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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 | * |
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| 7 | * slighlty optimized for machines without autoincrement/decrement. |
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| 8 | * The performance is highly compiler dependend. Maybe |
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| 9 | * the decode.c version for 'normal' processor may be faster |
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| 10 | * even for Intel processors. |
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| 11 | */ |
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| 12 | |||
| 13 | #include <stdlib.h> |
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| 14 | #include <math.h> |
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| 15 | #include <string.h> |
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| 16 | |||
| 17 | #include "mpg123.h" |
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| 18 | |||
| 19 | #define WRITE_SAMPLE(samples,sum,clip) \ |
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| 20 | if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \ |
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| 21 | else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \ |
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| 22 | else { *(samples) = sum; } |
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| 23 | |||
| 24 | int synth_1to1_8bit(real *bandPtr,int channel,unsigned char *samples) |
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| 25 | { |
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| 26 | short samples_tmp[64]; |
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| 27 | short *tmp1 = samples_tmp + channel; |
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| 28 | int i,ret; |
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| 29 | |||
| 30 | samples += channel; |
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| 31 | ret = synth_1to1(bandPtr,channel,(unsigned char *)samples_tmp); |
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| 32 | |||
| 33 | for(i=0;i<32;i++) { |
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| 34 | *samples = conv16to8[*tmp1>>4]; |
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| 35 | samples += 2; |
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| 36 | tmp1 += 2; |
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| 37 | } |
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| 38 | |||
| 39 | return ret; |
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| 40 | } |
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| 41 | |||
| 42 | int synth_1to1_8bit_mono(real *bandPtr,unsigned char *samples) |
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| 43 | { |
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| 44 | short samples_tmp[64]; |
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| 45 | short *tmp1 = samples_tmp; |
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| 46 | int i,ret; |
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| 47 | |||
| 48 | ret = synth_1to1(bandPtr,0,(unsigned char *)samples_tmp); |
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| 49 | |||
| 50 | for(i=0;i<32;i++) { |
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| 51 | *samples++ = conv16to8[*tmp1>>4]; |
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| 52 | *samples++ = conv16to8[*tmp1>>4]; |
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| 53 | tmp1 += 2; |
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| 54 | } |
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| 55 | |||
| 56 | return ret; |
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| 57 | } |
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| 58 | |||
| 59 | int synth_1to1_mono(real *bandPtr,unsigned char *samples) |
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| 60 | { |
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| 61 | int i,ret = synth_1to1(bandPtr,0,samples); |
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| 62 | for(i=0;i<32;i++) { |
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| 63 | ((short *)samples)[1] = ((short *)samples)[0]; |
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| 64 | samples+=4; |
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| 65 | } |
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| 66 | return ret; |
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| 67 | } |
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| 68 | |||
| 69 | int synth_1to1(real *bandPtr,int channel,unsigned char *out) |
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| 70 | { |
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| 71 | static real buffs[2][2][0x110]; |
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| 72 | static const int step = 2; |
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| 73 | static int bo = 1; |
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| 74 | short *samples = (short *) out; |
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| 75 | |||
| 76 | real *b0,(*buf)[0x110]; |
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| 77 | int clip = 0; |
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| 78 | int bo1; |
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| 79 | |||
| 80 | if(!channel) { |
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| 81 | bo--; |
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| 82 | bo &= 0xf; |
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| 83 | buf = buffs[0]; |
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| 84 | } |
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| 85 | else { |
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| 86 | samples++; |
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| 87 | buf = buffs[1]; |
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| 88 | } |
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| 89 | |||
| 90 | if(bo & 0x1) { |
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| 91 | b0 = buf[0]; |
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| 92 | bo1 = bo; |
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| 93 | dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr); |
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| 94 | } |
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| 95 | else { |
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| 96 | b0 = buf[1]; |
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| 97 | bo1 = bo+1; |
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| 98 | dct64(buf[0]+bo,buf[1]+bo+1,bandPtr); |
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| 99 | } |
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| 100 | |||
| 101 | { |
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| 102 | register int j; |
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| 103 | real *window = decwin + 16 - bo1; |
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| 104 | |||
| 105 | for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step) |
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| 106 | { |
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| 107 | real sum; |
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| 108 | sum = window[0x0] * b0[0x0]; |
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| 109 | sum -= window[0x1] * b0[0x1]; |
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| 110 | sum += window[0x2] * b0[0x2]; |
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| 111 | sum -= window[0x3] * b0[0x3]; |
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| 112 | sum += window[0x4] * b0[0x4]; |
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| 113 | sum -= window[0x5] * b0[0x5]; |
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| 114 | sum += window[0x6] * b0[0x6]; |
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| 115 | sum -= window[0x7] * b0[0x7]; |
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| 116 | sum += window[0x8] * b0[0x8]; |
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| 117 | sum -= window[0x9] * b0[0x9]; |
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| 118 | sum += window[0xA] * b0[0xA]; |
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| 119 | sum -= window[0xB] * b0[0xB]; |
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| 120 | sum += window[0xC] * b0[0xC]; |
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| 121 | sum -= window[0xD] * b0[0xD]; |
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| 122 | sum += window[0xE] * b0[0xE]; |
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| 123 | sum -= window[0xF] * b0[0xF]; |
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| 124 | |||
| 125 | WRITE_SAMPLE(samples,sum,clip); |
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| 126 | } |
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| 127 | |||
| 128 | { |
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| 129 | real sum; |
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| 130 | sum = window[0x0] * b0[0x0]; |
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| 131 | sum += window[0x2] * b0[0x2]; |
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| 132 | sum += window[0x4] * b0[0x4]; |
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| 133 | sum += window[0x6] * b0[0x6]; |
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| 134 | sum += window[0x8] * b0[0x8]; |
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| 135 | sum += window[0xA] * b0[0xA]; |
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| 136 | sum += window[0xC] * b0[0xC]; |
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| 137 | sum += window[0xE] * b0[0xE]; |
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| 138 | WRITE_SAMPLE(samples,sum,clip); |
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| 139 | b0-=0x10,window-=0x20,samples+=step; |
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| 140 | } |
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| 141 | window += bo1<<1; |
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| 142 | |||
| 143 | for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step) |
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| 144 | { |
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| 145 | real sum; |
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| 146 | sum = -window[-0x1] * b0[0x0]; |
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| 147 | sum -= window[-0x2] * b0[0x1]; |
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| 148 | sum -= window[-0x3] * b0[0x2]; |
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| 149 | sum -= window[-0x4] * b0[0x3]; |
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| 150 | sum -= window[-0x5] * b0[0x4]; |
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| 151 | sum -= window[-0x6] * b0[0x5]; |
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| 152 | sum -= window[-0x7] * b0[0x6]; |
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| 153 | sum -= window[-0x8] * b0[0x7]; |
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| 154 | sum -= window[-0x9] * b0[0x8]; |
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| 155 | sum -= window[-0xA] * b0[0x9]; |
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| 156 | sum -= window[-0xB] * b0[0xA]; |
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| 157 | sum -= window[-0xC] * b0[0xB]; |
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| 158 | sum -= window[-0xD] * b0[0xC]; |
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| 159 | sum -= window[-0xE] * b0[0xD]; |
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| 160 | sum -= window[-0xF] * b0[0xE]; |
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| 161 | sum -= window[-0x0] * b0[0xF]; |
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| 162 | |||
| 163 | WRITE_SAMPLE(samples,sum,clip); |
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| 164 | } |
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| 165 | } |
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| 166 | return clip; |
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| 167 | } |
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| 168 | |||
| 169 |