_output, output, outputH_ptr);
 
   if (aec->metricsMode == 1) {
+    UpdateLevel(&aec->nlpoutlevel, CalculatePower(output, PART_LEN));
     UpdateMetrics(aec);
   }