1c55a96383497a772a307b346368133960b02ad03Eric Laurent/* 2c55a96383497a772a307b346368133960b02ad03Eric Laurent * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3c55a96383497a772a307b346368133960b02ad03Eric Laurent * 4c55a96383497a772a307b346368133960b02ad03Eric Laurent * Use of this source code is governed by a BSD-style license 5c55a96383497a772a307b346368133960b02ad03Eric Laurent * that can be found in the LICENSE file in the root of the source 6c55a96383497a772a307b346368133960b02ad03Eric Laurent * tree. An additional intellectual property rights grant can be found 7c55a96383497a772a307b346368133960b02ad03Eric Laurent * in the file PATENTS. All contributing project authors may 8c55a96383497a772a307b346368133960b02ad03Eric Laurent * be found in the AUTHORS file in the root of the source tree. 9c55a96383497a772a307b346368133960b02ad03Eric Laurent */ 10c55a96383497a772a307b346368133960b02ad03Eric Laurent 11c55a96383497a772a307b346368133960b02ad03Eric Laurent#include "vad_sp.h" 12c55a96383497a772a307b346368133960b02ad03Eric Laurent 13c55a96383497a772a307b346368133960b02ad03Eric Laurent#include <assert.h> 14c55a96383497a772a307b346368133960b02ad03Eric Laurent 15c55a96383497a772a307b346368133960b02ad03Eric Laurent#include "signal_processing_library.h" 16c55a96383497a772a307b346368133960b02ad03Eric Laurent#include "typedefs.h" 17c55a96383497a772a307b346368133960b02ad03Eric Laurent#include "vad_defines.h" 18c55a96383497a772a307b346368133960b02ad03Eric Laurent 19c55a96383497a772a307b346368133960b02ad03Eric Laurent// Allpass filter coefficients, upper and lower, in Q13. 20c55a96383497a772a307b346368133960b02ad03Eric Laurent// Upper: 0.64, Lower: 0.17. 21c55a96383497a772a307b346368133960b02ad03Eric Laurentstatic const int16_t kAllPassCoefsQ13[2] = { 5243, 1392 }; // Q13 22c55a96383497a772a307b346368133960b02ad03Eric Laurent 23c55a96383497a772a307b346368133960b02ad03Eric Laurent// TODO(bjornv): Move this function to vad_filterbank.c. 24c55a96383497a772a307b346368133960b02ad03Eric Laurent// Downsampling filter based on splitting filter and allpass functions. 25c55a96383497a772a307b346368133960b02ad03Eric Laurentvoid WebRtcVad_Downsampling(int16_t* signal_in, 26c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t* signal_out, 27c55a96383497a772a307b346368133960b02ad03Eric Laurent int32_t* filter_state, 28c55a96383497a772a307b346368133960b02ad03Eric Laurent int in_length) { 29c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t tmp16_1 = 0, tmp16_2 = 0; 30c55a96383497a772a307b346368133960b02ad03Eric Laurent int32_t tmp32_1 = filter_state[0]; 31c55a96383497a772a307b346368133960b02ad03Eric Laurent int32_t tmp32_2 = filter_state[1]; 32c55a96383497a772a307b346368133960b02ad03Eric Laurent int n = 0; 33c55a96383497a772a307b346368133960b02ad03Eric Laurent int half_length = (in_length >> 1); // Downsampling by 2 gives half length. 34c55a96383497a772a307b346368133960b02ad03Eric Laurent 35c55a96383497a772a307b346368133960b02ad03Eric Laurent // Filter coefficients in Q13, filter state in Q0. 36c55a96383497a772a307b346368133960b02ad03Eric Laurent for (n = 0; n < half_length; n++) { 37c55a96383497a772a307b346368133960b02ad03Eric Laurent // All-pass filtering upper branch. 38c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp16_1 = (int16_t) ((tmp32_1 >> 1) + 39c55a96383497a772a307b346368133960b02ad03Eric Laurent WEBRTC_SPL_MUL_16_16_RSFT(kAllPassCoefsQ13[0], *signal_in, 14)); 40c55a96383497a772a307b346368133960b02ad03Eric Laurent *signal_out = tmp16_1; 41c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp32_1 = (int32_t) (*signal_in++) - 42c55a96383497a772a307b346368133960b02ad03Eric Laurent WEBRTC_SPL_MUL_16_16_RSFT(kAllPassCoefsQ13[0], tmp16_1, 12); 43c55a96383497a772a307b346368133960b02ad03Eric Laurent 44c55a96383497a772a307b346368133960b02ad03Eric Laurent // All-pass filtering lower branch. 45c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp16_2 = (int16_t) ((tmp32_2 >> 1) + 46c55a96383497a772a307b346368133960b02ad03Eric Laurent WEBRTC_SPL_MUL_16_16_RSFT(kAllPassCoefsQ13[1], *signal_in, 14)); 47c55a96383497a772a307b346368133960b02ad03Eric Laurent *signal_out++ += tmp16_2; 48c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp32_2 = (int32_t) (*signal_in++) - 49c55a96383497a772a307b346368133960b02ad03Eric Laurent WEBRTC_SPL_MUL_16_16_RSFT(kAllPassCoefsQ13[1], tmp16_2, 12); 50c55a96383497a772a307b346368133960b02ad03Eric Laurent } 51c55a96383497a772a307b346368133960b02ad03Eric Laurent // Store the filter states. 