1 /* 2 * Copyright (c) 2014 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_COMMON_AUDIO_FIR_FILTER_H_ 12 #define WEBRTC_COMMON_AUDIO_FIR_FILTER_H_ 13 14 #include <string.h> 15 16 namespace webrtc { 17 18 // Finite Impulse Response filter using floating-point arithmetic. 19 class FIRFilter { 20 public: 21 // Creates a filter with the given coefficients. All initial state values will 22 // be zeros. 23 // The length of the chunks fed to the filter should never be greater than 24 // |max_input_length|. This is needed because, when vectorizing it is 25 // necessary to concatenate the input after the state, and resizing this array 26 // dynamically is expensive. 27 static FIRFilter* Create(const float* coefficients, 28 size_t coefficients_length, 29 size_t max_input_length); 30 31 virtual ~FIRFilter() {} 32 33 // Filters the |in| data supplied. 34 // |out| must be previously allocated and it must be at least of |length|. 35 virtual void Filter(const float* in, size_t length, float* out) = 0; 36 }; 37 38 } // namespace webrtc 39 40 #endif // WEBRTC_COMMON_AUDIO_FIR_FILTER_H_ 41
