562
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1 /*
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2 layer2.c: the layer 2 decoder, root of mpg123
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3
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4 copyright 1994-2007 by the mpg123 project - free software under the terms of the LGPL 2.1
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5 see COPYING and AUTHORS files in distribution or http://mpg123.org
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6 initially written by Michael Hipp
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7
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8 mpg123 started as mp2 decoder a long time ago...
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9 */
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10
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11
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12 #include "mpg123lib_intern.h"
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13 #include "l2tables.h"
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14 #include "getbits.h"
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15
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16 static int grp_3tab[32 * 3] = { 0, }; /* used: 27 */
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17 static int grp_5tab[128 * 3] = { 0, }; /* used: 125 */
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18 static int grp_9tab[1024 * 3] = { 0, }; /* used: 729 */
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19
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20 static const double mulmul[27] =
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21 {
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22 0.0 , -2.0/3.0 , 2.0/3.0 ,
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23 2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 ,
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24 2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 ,
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25 2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 ,
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26 -4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 ,
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27 -8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0
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28 };
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29
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30 void init_layer2(void)
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31 {
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32 const int base[3][9] = {
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33 { 1 , 0, 2 , } ,
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34 { 17, 18, 0 , 19, 20 , } ,
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35 { 21, 1, 22, 23, 0, 24, 25, 2, 26 } };
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36 int i,j,k,l,len;
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37 const int tablen[3] = { 3 , 5 , 9 };
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38 int *itable;
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39 int *tables[3] = { grp_3tab , grp_5tab , grp_9tab };
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40
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41 for(i=0;i<3;i++)
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42 {
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43 itable = tables[i];
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44 len = tablen[i];
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45 for(j=0;j<len;j++)
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46 for(k=0;k<len;k++)
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47 for(l=0;l<len;l++)
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48 {
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49 *itable++ = base[i][l];
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50 *itable++ = base[i][k];
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51 *itable++ = base[i][j];
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52 }
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53 }
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54 }
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55
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56 void init_layer2_stuff(mpg123_handle *fr)
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57 {
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58 int k;
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59 real *table;
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60 for(k=0;k<27;k++)
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61 {
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62 table = opt_init_layer2_table(fr)(fr, fr->muls[k], mulmul[k]);
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63 *table++ = 0.0;
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64 }
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65 }
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66
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67 real* init_layer2_table(mpg123_handle *fr, real *table, double m)
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68 {
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69 int i,j;
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70 for(j=3,i=0;i<63;i++,j--)
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71 *table++ = m * pow(2.0,(double) j / 3.0);
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72
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73 return table;
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74 }
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75
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76 #ifdef OPT_MMXORSSE
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77 real* init_layer2_table_mmx(mpg123_handle *fr, real *table, double m)
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78 {
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79 int i,j;
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80 if(!fr->p.down_sample)
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81 for(j=3,i=0;i<63;i++,j--)
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82 *table++ = 16384 * m * pow(2.0,(double) j / 3.0);
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83 else
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84 for(j=3,i=0;i<63;i++,j--)
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85 *table++ = m * pow(2.0,(double) j / 3.0);
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86
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87 return table;
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88 }
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89 #endif
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90
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91 void II_step_one(unsigned int *bit_alloc,int *scale,mpg123_handle *fr)
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92 {
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93 int stereo = fr->stereo-1;
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94 int sblimit = fr->II_sblimit;
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95 int jsbound = fr->jsbound;
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96 int sblimit2 = fr->II_sblimit<<stereo;
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97 const struct al_table *alloc1 = fr->alloc;
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98 int i;
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99 /* static unsigned int scfsi_buf[64]; */
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100 unsigned int scfsi_buf[64];
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101 unsigned int *scfsi,*bita;
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102 int sc,step;
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103
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104 bita = bit_alloc;
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105 if(stereo)
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106 {
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107 for (i=jsbound;i;i--,alloc1+=(1<<step))
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108 {
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109 step=alloc1->bits;
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110 *bita++ = (char) getbits(fr, step);
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111 *bita++ = (char) getbits(fr, step);
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112 }
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113 for (i=sblimit-jsbound;i;i--,alloc1+=(1<<step))
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114 {
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115 step=alloc1->bits;
