Finalization of the first version of EchoCanceller 3

webrtc/modules/audio_processing/aec3/subtractor.h

+/*
+ *  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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_SUBTRACTOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_SUBTRACTOR_H_
+
+#include <stdio.h>
+#include <algorithm>
+#include <memory>
+#include <vector>
+

[aleloi, 2017/02/13 16:44:51]

stdio, memory not needed, <array> missing.

[peah-webrtc, 2017/02/20 07:37:19]

Done.

+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/adaptive_fir_filter.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_fft.h"
+#include "webrtc/modules/audio_processing/aec3/echo_path_variability.h"
+#include "webrtc/modules/audio_processing/aec3/fft_buffer.h"
+#include "webrtc/modules/audio_processing/aec3/main_filter_update_gain.h"
+#include "webrtc/modules/audio_processing/aec3/shadow_filter_update_gain.h"
+#include "webrtc/modules/audio_processing/aec3/subtractor_output.h"
+#include "webrtc/modules/audio_processing/logging/apm_data_dumper.h"
+#include "webrtc/modules/audio_processing/utility/ooura_fft.h"
+
+namespace webrtc {
+
+// Proves linear echo cancellation functionality
+class Subtractor {
+ public:
+  explicit Subtractor(ApmDataDumper* data_dumper);
+  ~Subtractor();
+
+  // Performs the echo subtraction.
+  void Process(const FftBuffer& render_buffer,
+               const rtc::ArrayView<const float> capture,
+               const RenderSignalAnalyzer& render_signal_analyzer,
+               bool saturation,
+               SubtractorOutput* output);
+
+  // Returns a vector with the number of blocks included in the render buffer
+  // sums.
+  std::vector<size_t> NumBlocksInRenderSums() const;

[aleloi, 2017/02/13 16:44:51]

This could probably be a constexpr function if the return type is changed from
std::vector and the filter length constants are constexpr.

[peah-webrtc, 2017/02/20 07:37:19]

That makes sense. This should be changed, but I prefer to keep that for another
CL.

If the current tuning holds, the shadow and main filters are equally long, which
means that they should be applied and updated jointly. Then this method will be
changed as well.

WDYT?

[aleloi, 2017/02/23 15:16:00]

sgtm

+
+  // Returns the minimum required farend buffer length.
+  size_t MinFarendBufferLength() const {
+    return std::max(kMainFilterLength, kShadowFilterLength);

[aleloi, 2017/02/13 16:44:51]

Can be a constexpr function if the constants are costexpr.

[peah-webrtc, 2017/02/20 07:37:19]

Not fully sure how I can make the constants constexpr. Either way I try, I get
different errors. Do you have any suggestion on how to accomplish that?

[hlundin-webrtc, 2017/02/22 21:17:28]

You will have to make them static constexpr. Then you should be able to  make
the function constexpr too, I believe.

[aleloi, 2017/02/23 15:16:00]

Acknowledged.

+  }
+
+  void HandleEchoPathChange(const EchoPathVariability& echo_path_variability);
+
+  // Returns the block-wise frequency response of the main adaptive filter.
+  const std::vector<std::array<float, kFftLengthBy2Plus1>>&
+  FilterFrequencyResponse() const {
+    return main_filter_.FilterFrequencyResponse();
+  }
+
+ private:
+  const size_t kMainFilterLength = 12;
+  const size_t kShadowFilterLength = 12;

[aleloi, 2017/02/13 16:44:51]

constexpr.

[peah-webrtc, 2017/02/20 07:37:19]

See above.

+
+  const Aec3Fft fft_;
+  ApmDataDumper* data_dumper_;
+  AdaptiveFirFilter main_filter_;
+  AdaptiveFirFilter shadow_filter_;
+  MainFilterUpdateGain G_main_;
+  ShadowFilterUpdateGain G_shadow_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Subtractor);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_SUBTRACTOR_H_