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Rev | Author | Line No. | Line |
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576 | serge | 1 | /* |
2 | layer1.c: the layer 1 decoder |
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3 | |||
4 | copyright 1995-2006 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.de |
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6 | initially written by Michael Hipp |
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7 | |||
8 | may have a few bugs after last optimization ... |
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9 | */ |
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10 | |||
11 | #include "mpg123.h" |
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12 | |||
13 | void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT],struct frame *fr) |
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14 | { |
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15 | unsigned int *ba=balloc; |
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16 | unsigned int *sca = (unsigned int *) scale_index; |
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17 | |||
18 | if(fr->stereo == 2) { |
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19 | int i; |
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20 | int jsbound = fr->jsbound; |
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21 | for (i=0;i |
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22 | *ba++ = getbits(4); |
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23 | *ba++ = getbits(4); |
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24 | } |
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25 | for (i=jsbound;i |
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26 | *ba++ = getbits(4); |
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27 | |||
28 | ba = balloc; |
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29 | |||
30 | for (i=0;i |
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31 | if ((*ba++)) |
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32 | *sca++ = getbits(6); |
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33 | if ((*ba++)) |
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34 | *sca++ = getbits(6); |
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35 | } |
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36 | for (i=jsbound;i |
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37 | if ((*ba++)) { |
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38 | *sca++ = getbits(6); |
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39 | *sca++ = getbits(6); |
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40 | } |
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41 | } |
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42 | else { |
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43 | int i; |
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44 | for (i=0;i |
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45 | *ba++ = getbits(4); |
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46 | ba = balloc; |
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47 | for (i=0;i |
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48 | if ((*ba++)) |
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49 | *sca++ = getbits(6); |
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50 | } |
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51 | } |
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52 | |||
53 | void I_step_two(real fraction[2][SBLIMIT],unsigned int balloc[2*SBLIMIT], |
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54 | unsigned int scale_index[2][SBLIMIT],struct frame *fr) |
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55 | { |
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56 | int i,n; |
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57 | int smpb[2*SBLIMIT]; /* values: 0-65535 */ |
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58 | int *sample; |
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59 | register unsigned int *ba; |
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60 | register unsigned int *sca = (unsigned int *) scale_index; |
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61 | |||
62 | if(fr->stereo == 2) { |
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63 | int jsbound = fr->jsbound; |
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64 | register real *f0 = fraction[0]; |
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65 | register real *f1 = fraction[1]; |
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66 | ba = balloc; |
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67 | for (sample=smpb,i=0;i |
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68 | if ((n = *ba++)) |
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69 | *sample++ = getbits(n+1); |
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70 | if ((n = *ba++)) |
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71 | *sample++ = getbits(n+1); |
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72 | } |
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73 | for (i=jsbound;i |
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74 | if ((n = *ba++)) |
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75 | *sample++ = getbits(n+1); |
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76 | |||
77 | ba = balloc; |
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78 | for (sample=smpb,i=0;i |
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79 | if((n=*ba++)) |
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80 | *f0++ = (real) ( ((-1)< |
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81 | else |
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82 | *f0++ = 0.0; |
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83 | if((n=*ba++)) |
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84 | *f1++ = (real) ( ((-1)< |
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85 | else |
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86 | *f1++ = 0.0; |
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87 | } |
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88 | for (i=jsbound;i |
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89 | if ((n=*ba++)) { |
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90 | real samp = ( ((-1)< |
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91 | *f0++ = samp * muls[n+1][*sca++]; |
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92 | *f1++ = samp * muls[n+1][*sca++]; |
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93 | } |
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94 | else |
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95 | *f0++ = *f1++ = 0.0; |
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96 | } |
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97 | for(i=fr->down_sample_sblimit;i<32;i++) |
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98 | fraction[0][i] = fraction[1][i] = 0.0; |
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99 | } |
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100 | else { |
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101 | register real *f0 = fraction[0]; |
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102 | ba = balloc; |
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103 | for (sample=smpb,i=0;i |
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104 | if ((n = *ba++)) |
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105 | *sample++ = getbits(n+1); |
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106 | ba = balloc; |
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107 | for (sample=smpb,i=0;i |
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108 | if((n=*ba++)) |
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109 | *f0++ = (real) ( ((-1)< |
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110 | else |
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111 | *f0++ = 0.0; |
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112 | } |
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113 | for(i=fr->down_sample_sblimit;i<32;i++) |
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114 | fraction[0][i] = 0.0; |
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115 | } |
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116 | } |
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117 | |||
118 | int do_layer1(struct frame *fr,byte *pcm_sample, int *pcm_point) |
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119 | { |
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120 | int clip=0; |
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121 | int i,stereo = fr->stereo; |
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122 | unsigned int balloc[2*SBLIMIT]; |
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123 | unsigned int scale_index[2][SBLIMIT]; |
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124 | real fraction[2][SBLIMIT]; |
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125 | int single = fr->single; |
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126 | |||
127 | fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext<<2)+4 : 32; |
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128 | |||
129 | if(stereo == 1 || single == 3) |
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130 | single = 0; |
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131 | |||
132 | I_step_one(balloc,scale_index,fr); |
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133 | |||
134 | for (i=0;i |
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135 | { |
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136 | I_step_two(fraction,balloc,scale_index,fr); |
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137 | |||
138 | if(single >= 0) |
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139 | { |
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140 | clip += (fr->synth_mono)( (real *) fraction[single],pcm_sample,pcm_point); |
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141 | } |
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142 | else { |
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143 | int p1=*pcm_point; |
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144 | clip += (fr->synth)( (real *) fraction[0],0,pcm_sample,&p1); |
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145 | clip += (fr->synth)( (real *) fraction[1],1,pcm_sample,pcm_point); |
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146 | } |
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147 | } |
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148 | return clip; |
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149 | } |
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150 | |||
151 |