Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2016 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 WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_BIQUAD_FILTER_H_
      12             : #define WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_BIQUAD_FILTER_H_
      13             : 
      14             : #include <vector>
      15             : 
      16             : #include "webrtc/base/array_view.h"
      17             : #include "webrtc/base/arraysize.h"
      18             : #include "webrtc/base/constructormagic.h"
      19             : 
      20             : namespace webrtc {
      21             : 
      22             : class BiQuadFilter {
      23             :  public:
      24             :   struct BiQuadCoefficients {
      25             :     float b[3];
      26             :     float a[2];
      27             :   };
      28             : 
      29           0 :   BiQuadFilter() = default;
      30             : 
      31           0 :   void Initialize(const BiQuadCoefficients& coefficients) {
      32           0 :     coefficients_ = coefficients;
      33           0 :   }
      34             : 
      35             :   // Produces a filtered output y of the input x. Both x and y need to
      36             :   // have the same length.
      37             :   void Process(rtc::ArrayView<const float> x, rtc::ArrayView<float> y);
      38             : 
      39             :  private:
      40             :   struct BiQuadState {
      41           0 :     BiQuadState() {
      42           0 :       std::fill(b, b + arraysize(b), 0.f);
      43           0 :       std::fill(a, a + arraysize(a), 0.f);
      44           0 :     }
      45             : 
      46             :     float b[2];
      47             :     float a[2];
      48             :   };
      49             : 
      50             :   BiQuadState biquad_state_;
      51             :   BiQuadCoefficients coefficients_;
      52             : 
      53             :   RTC_DISALLOW_COPY_AND_ASSIGN(BiQuadFilter);
      54             : };
      55             : 
      56             : }  // namespace webrtc
      57             : 
      58             : #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_BIQUAD_FILTER_H_