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116 bita[0] = (char) getbits(fr, step);
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117 bita[1] = bita[0];
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118 bita+=2;
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119 }
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120 bita = bit_alloc;
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121 scfsi=scfsi_buf;
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122 for (i=sblimit2;i;i--)
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123 if (*bita++)
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124 *scfsi++ = (char) getbits_fast(fr, 2);
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125 }
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126 else /* mono */
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127 {
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128 for (i=sblimit;i;i--,alloc1+=(1<<step))
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129 {
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130 step=alloc1->bits;
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131 *bita++ = (char) getbits(fr, step);
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132 }
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133 bita = bit_alloc;
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134 scfsi=scfsi_buf;
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135 for (i=sblimit;i;i--)
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136 if (*bita++)
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137 *scfsi++ = (char) getbits_fast(fr, 2);
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138 }
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139
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140 bita = bit_alloc;
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141 scfsi=scfsi_buf;
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142 for (i=sblimit2;i;i--)
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143 if (*bita++)
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144 switch (*scfsi++)
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145 {
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146 case 0:
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147 *scale++ = getbits_fast(fr, 6);
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148 *scale++ = getbits_fast(fr, 6);
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149 *scale++ = getbits_fast(fr, 6);
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150 break;
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151 case 1 :
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152 *scale++ = sc = getbits_fast(fr, 6);
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153 *scale++ = sc;
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154 *scale++ = getbits_fast(fr, 6);
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155 break;
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156 case 2:
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157 *scale++ = sc = getbits_fast(fr, 6);
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158 *scale++ = sc;
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159 *scale++ = sc;
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160 break;
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161 default: /* case 3 */
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162 *scale++ = getbits_fast(fr, 6);
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163 *scale++ = sc = getbits_fast(fr, 6);
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164 *scale++ = sc;
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165 break;
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166 }
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167
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168 }
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169
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170 void II_step_two(unsigned int *bit_alloc,real fraction[2][4][SBLIMIT],int *scale,mpg123_handle *fr,int x1)
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171 {
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172 int i,j,k,ba;
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173 int stereo = fr->stereo;
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174 int sblimit = fr->II_sblimit;
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175 int jsbound = fr->jsbound;
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176 const struct al_table *alloc2,*alloc1 = fr->alloc;
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177 unsigned int *bita=bit_alloc;
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178 int d1,step;
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179
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180 for (i=0;i<jsbound;i++,alloc1+=(1<<step))
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181 {
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182 step = alloc1->bits;
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183 for (j=0;j<stereo;j++)
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184 {
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185 if ( (ba=*bita++) )
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186 {
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187 k=(alloc2 = alloc1+ba)->bits;
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188 if( (d1=alloc2->d) < 0)
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189 {
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190 real cm=fr->muls[k][scale[x1]];
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191 fraction[j][0][i] = ((real) ((int)getbits(fr, k) + d1)) * cm;
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192 fraction[j][1][i] = ((real) ((int)getbits(fr, k) + d1)) * cm;
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193 fraction[j][2][i] = ((real) ((int)getbits(fr, k) + d1)) * cm;
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194 }
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195 else
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196 {
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197 const int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
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198 unsigned int idx,*tab,m=scale[x1];
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199 idx = (unsigned int) getbits(fr, k);
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200 tab = (unsigned int *) (table[d1] + idx + idx + idx);
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201 fraction[j][0][i] = fr->muls[*tab++][m];
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202 fraction[j][1][i] = fr->muls[*tab++][m];
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203 fraction[j][2][i] = fr->muls[*tab][m];
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204 }
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205 scale+=3;
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206 }
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207 else
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208 fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
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209 }
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210 }
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211
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212 for (i=jsbound;i<sblimit;i++,alloc1+=(1<<step))
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213 {
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214 step = alloc1->bits;
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215 bita++; /* channel 1 and channel 2 bitalloc are the same */
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216 if ( (ba=*bita++) )
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217 {
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218 k=(alloc2 = alloc1+ba)->bits;
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219 if( (d1=alloc2->d) < 0)
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220 {
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221 real cm;
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222 cm=fr->muls[k][scale[x1+3]];
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223 fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
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224 fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
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225 fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
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226 cm=fr->muls[k][scale[x1]];
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227 fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm;
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228 }
