Some minor (bitexact) AEC echo suppressor refactoring (#2)

webrtc/modules/audio_processing/aec/aec_core_neon.c

 /*
  *  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 492 matching lines @@
 //  - se  : residual echo
 //  - sx  : far-end
 //  - sde : cross-PSD of near-end and residual echo
 //  - sxd : cross-PSD of near-end and far-end
 //
 // In addition to updating the PSDs, also the filter diverge state is determined
 // upon actions are taken.
 static void SmoothedPSD(AecCore* aec,
                         float efw[2][PART_LEN1],
                         float dfw[2][PART_LEN1],
-                        float xfw[2][PART_LEN1]) {
+                        float xfw[2][PART_LEN1],
+                        int* extreme_filter_divergence) {
   // Power estimate smoothing coefficients.
   const float* ptrGCoh = aec->extended_filter_enabled
       ? WebRtcAec_kExtendedSmoothingCoefficients[aec->mult - 1]
       : WebRtcAec_kNormalSmoothingCoefficients[aec->mult - 1];
   int i;
   float sdSum = 0, seSum = 0;
   const float32x4_t vec_15 =  vdupq_n_f32(WebRtcAec_kMinFarendPSD);
   float32x4_t vec_sdSum = vdupq_n_f32(0.0f);
   float32x4_t vec_seSum = vdupq_n_f32(0.0f);
 
@@ skipping 95 matching lines @@
         ptrGCoh[0] * aec->sxd[i][0] +
         ptrGCoh[1] * (dfw[0][i] * xfw[0][i] + dfw[1][i] * xfw[1][i]);
     aec->sxd[i][1] =
         ptrGCoh[0] * aec->sxd[i][1] +
         ptrGCoh[1] * (dfw[0][i] * xfw[1][i] - dfw[1][i] * xfw[0][i]);
 
     sdSum += aec->sd[i];
     seSum += aec->se[i];
   }
 
-  // Divergent filter safeguard.
+  // Divergent filter safeguard update.
   aec->divergeState = (aec->divergeState ? 1.05f : 1.0f) * seSum > sdSum;
 
-  if (aec->divergeState)
-    memcpy(efw, dfw, sizeof(efw[0][0]) * 2 * PART_LEN1);
-
-  // Reset if error is significantly larger than nearend (13 dB).
-  if (!aec->extended_filter_enabled && seSum > (19.95f * sdSum))
-    memset(aec->wfBuf, 0, sizeof(aec->wfBuf));
+  // Signal extreme filter divergence if the error is significantly larger
+  // than the nearend (13 dB).
+  *extreme_filter_divergence = (seSum > (19.95f * sdSum));
 }
 
 // Window time domain data to be used by the fft.
 static void WindowDataNEON(float* x_windowed, const float* x) {
   int i;
   for (i = 0; i < PART_LEN; i += 4) {
     const float32x4_t vec_Buf1 = vld1q_f32(&x[i]);
     const float32x4_t vec_Buf2 = vld1q_f32(&x[PART_LEN + i]);
     const float32x4_t vec_sqrtHanning = vld1q_f32(&WebRtcAec_sqrtHanning[i]);
     // A B C D
@@ skipping 25 matching lines @@
   data_complex[0][0] = data[0];
   data_complex[0][PART_LEN] = data[1];
 }
 
 static void SubbandCoherenceNEON(AecCore* aec,
                                  float efw[2][PART_LEN1],
                                  float dfw[2][PART_LEN1],
                                  float xfw[2][PART_LEN1],
                                  float* fft,
                                  float* cohde,
-                                 float* cohxd) {
+                                 float* cohxd,
+                                 int* extreme_filter_divergence) {
   int i;
 
-  SmoothedPSD(aec, efw, dfw, xfw);
+  SmoothedPSD(aec, efw, dfw, xfw, extreme_filter_divergence);
 
   {
     const float32x4_t vec_1eminus10 =  vdupq_n_f32(1e-10f);
 
     // Subband coherence
     for (i = 0; i + 3 < PART_LEN1; i += 4) {
       const float32x4_t vec_sd = vld1q_f32(&aec->sd[i]);
       const float32x4_t vec_se = vld1q_f32(&aec->se[i]);
       const float32x4_t vec_sx = vld1q_f32(&aec->sx[i]);
       const float32x4_t vec_sdse = vmlaq_f32(vec_1eminus10, vec_sd, vec_se);
@@ skipping 25 matching lines @@
 void WebRtcAec_InitAec_neon(void) {
   WebRtcAec_FilterFar = FilterFarNEON;
   WebRtcAec_ScaleErrorSignal = ScaleErrorSignalNEON;
   WebRtcAec_FilterAdaptation = FilterAdaptationNEON;
   WebRtcAec_OverdriveAndSuppress = OverdriveAndSuppressNEON;
   WebRtcAec_SubbandCoherence = SubbandCoherenceNEON;
   WebRtcAec_StoreAsComplex = StoreAsComplexNEON;
   WebRtcAec_PartitionDelay = PartitionDelayNEON;
   WebRtcAec_WindowData = WindowDataNEON;
 }