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Rev | Author | Line No. | Line |
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2 | pj | 1 | /* |
2 | * Mpeg Layer-1,2,3 audio decoder |
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3 | * ------------------------------ |
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4 | * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved. |
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5 | * See also 'README' |
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6 | * version for slower machines .. decodes only every fourth sample |
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7 | * dunno why it sounds THIS annoying (maybe we should adapt the window?) |
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8 | * absolutely not optimized for this operation |
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9 | */ |
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10 | |||
11 | #include <stdlib.h> |
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12 | #include <math.h> |
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13 | #include <string.h> |
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14 | |||
15 | #include "mpg123.h" |
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16 | |||
17 | #define WRITE_SAMPLE(samples,sum,clip) \ |
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18 | if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \ |
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19 | else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \ |
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20 | else { *(samples) = sum; } |
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21 | |||
22 | int synth_4to1_8bit(real *bandPtr,int channel,unsigned char *samples) |
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23 | { |
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24 | short samples_tmp[16]; |
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25 | short *tmp1 = samples_tmp + channel; |
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26 | int i,ret; |
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27 | |||
28 | samples += channel; |
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29 | ret = synth_4to1(bandPtr,channel,(unsigned char *) samples_tmp); |
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30 | |||
31 | for(i=0;i<8;i++) { |
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32 | *samples = conv16to8[*tmp1>>4]; |
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33 | samples += 2; |
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34 | tmp1 += 2; |
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35 | } |
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36 | |||
37 | return ret; |
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38 | } |
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39 | |||
40 | int synth_4to1_8bit_mono(real *bandPtr,unsigned char *samples) |
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41 | { |
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42 | short samples_tmp[16]; |
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43 | short *tmp1 = samples_tmp; |
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44 | int i,ret; |
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45 | |||
46 | ret = synth_4to1(bandPtr,0,(unsigned char *) samples_tmp); |
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47 | |||
48 | for(i=0;i<8;i++) { |
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49 | *samples++ = conv16to8[*tmp1>>4]; |
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50 | *samples++ = conv16to8[*tmp1>>4]; |
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51 | tmp1 += 2; |
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52 | } |
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53 | |||
54 | return ret; |
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55 | } |
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56 | |||
57 | int synth_4to1_mono(real *bandPtr,unsigned char *samples) |
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58 | { |
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59 | int i,ret = synth_4to1(bandPtr,0,samples); |
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60 | for(i=0;i<8;i++) { |
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61 | ((short *)samples)[1] = ((short *)samples)[0]; |
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62 | samples+=4; |
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63 | } |
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64 | return ret; |
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65 | } |
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66 | |||
67 | int synth_4to1(real *bandPtr,int channel,unsigned char *out) |
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68 | { |
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69 | static real buffs[2][2][0x110]; |
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70 | static const int step = 2; |
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71 | static int bo = 1; |
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72 | short *samples = (short *) out; |
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73 | |||
74 | real *b0,(*buf)[0x110]; |
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75 | int clip = 0; |
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76 | int bo1; |
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77 | |||
78 | if(!channel) { |
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79 | bo--; |
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80 | bo &= 0xf; |
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81 | buf = buffs[0]; |
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82 | } |
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83 | else { |
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84 | samples++; |
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85 | buf = buffs[1]; |
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86 | } |
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87 | |||
88 | if(bo & 0x1) { |
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89 | b0 = buf[0]; |
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90 | bo1 = bo; |
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91 | dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr); |
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92 | } |
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93 | else { |
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94 | b0 = buf[1]; |
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95 | bo1 = bo+1; |
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96 | dct64(buf[0]+bo,buf[1]+bo+1,bandPtr); |
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97 | } |
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98 | |||
99 | { |
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100 | register int j; |
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101 | real *window = decwin + 16 - bo1; |
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102 | |||
103 | for (j=4;j;j--,b0+=0x30,window+=0x70) |
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104 | { |
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105 | real sum; |
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106 | sum = *window++ * *b0++; |
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107 | sum -= *window++ * *b0++; |
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108 | sum += *window++ * *b0++; |
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109 | sum -= *window++ * *b0++; |
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110 | sum += *window++ * *b0++; |
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111 | sum -= *window++ * *b0++; |
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112 | sum += *window++ * *b0++; |
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113 | sum -= *window++ * *b0++; |
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114 | sum += *window++ * *b0++; |
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115 | sum -= *window++ * *b0++; |
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116 | sum += *window++ * *b0++; |
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117 | sum -= *window++ * *b0++; |
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118 | sum += *window++ * *b0++; |
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119 | sum -= *window++ * *b0++; |
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120 | sum += *window++ * *b0++; |
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121 | sum -= *window++ * *b0++; |
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122 | |||
123 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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124 | #if 0 |
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125 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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126 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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127 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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128 | #endif |
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129 | } |
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130 | |||
131 | { |
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132 | real sum; |
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133 | sum = window[0x0] * b0[0x0]; |
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134 | sum += window[0x2] * b0[0x2]; |
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135 | sum += window[0x4] * b0[0x4]; |
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136 | sum += window[0x6] * b0[0x6]; |
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137 | sum += window[0x8] * b0[0x8]; |
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138 | sum += window[0xA] * b0[0xA]; |
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139 | sum += window[0xC] * b0[0xC]; |
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140 | sum += window[0xE] * b0[0xE]; |
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141 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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142 | #if 0 |
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143 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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144 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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145 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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146 | #endif |
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147 | b0-=0x40,window-=0x80; |
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148 | } |
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149 | window += bo1<<1; |
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150 | |||
151 | for (j=3;j;j--,b0-=0x50,window-=0x70) |
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152 | { |
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153 | real sum; |
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154 | sum = -*(--window) * *b0++; |
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155 | sum -= *(--window) * *b0++; |
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156 | sum -= *(--window) * *b0++; |
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157 | sum -= *(--window) * *b0++; |
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158 | sum -= *(--window) * *b0++; |
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159 | sum -= *(--window) * *b0++; |
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160 | sum -= *(--window) * *b0++; |
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161 | sum -= *(--window) * *b0++; |
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162 | sum -= *(--window) * *b0++; |
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163 | sum -= *(--window) * *b0++; |
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164 | sum -= *(--window) * *b0++; |
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165 | sum -= *(--window) * *b0++; |
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166 | sum -= *(--window) * *b0++; |
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167 | sum -= *(--window) * *b0++; |
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168 | sum -= *(--window) * *b0++; |
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169 | sum -= *(--window) * *b0++; |
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170 | |||
171 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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172 | #if 0 |
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173 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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174 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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175 | WRITE_SAMPLE(samples,sum,clip); samples += step; |
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176 | #endif |
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177 | } |
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178 | } |
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179 | |||
180 | return clip; |
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181 | } |
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182 | |||
183 |