Moving FFT on farend signal to where it is used in AEC (bit exact).

webrtc/modules/audio_processing/aec/echo_cancellation.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 299 matching lines @@
     farend_ptr = new_farend;
   }
 
   aecpc->farend_started = 1;
   WebRtcAec_SetSystemDelay(
       aecpc->aec, WebRtcAec_system_delay(aecpc->aec) + (int)newNrOfSamples);
 
   // Write the time-domain data to |far_pre_buf|.
   WebRtc_WriteBuffer(aecpc->far_pre_buf, farend_ptr, newNrOfSamples);
 
-  // Transform to frequency domain if we have enough data.
+  // TODO(minyue): reduce to |PART_LEN| samples for each buffering, when
+  // WebRtcAec_BufferFarendPartition() is changed to take |PART_LEN| samples.
   while (WebRtc_available_read(aecpc->far_pre_buf) >= PART_LEN2) {
     // We have enough data to pass to the FFT, hence read PART_LEN2 samples.
     {
       float* ptmp = NULL;
       float tmp[PART_LEN2];
       WebRtc_ReadBuffer(aecpc->far_pre_buf, (void**)&ptmp, tmp, PART_LEN2);
       WebRtcAec_BufferFarendPartition(aecpc->aec, ptmp);
-#ifdef WEBRTC_AEC_DEBUG_DUMP
-      WebRtc_WriteBuffer(
-          WebRtcAec_far_time_buf(aecpc->aec), &ptmp[PART_LEN], 1);
-#endif
     }
 
     // Rewind |far_pre_buf| PART_LEN samples for overlap before continuing.
     WebRtc_MoveReadPtr(aecpc->far_pre_buf, -PART_LEN);
   }
 
   return 0;
 }
 
 int32_t WebRtcAec_Process(void* aecInst,
@@ skipping 554 matching lines @@
     }
   } else {
     self->timeForDelayChange = 0;
   }
   self->lastDelayDiff = delay_difference;
 
   if (self->timeForDelayChange > 25) {
     self->knownDelay = WEBRTC_SPL_MAX((int)self->filtDelay - 256, 0);
   }
 }