Calculating ERLE in AEC more properly.

webrtc/modules/audio_processing/aec/aec_core.c

 /*
  *  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 680 matching lines @@
       // Upper mean
       if (dtmp > aec->aNlp.average) {
         aec->aNlp.hicounter++;
         aec->aNlp.hisum += dtmp;
         aec->aNlp.himean = aec->aNlp.hisum / aec->aNlp.hicounter;
       }
 
       // 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;
       aec->erle.instant = dtmp;
       if (dtmp > aec->erle.max) {
         aec->erle.max = dtmp;
       }
 
       if (dtmp < aec->erle.min) {
         aec->erle.min = dtmp;
@@ skipping 419 matching lines @@
   }
 
   WebRtcAec_OverdriveAndSuppress(aec, hNl, hNlFb, efw);
 
   // Add comfort noise.
   WebRtcAec_ComfortNoise(aec, efw, comfortNoiseHband, aec->noisePow, hNl);
 
   // 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] +
                  aec->outBuf[i] * WebRtcAec_sqrtHanning[PART_LEN - i]);
 
     // Saturate output to keep it in the allowed range.
     output[i] = WEBRTC_SPL_SAT(
         WEBRTC_SPL_WORD16_MAX, output[i], WEBRTC_SPL_WORD16_MIN);
   }
   memcpy(aec->outBuf, &fft[PART_LEN], PART_LEN * sizeof(aec->outBuf[0]));
@@ skipping 211 matching lines @@
 
   if (aec->metricsMode == 1) {
     UpdateLevel(&aec->linoutlevel,
                 CalculatePower(echo_subtractor_output, PART_LEN));
   }
 
   // Perform echo suppression.
   EchoSuppression(aec, farend_ptr, echo_subtractor_output, output, outputH_ptr);
 
   if (aec->metricsMode == 1) {
+    UpdateLevel(&aec->nlpoutlevel, CalculatePower(output, PART_LEN));
     UpdateMetrics(aec);
   }
 
   // Store the output block.
   WebRtc_WriteBuffer(aec->outFrBuf, output, PART_LEN);
   // For high bands
   for (i = 0; i < aec->num_bands - 1; ++i) {
     WebRtc_WriteBuffer(aec->outFrBufH[i], outputH[i], PART_LEN);
   }
 
@@ skipping 519 matching lines @@
 int WebRtcAec_extended_filter_enabled(AecCore* self) {
   return self->extended_filter_enabled;
 }
 
 int WebRtcAec_system_delay(AecCore* self) { return self->system_delay; }
 
 void WebRtcAec_SetSystemDelay(AecCore* self, int delay) {
   assert(delay >= 0);
   self->system_delay = delay;
 }