1 files changed, 125 insertions, 0 deletions
diff --git a/webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.cc b/webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.cc
new file mode 100644
index 0000000..2c987f9
--- /dev/null
+++ b/webrtc/modules/audio_processing/aec3/echo_path_delay_estimator.cc
@@ -0,0 +1,125 @@
+/*
+ *  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 "modules/audio_processing/aec3/echo_path_delay_estimator.h"
+
+#include <array>
+
+#include "api/audio/echo_canceller3_config.h"
+#include "modules/audio_processing/aec3/aec3_common.h"
+#include "modules/audio_processing/aec3/downsampled_render_buffer.h"
+#include "modules/audio_processing/logging/apm_data_dumper.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+EchoPathDelayEstimator::EchoPathDelayEstimator(
+    ApmDataDumper* data_dumper,
+    const EchoCanceller3Config& config,
+    size_t num_capture_channels)
+    : data_dumper_(data_dumper),
+      down_sampling_factor_(config.delay.down_sampling_factor),
+      sub_block_size_(down_sampling_factor_ != 0
+                          ? kBlockSize / down_sampling_factor_
+                          : kBlockSize),
+      capture_mixer_(num_capture_channels,
+                     config.delay.capture_alignment_mixing),
+      capture_decimator_(down_sampling_factor_),
+      matched_filter_(
+          data_dumper_,
+          DetectOptimization(),
+          sub_block_size_,
+          kMatchedFilterWindowSizeSubBlocks,
+          config.delay.num_filters,
+          kMatchedFilterAlignmentShiftSizeSubBlocks,
+          config.delay.down_sampling_factor == 8
+              ? config.render_levels.poor_excitation_render_limit_ds8
+              : config.render_levels.poor_excitation_render_limit,
+          config.delay.delay_estimate_smoothing,
+          config.delay.delay_candidate_detection_threshold),
+      matched_filter_lag_aggregator_(data_dumper_,
+                                     matched_filter_.GetMaxFilterLag(),
+                                     config.delay.delay_selection_thresholds) {
+  RTC_DCHECK(data_dumper);
+  RTC_DCHECK(down_sampling_factor_ > 0);
+}
+
+EchoPathDelayEstimator::~EchoPathDelayEstimator() = default;
+
+void EchoPathDelayEstimator::Reset(bool reset_delay_confidence) {
+  Reset(true, reset_delay_confidence);
+}
+
+absl::optional<DelayEstimate> EchoPathDelayEstimator::EstimateDelay(
+    const DownsampledRenderBuffer& render_buffer,
+    const std::vector<std::vector<float>>& capture) {
+  RTC_DCHECK_EQ(kBlockSize, capture[0].size());
+
+  std::array<float, kBlockSize> downsampled_capture_data;
+  rtc::ArrayView<float> downsampled_capture(downsampled_capture_data.data(),
+                                            sub_block_size_);
+
+  std::array<float, kBlockSize> downmixed_capture;
+  capture_mixer_.ProduceOutput(capture, downmixed_capture);
+  capture_decimator_.Decimate(downmixed_capture, downsampled_capture);
+  data_dumper_->DumpWav("aec3_capture_decimator_output",
+                        downsampled_capture.size(), downsampled_capture.data(),
+                        16000 / down_sampling_factor_, 1);
+  matched_filter_.Update(render_buffer, downsampled_capture);
+
+  absl::optional<DelayEstimate> aggregated_matched_filter_lag =
+      matched_filter_lag_aggregator_.Aggregate(
+          matched_filter_.GetLagEstimates());
+
+  // Run clockdrift detection.
+  if (aggregated_matched_filter_lag &&
+      (*aggregated_matched_filter_lag).quality ==
+          DelayEstimate::Quality::kRefined)
+    clockdrift_detector_.Update((*aggregated_matched_filter_lag).delay);
+
+  // TODO(peah): Move this logging outside of this class once EchoCanceller3
+  // development is done.
+  data_dumper_->DumpRaw(
+      "aec3_echo_path_delay_estimator_delay",
+      aggregated_matched_filter_lag
+          ? static_cast<int>(aggregated_matched_filter_lag->delay *
+                             down_sampling_factor_)
+          : -1);
+
+  // Return the detected delay in samples as the aggregated matched filter lag
+  // compensated by the down sampling factor for the signal being correlated.
+  if (aggregated_matched_filter_lag) {
+    aggregated_matched_filter_lag->delay *= down_sampling_factor_;
+  }
+
+  if (old_aggregated_lag_ && aggregated_matched_filter_lag &&
+      old_aggregated_lag_->delay == aggregated_matched_filter_lag->delay) {
+    ++consistent_estimate_counter_;
+  } else {
+    consistent_estimate_counter_ = 0;
+  }
+  old_aggregated_lag_ = aggregated_matched_filter_lag;
+  constexpr size_t kNumBlocksPerSecondBy2 = kNumBlocksPerSecond / 2;
+  if (consistent_estimate_counter_ > kNumBlocksPerSecondBy2) {
+    Reset(false, false);
+  }
+
+  return aggregated_matched_filter_lag;
+}
+
+void EchoPathDelayEstimator::Reset(bool reset_lag_aggregator,
+                                   bool reset_delay_confidence) {
+  if (reset_lag_aggregator) {
+    matched_filter_lag_aggregator_.Reset(reset_delay_confidence);
+  }
+  matched_filter_.Reset();
+  old_aggregated_lag_ = absl::nullopt;
+  consistent_estimate_counter_ = 0;
+}
+}  // namespace webrtc