Adding fraction of filter divergence in AEC metrics.

webrtc/modules/audio_processing/utility/block_fraction_calculator.h

+/*
+ *  Copyright 2016 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_UTILITY_BLOCK_FRACTION_CALCULATOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_BLOCK_FRACTION_CALCULATOR_H_
+
+#include <stddef.h>
+
+#include "webrtc/base/constructormagic.h"
+
+namespace webrtc {
+
+// BlockFractionCalculator calculates the fraction of the occurrence of an event
+// in a block. The fraction is updated at the end of every block.
+class BlockFractionCalculator {

[peah-webrtc, 2016/04/06 11:01:10]

Please make this local toaec_core.cc instead.

[peah-webrtc, 2016/04/06 11:01:10]

I think it is better if you name the class in a more specific and less general
manner as it is only used in one place right now. Please change the name to what
is used for, i.e. something along the line of DivergentFilterFraction.

[minyue-webrtc, 2016/04/06 13:35:37]

ok

+ public:
+  explicit BlockFractionCalculator(size_t block_length);
+
+  // Reset.
+  void Reset();
+
+  // Add one observation. |occurred| is true if the event of interest happened,
+  // false otherwise.
+  void AddObservation(bool occurred);
+
+  // Return the latest fraction.
+  float GetLatestFraction() const;
+
+ private:
+  // Clear all values added.
+  void Clear();
+
+  const size_t block_length_;
+  size_t count_;
+  size_t occurrence_;
+  float fraction_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(BlockFractionCalculator);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_BLOCK_FRACTION_CALCULATOR_H_