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2 /******************************************************************
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3
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4 iLBC Speech Coder ANSI-C Source Code
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5
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6 iCBConstruct.c
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7
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8 Copyright (C) The Internet Society (2004).
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9 All Rights Reserved.
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10
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11 ******************************************************************/
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12
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13 #include <math.h>
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14
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15 #include "iLBC_define.h"
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16 #include "gainquant.h"
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17 #include "getCBvec.h"
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18
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19 /*----------------------------------------------------------------*
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20 * Convert the codebook indexes to make the search easier
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21 *---------------------------------------------------------------*/
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22
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23
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24
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25
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26
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27
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28 void index_conv_enc(int *index /* (i/o) Codebook indexes */
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29 )
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30 {
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31 int k;
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32
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33 for (k = 1; k < CB_NSTAGES; k++) {
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34
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35 if ((index[k] >= 108) && (index[k] < 172)) {
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36 index[k] -= 64;
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37 } else if (index[k] >= 236) {
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38 index[k] -= 128;
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39 } else {
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40 /* ERROR */
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41 }
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42 }
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43 }
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44
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45 void index_conv_dec(int *index /* (i/o) Codebook indexes */
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46 )
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47 {
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48 int k;
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49
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50 for (k = 1; k < CB_NSTAGES; k++) {
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51
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52 if ((index[k] >= 44) && (index[k] < 108)) {
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53 index[k] += 64;
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54 } else if ((index[k] >= 108) && (index[k] < 128)) {
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55 index[k] += 128;
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56 } else {
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57 /* ERROR */
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58 }
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59 }
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60 }
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61
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62 /*----------------------------------------------------------------*
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63 * Construct decoded vector from codebook and gains.
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64 *---------------------------------------------------------------*/
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65
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66 void iCBConstruct(float *decvector, /* (o) Decoded vector */
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67 int *index, /* (i) Codebook indices */
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68 int *gain_index, /* (i) Gain quantization indices */
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69 float *mem, /* (i) Buffer for codevector construction */
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70 int lMem, /* (i) Length of buffer */
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71 int veclen, /* (i) Length of vector */
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72 int nStages /* (i) Number of codebook stages */
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73 )
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74 {
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75 int j, k;
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76
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77
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78
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79
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80
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81 float gain[CB_NSTAGES];
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82 float cbvec[SUBL];
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83
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84 /* gain de-quantization */
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85
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86 gain[0] = gaindequant(gain_index[0], 1.0, 32);
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87 if (nStages > 1) {
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88 gain[1] = gaindequant(gain_index[1], (float) fabs(gain[0]), 16);
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89 }
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90 if (nStages > 2) {
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91 gain[2] = gaindequant(gain_index[2], (float) fabs(gain[1]), 8);
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92 }
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93
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94 /* codebook vector construction and construction of
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95 total vector */
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96
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97 getCBvec(cbvec, mem, index[0], lMem, veclen);
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98 for (j = 0; j < veclen; j++) {
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99 decvector[j] = gain[0] * cbvec[j];
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100 }
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101 if (nStages > 1) {
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102 for (k = 1; k < nStages; k++) {
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103 getCBvec(cbvec, mem, index[k], lMem, veclen);
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104 for (j = 0; j < veclen; j++) {
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105 decvector[j] += gain[k] * cbvec[j];
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106 }
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107 }
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108 }
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109 }
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