gain_change_calculator.h (1346B)
1 /* 2 * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_AUDIO_MIXER_GAIN_CHANGE_CALCULATOR_H_ 12 #define MODULES_AUDIO_MIXER_GAIN_CHANGE_CALCULATOR_H_ 13 14 #include <stdint.h> 15 16 #include "api/array_view.h" 17 18 namespace webrtc { 19 20 class GainChangeCalculator { 21 public: 22 // The 'out' signal is assumed to be produced from 'in' by applying 23 // a smoothly varying gain. This method computes variations of the 24 // gain and handles special cases when the samples are small. 25 float CalculateGainChange(ArrayView<const int16_t> in, 26 ArrayView<const int16_t> out); 27 28 float LatestGain() const; 29 30 private: 31 void CalculateGain(ArrayView<const int16_t> in, 32 ArrayView<const int16_t> out, 33 ArrayView<float> gain); 34 35 float CalculateDifferences(ArrayView<const float> values); 36 float last_value_ = 0.f; 37 float last_reliable_gain_ = 1.0f; 38 }; 39 40 } // namespace webrtc 41 42 #endif // MODULES_AUDIO_MIXER_GAIN_CHANGE_CALCULATOR_H_