1 /* 2 * Copyright (c) 2011 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 /* 12 * This header file includes the description of the internal VAD call 13 * WebRtcVad_GaussianProbability. 14 */ 15 16 #ifndef WEBRTC_COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ 17 #define WEBRTC_COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ 18 19 #include "typedefs.h" 20 #include "vad_core.h" 21 22 // TODO(bjornv): Move local functions to vad_filterbank.c and make static. 23 /**************************************************************************** 24 * WebRtcVad_HpOutput(...) 25 * 26 * This function removes DC from the lowest frequency band 27 * 28 * Input: 29 * - in_vector : Samples in the frequency interval 0 - 250 Hz 30 * - in_vector_length : Length of input and output vector 31 * - filter_state : Current state of the filter 32 * 33 * Output: 34 * - out_vector : Samples in the frequency interval 80 - 250 Hz 35 * - filter_state : Updated state of the filter 36 * 37 */ 38 void WebRtcVad_HpOutput(int16_t* in_vector, 39 int in_vector_length, 40 int16_t* filter_state, 41 int16_t* out_vector); 42 43 /**************************************************************************** 44 * WebRtcVad_Allpass(...) 45 * 46 * This function is used when before splitting a speech file into 47 * different frequency bands 48 * 49 * Note! Do NOT let the arrays in_vector and out_vector correspond to the same address. 50 * 51 * Input: 52 * - in_vector : (Q0) 53 * - filter_coefficients : (Q15) 54 * - vector_length : Length of input and output vector 55 * - filter_state : Current state of the filter (Q(-1)) 56 * 57 * Output: 58 * - out_vector : Output speech signal (Q(-1)) 59 * - filter_state : Updated state of the filter (Q(-1)) 60 * 61 */ 62 void WebRtcVad_Allpass(int16_t* in_vector, 63 int16_t filter_coefficients, 64 int vector_length, 65 int16_t* filter_state, 66 int16_t* outw16); 67 68 /**************************************************************************** 69 * WebRtcVad_SplitFilter(...) 70 * 71 * This function is used when before splitting a speech file into 72 * different frequency bands 73 * 74 * Input: 75 * - in_vector : Input signal to be split into two frequency bands. 76 * - upper_state : Current state of the upper filter 77 * - lower_state : Current state of the lower filter 78 * - in_vector_length : Length of input vector 79 * 80 * Output: 81 * - out_vector_hp : Upper half of the spectrum 82 * - out_vector_lp : Lower half of the spectrum 83 * - upper_state : Updated state of the upper filter 84 * - lower_state : Updated state of the lower filter 85 * 86 */ 87 void WebRtcVad_SplitFilter(int16_t* in_vector, 88 int in_vector_length, 89 int16_t* upper_state, 90 int16_t* lower_state, 91 int16_t* out_vector_hp, 92 int16_t* out_vector_lp); 93 94 /**************************************************************************** 95 * WebRtcVad_get_features(...) 96 * 97 * This function is used to get the logarithm of the power of each of the 98 * 6 frequency bands used by the VAD: 99 * 80 Hz - 250 Hz 100 * 250 Hz - 500 Hz 101 * 500 Hz - 1000 Hz 102 * 1000 Hz - 2000 Hz 103 * 2000 Hz - 3000 Hz 104 * 3000 Hz - 4000 Hz 105 * 106 * Input: 107 * - inst : Pointer to VAD instance 108 * - in_vector : Input speech signal 109 * - frame_size : Frame size, in number of samples 110 * 111 * Output: 112 * - out_vector : 10*log10(power in each freq. band), Q4 113 * 114 * Return: total power in the signal (NOTE! This value is not exact since it 115 * is only used in a comparison. 116 */ 117 int16_t WebRtcVad_get_features(VadInstT* inst, 118 int16_t* in_vector, 119 int frame_size, 120 int16_t* out_vector); 121 122 /**************************************************************************** 123 * WebRtcVad_LogOfEnergy(...) 124 * 125 * This function is used to get the logarithm of the power of one frequency band. 126 * 127 * Input: 128 * - vector : Input speech samples for one frequency band 129 * - offset : Offset value for the current frequency band 130 * - vector_length : Length of input vector 131 * 132 * Output: 133 * - log_energy : 10*log10(energy); 134 * - power : Update total power in speech frame. NOTE! This value 135 * is not exact since it is only used in a comparison. 136 * 137 */ 138 void WebRtcVad_LogOfEnergy(int16_t* vector, 139 int vector_length, 140 int16_t offset, 141 int16_t* power, 142 int16_t* log_energy); 143 144 #endif // WEBRTC_COMMON_AUDIO_VAD_VAD_FILTERBANK_H_ 145
