261
|
1 /*
|
|
2 * Mpeg Layer-1,2,3 audio decoder
|
|
3 * ------------------------------
|
|
4 * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved.
|
|
5 * See also 'README'
|
|
6 *
|
|
7 * slighlty optimized for machines without autoincrement/decrement.
|
|
8 * The performance is highly compiler dependend. Maybe
|
|
9 * the decode.c version for 'normal' processor may be faster
|
|
10 * even for Intel processors.
|
|
11 */
|
|
12
|
|
13 #include <stdlib.h>
|
|
14 #include <math.h>
|
|
15 #include <string.h>
|
|
16
|
|
17 #include "mpg123_sdlsound.h"
|
|
18 #include "mpglib_sdlsound.h"
|
|
19
|
|
20 extern struct mpstr *gmp;
|
|
21
|
|
22 /* old WRITE_SAMPLE */
|
|
23 #define WRITE_SAMPLE(samples,sum,clip) \
|
|
24 if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \
|
|
25 else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \
|
|
26 else { *(samples) = sum; }
|
|
27
|
|
28 int synth_1to1_mono(real *bandPtr,unsigned char *samples,int *pnt)
|
|
29 {
|
|
30 short samples_tmp[64];
|
|
31 short *tmp1 = samples_tmp;
|
|
32 int i,ret;
|
|
33 int pnt1 = 0;
|
|
34
|
|
35 ret = synth_1to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1);
|
|
36 samples += *pnt;
|
|
37
|
|
38 for(i=0;i<32;i++) {
|
|
39 *( (short *) samples) = *tmp1;
|
|
40 samples += 2;
|
|
41 tmp1 += 2;
|
|
42 }
|
|
43 *pnt += 64;
|
|
44
|
|
45 return ret;
|
|
46 }
|
|
47
|
|
48
|
|
49 int synth_1to1(real *bandPtr,int channel,unsigned char *out,int *pnt)
|
|
50 {
|
|
51 static const int step = 2;
|
|
52 int bo;
|
|
53 short *samples = (short *) (out + *pnt);
|
|
54
|
|
55 real *b0,(*buf)[0x110];
|
|
56 int clip = 0;
|
|
57 int bo1;
|
|
58
|
|
59 bo = gmp->synth_bo;
|
|
60
|
|
61 if(!channel) {
|
|
62 bo--;
|
|
63 bo &= 0xf;
|
|
64 buf = gmp->synth_buffs[0];
|
|
65 }
|
|
66 else {
|
|
67 samples++;
|
|
68 buf = gmp->synth_buffs[1];
|
|
69 }
|
|
70
|
|
71 if(bo & 0x1) {
|
|
72 b0 = buf[0];
|
|
73 bo1 = bo;
|
|
74 dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr);
|
|
75 }
|
|
76 else {
|
|
77 b0 = buf[1];
|
|
78 bo1 = bo+1;
|
|
79 dct64(buf[0]+bo,buf[1]+bo+1,bandPtr);
|
|
80 }
|
|
81
|
|
82 gmp->synth_bo = bo;
|
|
83
|
|
84 {
|
|
85 register int j;
|
|
86 real *window = decwin + 16 - bo1;
|
|
87
|
|
88 for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step)
|
|
89 {
|
|
90 real sum;
|
|
91 sum = window[0x0] * b0[0x0];
|
|
92 sum -= window[0x1] * b0[0x1];
|
|
93 sum += window[0x2] * b0[0x2];
|
|
94 sum -= window[0x3] * b0[0x3];
|
|
95 sum += window[0x4] * b0[0x4];
|
|
96 sum -= window[0x5] * b0[0x5];
|
|
97 sum += window[0x6] * b0[0x6];
|
|
98 sum -= window[0x7] * b0[0x7];
|
|
99 sum += window[0x8] * b0[0x8];
|
|
100 sum -= window[0x9] * b0[0x9];
|
|
101 sum += window[0xA] * b0[0xA];
|
|
102 sum -= window[0xB] * b0[0xB];
|
|
103 sum += window[0xC] * b0[0xC];
|
|
104 sum -= window[0xD] * b0[0xD];
|
|
105 sum += window[0xE] * b0[0xE];
|
|
106 sum -= window[0xF] * b0[0xF];
|
|
107
|
|
108 WRITE_SAMPLE(samples,sum,clip);
|
|
109 }
|
|
110
|
|
111 {
|
|
112 real sum;
|
|
113 sum = window[0x0] * b0[0x0];
|
|
114 sum += window[0x2] * b0[0x2];
|
|
115 sum += window[0x4] * b0[0x4];
|
|
116 sum += window[0x6] * b0[0x6];
|
|
117 sum += window[0x8] * b0[0x8];
|
|
118 sum += window[0xA] * b0[0xA];
|
|
119 sum += window[0xC] * b0[0xC];
|
|
120 sum += window[0xE] * b0[0xE];
|
|
121 WRITE_SAMPLE(samples,sum,clip);
|
|
122 b0-=0x10,window-=0x20,samples+=step;
|
|
123 }
|
|
124 window += bo1<<1;
|
|
125
|
|
126 for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step)
|
|
127 {
|
|
128 real sum;
|
|
129 sum = -window[-0x1] * b0[0x0];
|
|
130 sum -= window[-0x2] * b0[0x1];
|
|
131 sum -= window[-0x3] * b0[0x2];
|
|
132 sum -= window[-0x4] * b0[0x3];
|
|
133 sum -= window[-0x5] * b0[0x4];
|
|
134 sum -= window[-0x6] * b0[0x5];
|
|
135 sum -= window[-0x7] * b0[0x6];
|
|
136 sum -= window[-0x8] * b0[0x7];
|
|
137 sum -= window[-0x9] * b0[0x8];
|
|
138 sum -= window[-0xA] * b0[0x9];
|
|
139 sum -= window[-0xB] * b0[0xA];
|
|
140 sum -= window[-0xC] * b0[0xB];
|
|
141 sum -= window[-0xD] * b0[0xC];
|
|
142 sum -= window[-0xE] * b0[0xD];
|
|
143 sum -= window[-0xF] * b0[0xE];
|
|
144 sum -= window[-0x0] * b0[0xF];
|
|
145
|
|
146 WRITE_SAMPLE(samples,sum,clip);
|
|
147 }
|
|
148 }
|
|
149 *pnt += 128;
|
|
150
|
|
151 return clip;
|
|
152 }
|
|
153
|