Compensate for the IntelligibilityEnhancer processing delay in high bands

webrtc/modules/audio_processing/intelligibility/intelligibility_utils.cc

 /*
  *  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 48 matching lines @@
 GainApplier::~GainApplier() {}
 
 void GainApplier::Apply(const std::complex<float>* in_block,
                         std::complex<float>* out_block) {
   for (size_t i = 0; i < num_freqs_; ++i) {
     current_[i] = UpdateFactor(target_[i], current_[i], relative_change_limit_);
     out_block[i] = sqrtf(fabsf(current_[i])) * in_block[i];
   }
 }
 
+DelayBuffer::DelayBuffer(size_t delay, size_t num_channels)
+    : buffer_(num_channels, std::vector<float>(delay, 0.f)), read_index_(0u) {}
+
+DelayBuffer::~DelayBuffer() {}
+
+void DelayBuffer::Delay(float* const* data, size_t length) {
+  size_t sample_index = read_index_;
+  for (size_t i = 0u; i < buffer_.size(); ++i) {
+    sample_index = read_index_;
+    for (size_t j = 0u; j < length; ++j) {
+      float swap = data[i][j];
+      data[i][j] = buffer_[i][sample_index];
+      buffer_[i][sample_index] = swap;
+      if (++sample_index == buffer_.size()) {
+        sample_index = 0u;
+      }
+    }
+  }
+  read_index_ = sample_index;
+}
+
 }  // namespace intelligibility
 
 }  // namespace webrtc