0,0 → 1,306 |
/* |
layer2.c: the layer 2 decoder, root of mpg123 |
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copyright 1994-2006 by the mpg123 project - free software under the terms of the LGPL 2.1 |
see COPYING and AUTHORS files in distribution or http://mpg123.de |
initially written by Michael Hipp |
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mpg123 started as mp2 decoder a long time ago... |
*/ |
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#include "mpg123.h" |
#include "l2tables.h" |
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static int grp_3tab[32 * 3] = { 0, }; /* used: 27 */ |
static int grp_5tab[128 * 3] = { 0, }; /* used: 125 */ |
static int grp_9tab[1024 * 3] = { 0, }; /* used: 729 */ |
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real muls[27][64]; /* also used by layer 1 */ |
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void init_layer2(void) |
{ |
static double mulmul[27] = { |
0.0 , -2.0/3.0 , 2.0/3.0 , |
2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 , |
2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 , |
2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 , |
-4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 , |
-8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0 }; |
static int base[3][9] = { |
{ 1 , 0, 2 , } , |
{ 17, 18, 0 , 19, 20 , } , |
{ 21, 1, 22, 23, 0, 24, 25, 2, 26 } }; |
int i,j,k,l,len; |
real *table; |
static int tablen[3] = { 3 , 5 , 9 }; |
static int *itable,*tables[3] = { grp_3tab , grp_5tab , grp_9tab }; |
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for(i=0;i<3;i++) |
{ |
itable = tables[i]; |
len = tablen[i]; |
for(j=0;j<len;j++) |
for(k=0;k<len;k++) |
for(l=0;l<len;l++) |
{ |
*itable++ = base[i][l]; |
*itable++ = base[i][k]; |
*itable++ = base[i][j]; |
} |
} |
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for(k=0;k<27;k++) |
{ |
double m=mulmul[k]; |
table = muls[k]; |
#ifdef USE_MMX |
if(!param.down_sample) |
for(j=3,i=0;i<63;i++,j--) |
*table++ = 16384 * m * pow(2.0,(double) j / 3.0); |
else |
#endif |
for(j=3,i=0;i<63;i++,j--) |
*table++ = m * pow_test(2.0,(double) j / 3.0); |
*table++ = 0.0; |
} |
} |
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void II_step_one(unsigned int *bit_alloc,int *scale,struct frame *fr) |
{ |
int stereo = fr->stereo-1; |
int sblimit = fr->II_sblimit; |
int jsbound = fr->jsbound; |
int sblimit2 = fr->II_sblimit<<stereo; |
struct al_table *alloc1 = fr->alloc; |
int i; |
static unsigned int scfsi_buf[64]; |
unsigned int *scfsi,*bita; |
int sc,step; |
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bita = bit_alloc; |
if(stereo) |
{ |
for (i=jsbound;i;i--,alloc1+=(1<<step)) |
{ |
*bita++ = (char) getbits(step=alloc1->bits); |
*bita++ = (char) getbits(step); |
} |
for (i=sblimit-jsbound;i;i--,alloc1+=(1<<step)) |
{ |
bita[0] = (char) getbits(step=alloc1->bits); |
bita[1] = bita[0]; |
bita+=2; |
} |
bita = bit_alloc; |
scfsi=scfsi_buf; |
for (i=sblimit2;i;i--) |
if (*bita++) |
*scfsi++ = (char) getbits_fast(2); |
} |
else /* mono */ |
{ |
for (i=sblimit;i;i--,alloc1+=(1<<step)) |
*bita++ = (char) getbits(step=alloc1->bits); |
bita = bit_alloc; |
scfsi=scfsi_buf; |
for (i=sblimit;i;i--) |
if (*bita++) |
*scfsi++ = (char) getbits_fast(2); |
} |
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bita = bit_alloc; |
scfsi=scfsi_buf; |
for (i=sblimit2;i;i--) |
if (*bita++) |
switch (*scfsi++) |
{ |
case 0: |
*scale++ = getbits_fast(6); |
*scale++ = getbits_fast(6); |
*scale++ = getbits_fast(6); |
break; |
case 1 : |
*scale++ = sc = getbits_fast(6); |
*scale++ = sc; |
*scale++ = getbits_fast(6); |
break; |
case 2: |
*scale++ = sc = getbits_fast(6); |
*scale++ = sc; |
*scale++ = sc; |
break; |
default: /* case 3 */ |
*scale++ = getbits_fast(6); |
*scale++ = sc = getbits_fast(6); |
*scale++ = sc; |
break; |
} |
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} |
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void II_step_two(unsigned int *bit_alloc,real fraction[2][4][SBLIMIT],int *scale,struct frame *fr,int x1) |
{ |
int i,j,k,ba; |
int stereo = fr->stereo; |
int sblimit = fr->II_sblimit; |
int jsbound = fr->jsbound; |
struct al_table *alloc2,*alloc1 = fr->alloc; |
unsigned int *bita=bit_alloc; |
int d1,step; |
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for (i=0;i<jsbound;i++,alloc1+=(1<<step)) |
{ |
step = alloc1->bits; |
for (j=0;j<stereo;j++) |
{ |
if ( (ba=*bita++) ) |
{ |
k=(alloc2 = alloc1+ba)->bits; |
if( (d1=alloc2->d) < 0) |
{ |
real cm=muls[k][scale[x1]]; |
