decim54.c revision 956c553ab0ce72f8074ad0fda2ffd66a0305700c
1/* 2 ** Copyright 2003-2010, VisualOn, Inc. 3 ** 4 ** Licensed under the Apache License, Version 2.0 (the "License"); 5 ** you may not use this file except in compliance with the License. 6 ** You may obtain a copy of the License at 7 ** 8 ** http://www.apache.org/licenses/LICENSE-2.0 9 ** 10 ** Unless required by applicable law or agreed to in writing, software 11 ** distributed under the License is distributed on an "AS IS" BASIS, 12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 ** See the License for the specific language governing permissions and 14 ** limitations under the License. 15 */ 16 17/*********************************************************************** 18* File: decim54.c * 19* * 20* Description:Decimation of 16kHz signal to 12.8kHz * 21* * 22************************************************************************/ 23 24#include "typedef.h" 25#include "basic_op.h" 26#include "acelp.h" 27#include "cnst.h" 28 29#define FAC5 5 30#define DOWN_FAC 26215 /* 4/5 in Q15 */ 31 32#define NB_COEF_DOWN 15 33 34/* Local functions */ 35static void Down_samp( 36 Word16 * sig, /* input: signal to downsampling */ 37 Word16 * sig_d, /* output: downsampled signal */ 38 Word16 L_frame_d /* input: length of output */ 39 ); 40 41/* 1/5 resolution interpolation filter (in Q14) */ 42/* -1.5dB @ 6kHz, -6dB @ 6.4kHz, -10dB @ 6.6kHz, -20dB @ 6.9kHz, -25dB @ 7kHz, -55dB @ 8kHz */ 43 44static Word16 fir_down1[4][30] = 45{ 46 {-5, 24, -50, 54, 0, -128, 294, -408, 344, 0, -647, 1505, -2379, 3034, 13107, 3034, -2379, 1505, -647, 0, 344, -408, 47 294, -128, 0, 54, -50, 24, -5, 0}, 48 49 {-6, 19, -26, 0, 77, -188, 270, -233, 0, 434, -964, 1366, -1293, 0, 12254, 6575, -2746, 1030, 0, -507, 601, -441, 50 198, 0, -95, 99, -58, 18, 0, -1}, 51 52 {-3, 9, 0, -41, 111, -170, 153, 0, -295, 649, -888, 770, 0, -1997, 9894, 9894, -1997, 0, 770, -888, 649, -295, 0, 53 153, -170, 111, -41, 0, 9, -3}, 54 55 {-1, 0, 18, -58, 99, -95, 0, 198, -441, 601, -507, 0, 1030, -2746, 6575, 12254, 0, -1293, 1366, -964, 434, 0, 56 -233, 270, -188, 77, 0, -26, 19, -6} 57}; 58 59void Init_Decim_12k8( 60 Word16 mem[] /* output: memory (2*NB_COEF_DOWN) set to zeros */ 61 ) 62{ 63 Set_zero(mem, 2 * NB_COEF_DOWN); 64 return; 65} 66 67void Decim_12k8( 68 Word16 sig16k[], /* input: signal to downsampling */ 69 Word16 lg, /* input: length of input */ 70 Word16 sig12k8[], /* output: decimated signal */ 71 Word16 mem[] /* in/out: memory (2*NB_COEF_DOWN) */ 72 ) 73{ 74 Word16 lg_down; 75 Word16 signal[L_FRAME16k + (2 * NB_COEF_DOWN)]; 76 77 Copy(mem, signal, 2 * NB_COEF_DOWN); 78 79 Copy(sig16k, signal + (2 * NB_COEF_DOWN), lg); 80 81 lg_down = (lg * DOWN_FAC)>>15; 82 83 Down_samp(signal + NB_COEF_DOWN, sig12k8, lg_down); 84 85 Copy(signal + lg, mem, 2 * NB_COEF_DOWN); 86 87 return; 88} 89 90static void Down_samp( 91 Word16 * sig, /* input: signal to downsampling */ 92 Word16 * sig_d, /* output: downsampled signal */ 93 Word16 L_frame_d /* input: length of output */ 94 ) 95{ 96 Word32 i, j, frac, pos; 97 Word16 *x, *y; 98 Word32 L_sum; 99 100 pos = 0; /* position is in Q2 -> 1/4 resolution */ 101 for (j = 0; j < L_frame_d; j++) 102 { 103 i = (pos >> 2); /* integer part */ 104 frac = pos & 3; /* fractional part */ 105 x = sig + i - NB_COEF_DOWN + 1; 106 y = (Word16 *)(fir_down1 + frac); 107 108 L_sum = vo_mult32((*x++),(*y++)); 109 L_sum += vo_mult32((*x++),(*y++)); 110 L_sum += vo_mult32((*x++),(*y++)); 111 L_sum += vo_mult32((*x++),(*y++)); 112 L_sum += vo_mult32((*x++),(*y++)); 113 L_sum += vo_mult32((*x++),(*y++)); 114 L_sum += vo_mult32((*x++),(*y++)); 115 L_sum += vo_mult32((*x++),(*y++)); 116 L_sum += vo_mult32((*x++),(*y++)); 117 L_sum += vo_mult32((*x++),(*y++)); 118 L_sum += vo_mult32((*x++),(*y++)); 119 L_sum += vo_mult32((*x++),(*y++)); 120 L_sum += vo_mult32((*x++),(*y++)); 121 L_sum += vo_mult32((*x++),(*y++)); 122 L_sum += vo_mult32((*x++),(*y++)); 123 L_sum += vo_mult32((*x++),(*y++)); 124 L_sum += vo_mult32((*x++),(*y++)); 125 L_sum += vo_mult32((*x++),(*y++)); 126 L_sum += vo_mult32((*x++),(*y++)); 127 L_sum += vo_mult32((*x++),(*y++)); 128 L_sum += vo_mult32((*x++),(*y++)); 129 L_sum += vo_mult32((*x++),(*y++)); 130 L_sum += vo_mult32((*x++),(*y++)); 131 L_sum += vo_mult32((*x++),(*y++)); 132 L_sum += vo_mult32((*x++),(*y++)); 133 L_sum += vo_mult32((*x++),(*y++)); 134 L_sum += vo_mult32((*x++),(*y++)); 135 L_sum += vo_mult32((*x++),(*y++)); 136 L_sum += vo_mult32((*x++),(*y++)); 137 L_sum += vo_mult32((*x),(*y)); 138 139 L_sum = L_shl2(L_sum, 2); 140 sig_d[j] = extract_h(L_add(L_sum, 0x8000)); 141 pos += FAC5; /* pos + 5/4 */ 142 } 143 return; 144} 145 146 147