52c55a96383497a772a307b346368133960b02ad03Eric Laurent filter_state[0] = tmp32_1; 53c55a96383497a772a307b346368133960b02ad03Eric Laurent filter_state[1] = tmp32_2; 54c55a96383497a772a307b346368133960b02ad03Eric Laurent} 55c55a96383497a772a307b346368133960b02ad03Eric Laurent 56c55a96383497a772a307b346368133960b02ad03Eric Laurent// Inserts |feature_value| into |low_value_vector|, if it is one of the 16 57c55a96383497a772a307b346368133960b02ad03Eric Laurent// smallest values the last 100 frames. Then calculates and returns the median 58c55a96383497a772a307b346368133960b02ad03Eric Laurent// of the five smallest values. 59c55a96383497a772a307b346368133960b02ad03Eric Laurentint16_t WebRtcVad_FindMinimum(VadInstT* self, 60c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t feature_value, 61c55a96383497a772a307b346368133960b02ad03Eric Laurent int channel) { 62c55a96383497a772a307b346368133960b02ad03Eric Laurent int i = 0, j = 0; 63c55a96383497a772a307b346368133960b02ad03Eric Laurent int position = -1; 64c55a96383497a772a307b346368133960b02ad03Eric Laurent // Offset to beginning of the 16 minimum values in memory. 65c55a96383497a772a307b346368133960b02ad03Eric Laurent int offset = (channel << 4); 66c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t current_median = 1600; 67c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t alpha = 0; 68c55a96383497a772a307b346368133960b02ad03Eric Laurent int32_t tmp32 = 0; 69c55a96383497a772a307b346368133960b02ad03Eric Laurent // Pointer to memory for the 16 minimum values and the age of each value of 70c55a96383497a772a307b346368133960b02ad03Eric Laurent // the |channel|. 71c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t* age_ptr = &self->index_vector[offset]; 72c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t* value_ptr = &self->low_value_vector[offset]; 73c55a96383497a772a307b346368133960b02ad03Eric Laurent int16_t *p1, *p2, *p3; 74c55a96383497a772a307b346368133960b02ad03Eric Laurent 75c55a96383497a772a307b346368133960b02ad03Eric Laurent assert(channel < NUM_CHANNELS); 76c55a96383497a772a307b346368133960b02ad03Eric Laurent 77c55a96383497a772a307b346368133960b02ad03Eric Laurent // Each value in |low_value_vector| is getting 1 loop older. 78c55a96383497a772a307b346368133960b02ad03Eric Laurent // Update age of each value in |age_ptr|, and remove old values. 79c55a96383497a772a307b346368133960b02ad03Eric Laurent for (i = 0; i < 16; i++) { 80c55a96383497a772a307b346368133960b02ad03Eric Laurent p3 = age_ptr + i; 81c55a96383497a772a307b346368133960b02ad03Eric Laurent if (*p3 != 100) { 82c55a96383497a772a307b346368133960b02ad03Eric Laurent *p3 += 1; 83c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 84c55a96383497a772a307b346368133960b02ad03Eric Laurent p1 = value_ptr + i + 1; 85c55a96383497a772a307b346368133960b02ad03Eric Laurent p2 = p3 + 1; 86c55a96383497a772a307b346368133960b02ad03Eric Laurent for (j = i; j < 16; j++) { 87c55a96383497a772a307b346368133960b02ad03Eric Laurent *(value_ptr + j) = *p1++; 88c55a96383497a772a307b346368133960b02ad03Eric Laurent *(age_ptr + j) = *p2++; 89c55a96383497a772a307b346368133960b02ad03Eric Laurent } 90c55a96383497a772a307b346368133960b02ad03Eric Laurent *(age_ptr + 15) = 101; 91c55a96383497a772a307b346368133960b02ad03Eric Laurent *(value_ptr + 15) = 10000; 92c55a96383497a772a307b346368133960b02ad03Eric Laurent } 93c55a96383497a772a307b346368133960b02ad03Eric Laurent } 94c55a96383497a772a307b346368133960b02ad03Eric Laurent 95c55a96383497a772a307b346368133960b02ad03Eric Laurent // Check if |feature_value| is smaller than any of the values in 96c55a96383497a772a307b346368133960b02ad03Eric Laurent // |low_value_vector|. If so, find the |position| where to insert the new 97c55a96383497a772a307b346368133960b02ad03Eric Laurent // value. 98c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 7)) { 99c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 3)) { 100c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 1)) { 101c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *value_ptr) { 102c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 0; 103c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 104c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 1; 105c55a96383497a772a307b346368133960b02ad03Eric Laurent } 106c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 2)) { 107c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 2; 108c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 109c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 3; 110c55a96383497a772a307b346368133960b02ad03Eric Laurent } 111c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 5)) { 112c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 4)) { 113c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 4; 114c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 115c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 5; 116c55a96383497a772a307b346368133960b02ad03Eric Laurent } 117c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 