Adding full initial version of delay estimation functionality in echo canceller 3

webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.cc

 /*
  *  Copyright (c) 2017 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.
  */
 #include "webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.h"
 
-#include "webrtc/base/checks.h"

[hlundin-webrtc, 2017/02/01 08:30:02]

You are still using checks. Don't delete this.

[peah-webrtc, 2017/02/02 14:04:47]

Done.

+#include <algorithm>
+
 #include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
-#include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
+#include "webrtc/modules/audio_processing/include/audio_processing.h"
 
 namespace webrtc {
 
-// TODO(peah): Add functionality.
+namespace {
+
+constexpr size_t kNumCorrelatorAlignmentShifts = 3;
+constexpr size_t kCorrelatorWindowSizeSubBlocks = 32;
+constexpr size_t kCorrelatorAlignmentShiftSizeSubBlocks =
+    kCorrelatorWindowSizeSubBlocks * 3 / 4;
+
+}  // namespace
+
 EchoPathDelayEstimator::EchoPathDelayEstimator(ApmDataDumper* data_dumper,
-                                               int sample_rate_hz) {
+                                               int sample_rate_hz)
+    : data_dumper_(data_dumper),
+      render_down_sampler_(sample_rate_hz),
+      capture_down_sampler_(sample_rate_hz),
+      down_sampling_factor_(capture_down_sampler_.GetDownSamplingFactor()),

[hlundin-webrtc, 2017/02/01 08:30:02]

Can't you call capture_down_sampler_.GetDownSamplingFactor() when needed instead
of caching it in a member variable? Redundancy leads to discrepancy... :)

But, if the plan is to move the below logging outside of this class, then you'll
probably need a getter method for the downsampling factor. I would still argue
that the getter should just ask the capture_down_sampler_.

[peah-webrtc, 2017/02/02 14:04:47]

I refactored it a bit. PTAL

+      correlator_(data_dumper_,
+                  kCorrelatorWindowSizeSubBlocks,
+                  kNumCorrelatorAlignmentShifts,
+                  kCorrelatorAlignmentShiftSizeSubBlocks),
+      correlator_lag_aggregator_(data_dumper_, correlator_.NumLagEstimates()) {
   RTC_DCHECK(data_dumper);
-  RTC_DCHECK(sample_rate_hz == 8000 || sample_rate_hz == 16000 ||
-             sample_rate_hz == 32000 || sample_rate_hz == 48000);
+  RTC_DCHECK(ValidFullBandRate(sample_rate_hz));
 }
 
 EchoPathDelayEstimator::~EchoPathDelayEstimator() = default;
 
-// TODO(peah): Add functionality.
 rtc::Optional<size_t> EchoPathDelayEstimator::EstimateDelay(
     rtc::ArrayView<const float> render,
     rtc::ArrayView<const float> capture) {
-  RTC_DCHECK_EQ(render.size(), kBlockSize);
-  RTC_DCHECK_EQ(capture.size(), kBlockSize);
-  return rtc::Optional<size_t>();
+  RTC_DCHECK_EQ(kBlockSize, capture.size());
+  RTC_DCHECK_EQ(render.size(), capture.size());
+
+  float downsampled_render[kSubBlockSize];
+  float downsampled_capture[kSubBlockSize];
+
+  render_down_sampler_.DownSample(render, downsampled_render);
+  capture_down_sampler_.DownSample(capture, downsampled_capture);
+
+  correlator_.Update(downsampled_render, downsampled_capture);
+
+  rtc::Optional<size_t> aggregated_correlator_lag =
+      correlator_lag_aggregator_.Aggregate(correlator_.GetLagEstimates());
+
+  // TODO(peah): Move this logging outside of this class once EchoCanceller3
+  // development is done.
+  data_dumper_->DumpRaw(
+      "aec3_echo_path_delay_estimator_delay",
+      aggregated_correlator_lag
+          ? static_cast<int>(*aggregated_correlator_lag * down_sampling_factor_)
+          : -1);
+
+  // Return the detected delay in samples as the aggregated correlator lag
+  // compensated by the down sampling factor for the signal being correlated.
+  return aggregated_correlator_lag
+             ? rtc::Optional<size_t>(*aggregated_correlator_lag *
+                                     down_sampling_factor_)
+             : rtc::Optional<size_t>();
 }
 
 }  // namespace webrtc