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 <array>
+#include <algorithm>
+#include <vector>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_processing/aec3/adaptive_fir_filter.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_common.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:
+  Subtractor(ApmDataDumper* data_dumper, Aec3Optimization optimization);
+  ~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;
+
+  // Returns the minimum required farend buffer length.
+  size_t MinFarendBufferLength() const {
+    return std::max(kMainFilterLength, kShadowFilterLength);
+  }
+
+  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;

[aleloi, 2017/02/22 16:20:31]

Please change to constexpr.

[aleloi, 2017/02/22 16:20:31]

The constant is called 'filter length' here, but 'size_partitions' in the filter
c-tor. I suggest choosing a common name.

[hlundin-webrtc, 2017/02/22 21:17:29]

static constexpr

[peah-webrtc, 2017/02/22 23:51:39]

I cannot get that to work as I get linker errors. I don't get fully clear on why
that happens, some references claim it is a clang bug, and some claims it is due
to the definition of constexpr. I'll keep it as it is for now.

[peah-webrtc, 2017/02/22 23:51:39]

I cannot get that to work as I get linker errors. I don't get fully clear on why
that happens, some references claim it is a clang bug, and some claims it is due
to the definition of constexpr. I'll keep it as it is for now.

[peah-webrtc, 2017/02/22 23:51:40]

Good point!

Done.

[hlundin-webrtc, 2017/02/23 07:42:09]

Keep it as it is now, but I wonder if the reason it won't work is because
std::max takes a reference to its parameters. And, taking a reference to a
static const member won't work, unless it is defined somewhere (to give it an
addressable place in memory).

So, in the .cc file, you will have to add 
static constexpr size_t Subtractor::kMainFilterLength;

Then I believe it should work. See:
http://stackoverflow.com/questions/272900/undefined-reference-to-static-class...
http://stackoverflow.com/questions/185844/initializing-private-static-members

[peah-webrtc, 2017/02/23 11:18:32]

Acknowledged.

+  const size_t kShadowFilterLength = 12;

[aleloi, 2017/02/22 16:20:31]

Same here

[peah-webrtc, 2017/02/22 23:51:40]

Done.

+
+  const Aec3Fft fft_;
+  ApmDataDumper* data_dumper_;
+  const Aec3Optimization optimization_;
+  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_