Pull the Voice Activity Detector out from the AGC

webrtc/modules/audio_processing/agc/pole_zero_filter.h

-/*
- *  Copyright (c) 2012 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_AGC_POLE_ZERO_FILTER_H_
-#define WEBRTC_MODULES_AUDIO_PROCESSING_AGC_POLE_ZERO_FILTER_H_
-
-#include "webrtc/typedefs.h"
-
-namespace webrtc {
-
-class PoleZeroFilter {
- public:
-  ~PoleZeroFilter() {}
-
-  static PoleZeroFilter* Create(const float* numerator_coefficients,
-                                int order_numerator,
-                                const float* denominator_coefficients,
-                                int order_denominator);
-
-  int Filter(const int16_t* in, int num_input_samples, float* output);
-
- private:
-  PoleZeroFilter(const float* numerator_coefficients,
-                 int order_numerator,
-                 const float* denominator_coefficients,
-                 int order_denominator);
-
-  static const int kMaxFilterOrder = 24;
-
-  int16_t past_input_[kMaxFilterOrder * 2];
-  float past_output_[kMaxFilterOrder * 2];
-
-  float numerator_coefficients_[kMaxFilterOrder + 1];
-  float denominator_coefficients_[kMaxFilterOrder + 1];
-
-  int order_numerator_;
-  int order_denominator_;
-  int highest_order_;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AGC_POLE_ZERO_FILTER_H_