Major updates to the echo removal functionality in AEC3

webrtc/modules/audio_processing/aec3/aec3_common.h

 /*
  *  Copyright (c) 2016 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_
 
 #include <stddef.h>
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 #ifdef _MSC_VER /* visual c++ */
 #define ALIGN16_BEG __declspec(align(16))
 #define ALIGN16_END
 #else /* gcc or icc */
 #define ALIGN16_BEG
 #define ALIGN16_END __attribute__((aligned(16)))
 #endif
 
 enum class Aec3Optimization { kNone, kSse2 };
 
-constexpr int kMetricsReportingIntervalBlocks = 10 * 250;
+constexpr int kNumBlocksPerSecond = 250;
+
+constexpr int kMetricsReportingIntervalBlocks = 10 * kNumBlocksPerSecond;
 constexpr int kMetricsComputationBlocks = 9;
 constexpr int kMetricsCollectionBlocks =
     kMetricsReportingIntervalBlocks - kMetricsComputationBlocks;
 
 constexpr int kAdaptiveFilterLength = 12;
+constexpr int kResidualEchoPowerRenderWindowSize = 30;
 
 constexpr size_t kFftLengthBy2 = 64;
 constexpr size_t kFftLengthBy2Plus1 = kFftLengthBy2 + 1;
 constexpr size_t kFftLengthBy2Minus1 = kFftLengthBy2 - 1;
 constexpr size_t kFftLength = 2 * kFftLengthBy2;
 
 constexpr size_t kMaxNumBands = 3;
 constexpr size_t kSubFrameLength = 80;
 
 constexpr size_t kBlockSize = kFftLengthBy2;
 constexpr size_t kExtendedBlockSize = 2 * kFftLengthBy2;
 constexpr size_t kSubBlockSize = 16;
 
 constexpr size_t kNumMatchedFilters = 4;
 constexpr size_t kMatchedFilterWindowSizeSubBlocks = 32;
 constexpr size_t kMatchedFilterAlignmentShiftSizeSubBlocks =
     kMatchedFilterWindowSizeSubBlocks * 3 / 4;
 constexpr size_t kDownsampledRenderBufferSize =
     kSubBlockSize *
     (kMatchedFilterAlignmentShiftSizeSubBlocks * kNumMatchedFilters +
      kMatchedFilterWindowSizeSubBlocks +
      1);
 
+constexpr float kFixedEchoPathGain = 100;
+
 constexpr size_t kRenderDelayBufferSize =
     (3 * kDownsampledRenderBufferSize) / (4 * kSubBlockSize);
 
 constexpr size_t kMaxApiCallsJitterBlocks = 10;
 constexpr size_t kRenderTransferQueueSize = kMaxApiCallsJitterBlocks / 2;
+static_assert(2 * kRenderTransferQueueSize >= kMaxApiCallsJitterBlocks,
+              "Requirement to ensure buffer overflow detection");
 
 constexpr size_t NumBandsForRate(int sample_rate_hz) {
   return static_cast<size_t>(sample_rate_hz == 8000 ? 1
                                                     : sample_rate_hz / 16000);
 }
 constexpr int LowestBandRate(int sample_rate_hz) {
   return sample_rate_hz == 8000 ? sample_rate_hz : 16000;
 }
 
 constexpr bool ValidFullBandRate(int sample_rate_hz) {
@@ skipping 24 matching lines @@
 static_assert(ValidFullBandRate(32000),
               "Test that 32 kHz is a valid sample rate");
 static_assert(ValidFullBandRate(48000),
               "Test that 48 kHz is a valid sample rate");
 static_assert(!ValidFullBandRate(8001),
               "Test that 8001 Hz is not a valid sample rate");
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_