6)) { 118c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 6; 119c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 120c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 7; 121c55a96383497a772a307b346368133960b02ad03Eric Laurent } 122c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 15)) { 123c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 11)) { 124c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 9)) { 125c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 8)) { 126c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 8; 127c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 128c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 9; 129c55a96383497a772a307b346368133960b02ad03Eric Laurent } 130c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 10)) { 131c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 10; 132c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 133c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 11; 134c55a96383497a772a307b346368133960b02ad03Eric Laurent } 135c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 13)) { 136c55a96383497a772a307b346368133960b02ad03Eric Laurent if (feature_value < *(value_ptr + 12)) { 137c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 12; 138c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 139c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 13; 140c55a96383497a772a307b346368133960b02ad03Eric Laurent } 141c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (feature_value < *(value_ptr + 14)) { 142c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 14; 143c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 144c55a96383497a772a307b346368133960b02ad03Eric Laurent position = 15; 145c55a96383497a772a307b346368133960b02ad03Eric Laurent } 146c55a96383497a772a307b346368133960b02ad03Eric Laurent } 147c55a96383497a772a307b346368133960b02ad03Eric Laurent 148c55a96383497a772a307b346368133960b02ad03Eric Laurent // If we have a new small value, put it in the correct position and shift 149c55a96383497a772a307b346368133960b02ad03Eric Laurent // larger values up. 150c55a96383497a772a307b346368133960b02ad03Eric Laurent if (position > -1) { 151c55a96383497a772a307b346368133960b02ad03Eric Laurent for (i = 15; i > position; i--) { 152c55a96383497a772a307b346368133960b02ad03Eric Laurent j = i - 1; 153c55a96383497a772a307b346368133960b02ad03Eric Laurent *(value_ptr + i) = *(value_ptr + j); 154c55a96383497a772a307b346368133960b02ad03Eric Laurent *(age_ptr + i) = *(age_ptr + j); 155c55a96383497a772a307b346368133960b02ad03Eric Laurent } 156c55a96383497a772a307b346368133960b02ad03Eric Laurent *(value_ptr + position) = feature_value; 157c55a96383497a772a307b346368133960b02ad03Eric Laurent *(age_ptr + position) = 1; 158c55a96383497a772a307b346368133960b02ad03Eric Laurent } 159c55a96383497a772a307b346368133960b02ad03Eric Laurent 160c55a96383497a772a307b346368133960b02ad03Eric Laurent // Get |current_median|. 161c55a96383497a772a307b346368133960b02ad03Eric Laurent if (self->frame_counter > 2) { 162c55a96383497a772a307b346368133960b02ad03Eric Laurent current_median = *(value_ptr + 2); 163c55a96383497a772a307b346368133960b02ad03Eric Laurent } else if (self->frame_counter > 0) { 164c55a96383497a772a307b346368133960b02ad03Eric Laurent current_median = *value_ptr; 165c55a96383497a772a307b346368133960b02ad03Eric Laurent } 166c55a96383497a772a307b346368133960b02ad03Eric Laurent 167c55a96383497a772a307b346368133960b02ad03Eric Laurent // Smooth the median value. 168c55a96383497a772a307b346368133960b02ad03Eric Laurent if (self->frame_counter > 0) { 169c55a96383497a772a307b346368133960b02ad03Eric Laurent if (current_median < self->mean_value[channel]) { 170c55a96383497a772a307b346368133960b02ad03Eric Laurent alpha = (int16_t) ALPHA1; // 0.2 in Q15. 171c55a96383497a772a307b346368133960b02ad03Eric Laurent } else { 172c55a96383497a772a307b346368133960b02ad03Eric Laurent alpha = (int16_t) ALPHA2; // 0.99 in Q15. 173c55a96383497a772a307b346368133960b02ad03Eric Laurent } 174c55a96383497a772a307b346368133960b02ad03Eric Laurent } 175c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp32 = WEBRTC_SPL_MUL_16_16(alpha + 1, self->mean_value[channel]); 176c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp32 += WEBRTC_SPL_MUL_16_16(WEBRTC_SPL_WORD16_MAX - alpha, current_median); 177c55a96383497a772a307b346368133960b02ad03Eric Laurent tmp32 += 16384; 178c55a96383497a772a307b346368133960b02ad03Eric Laurent self->mean_value[channel] = (int16_t) (tmp32 >> 15); 179c55a96383497a772a307b346368133960b02ad03Eric Laurent 180c55a96383497a772a307b346368133960b02ad03Eric Laurent return self->mean_value[channel]; 181c55a96383497a772a307b346368133960b02ad03Eric Laurent} 182