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229 else
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230 {
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231 const int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
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232 unsigned int idx,*tab,m1,m2;
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233 m1 = scale[x1]; m2 = scale[x1+3];
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234 idx = (unsigned int) getbits(fr, k);
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235 tab = (unsigned int *) (table[d1] + idx + idx + idx);
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236 fraction[0][0][i] = fr->muls[*tab][m1]; fraction[1][0][i] = fr->muls[*tab++][m2];
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237 fraction[0][1][i] = fr->muls[*tab][m1]; fraction[1][1][i] = fr->muls[*tab++][m2];
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238 fraction[0][2][i] = fr->muls[*tab][m1]; fraction[1][2][i] = fr->muls[*tab][m2];
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239 }
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240 scale+=6;
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241 }
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242 else {
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243 fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
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244 fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
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245 }
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246 /*
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247 should we use individual scalefac for channel 2 or
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248 is the current way the right one , where we just copy channel 1 to
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249 channel 2 ??
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250 The current 'strange' thing is, that we throw away the scalefac
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251 values for the second channel ...!!
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252 -> changed .. now we use the scalefac values of channel one !!
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253 */
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254 }
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255
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256 if(sblimit > (fr->down_sample_sblimit) )
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257 sblimit = fr->down_sample_sblimit;
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258
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259 for(i=sblimit;i<SBLIMIT;i++)
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260 for (j=0;j<stereo;j++)
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261 fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
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262
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263 }
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264
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265 static void II_select_table(mpg123_handle *fr)
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266 {
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267 const int translate[3][2][16] =
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268 { { { 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0 } ,
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269 { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0 } } ,
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270 { { 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0 } ,
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271 { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0 } } ,
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272 { { 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0 } ,
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273 { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0 } } };
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274
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275 int table,sblim;
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276 const struct al_table *tables[5] =
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277 { alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 };
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278 const int sblims[5] = { 27 , 30 , 8, 12 , 30 };
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279
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280 if(fr->sampling_frequency >= 3) /* Or equivalent: (fr->lsf == 1) */
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281 table = 4;
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282 else
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283 table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index];
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284 sblim = sblims[table];
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285
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286 fr->alloc = tables[table];
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287 fr->II_sblimit = sblim;
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288 }
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289
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290
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291 int do_layer2(mpg123_handle *fr)
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292 {
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293 int clip=0;
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294 int i,j;
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295 int stereo = fr->stereo;
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296 ALIGNED(16) real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
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297 unsigned int bit_alloc[64];
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298 int scale[192];
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299 int single = fr->single;
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300
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301 II_select_table(fr);
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302 fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
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303 (fr->mode_ext<<2)+4 : fr->II_sblimit;
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304
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305 if (fr->jsbound > fr->II_sblimit) {
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306 fprintf(stderr, "Truncating stereo boundary to sideband limit.\n");
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307 fr->jsbound=fr->II_sblimit;
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308 }
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309
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310 if(stereo == 1 || single == SINGLE_MIX) /* also, mix not really handled */
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311 single = SINGLE_LEFT;
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312
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313 II_step_one(bit_alloc, scale, fr);
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314
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315 for (i=0;i<SCALE_BLOCK;i++)
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316 {
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317 II_step_two(bit_alloc,fraction,scale,fr,i>>2);
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318 for (j=0;j<3;j++)
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319 {
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320 if(single != SINGLE_STEREO)
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321 {
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322 clip += (fr->synth_mono) (fraction[single][j], fr);
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323 }
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324 else
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325 {
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326 clip += (fr->synth) (fraction[0][j], 0, fr, 0);
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327 clip += (fr->synth) (fraction[1][j], 1, fr, 1);
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328 }
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329 }
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330 }
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331
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332 return clip;
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333 }
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334
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335
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