fraction[j][0][i] = ((real) ((int)getbits(k) + d1)) * cm; |
fraction[j][1][i] = ((real) ((int)getbits(k) + d1)) * cm; |
fraction[j][2][i] = ((real) ((int)getbits(k) + d1)) * cm; |
} |
else |
{ |
static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab }; |
unsigned int idx,*tab,m=scale[x1]; |
idx = (unsigned int) getbits(k); |
tab = (unsigned int *) (table[d1] + idx + idx + idx); |
fraction[j][0][i] = muls[*tab++][m]; |
fraction[j][1][i] = muls[*tab++][m]; |
fraction[j][2][i] = muls[*tab][m]; |
} |
scale+=3; |
} |
else |
fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0; |
} |
} |
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for (i=jsbound;i<sblimit;i++,alloc1+=(1<<step)) |
{ |
step = alloc1->bits; |
bita++; /* channel 1 and channel 2 bitalloc are the same */ |
if ( (ba=*bita++) ) |
{ |
k=(alloc2 = alloc1+ba)->bits; |
if( (d1=alloc2->d) < 0) |
{ |
real cm; |
cm=muls[k][scale[x1+3]]; |
fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(k) + d1) ) * cm; |
fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(k) + d1) ) * cm; |
fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(k) + d1) ) * cm; |
cm=muls[k][scale[x1]]; |
fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm; |
} |
else |
{ |
static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab }; |
unsigned int idx,*tab,m1,m2; |
m1 = scale[x1]; m2 = scale[x1+3]; |
idx = (unsigned int) getbits(k); |
tab = (unsigned int *) (table[d1] + idx + idx + idx); |
fraction[0][0][i] = muls[*tab][m1]; fraction[1][0][i] = muls[*tab++][m2]; |
fraction[0][1][i] = muls[*tab][m1]; fraction[1][1][i] = muls[*tab++][m2]; |
fraction[0][2][i] = muls[*tab][m1]; fraction[1][2][i] = muls[*tab][m2]; |
} |
scale+=6; |
} |
else { |
fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] = |
fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0; |
} |
/* |
should we use individual scalefac for channel 2 or |
is the current way the right one , where we just copy channel 1 to |
channel 2 ?? |
The current 'strange' thing is, that we throw away the scalefac |
values for the second channel ...!! |
-> changed .. now we use the scalefac values of channel one !! |
*/ |
} |
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if(sblimit > (fr->down_sample_sblimit) ) |
sblimit = fr->down_sample_sblimit; |
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for(i=sblimit;i<SBLIMIT;i++) |
for (j=0;j<stereo;j++) |
fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0; |
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} |
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static void II_select_table(struct frame *fr) |
{ |
static int translate[3][2][16] = |
{ { { 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0 } , |
{ 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0 } } , |
{ { 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0 } , |
{ 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0 } } , |
{ { 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0 } , |
{ 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0 } } }; |
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int table,sblim; |
static struct al_table *tables[5] = |
{ alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 }; |
static int sblims[5] = { 27 , 30 , 8, 12 , 30 }; |
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if(fr->sampling_frequency >= 3) /* Or equivalent: (fr->lsf == 1) */ |
table = 4; |
else |
table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index]; |
sblim = sblims[table]; |
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fr->alloc = tables[table]; |
fr->II_sblimit = sblim; |
} |
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int do_layer2(struct frame *fr,byte *pcm_sample,int *pcm_point) |
{ |
int clip=0; |
int i,j; |
int stereo = fr->stereo; |
real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */ |
unsigned int bit_alloc[64]; |
int scale[192]; |
int single = fr->single; |
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II_select_table(fr); |
fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? |
(fr->mode_ext<<2)+4 : fr->II_sblimit; |
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if (fr->jsbound > fr->II_sblimit) { |
fr->jsbound=fr->II_sblimit; |
} |
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if(stereo == 1 || single == 3) |
single = 0; |
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II_step_one(bit_alloc, scale, fr); |
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for (i=0;i<SCALE_BLOCK;i++) |
{ |
II_step_two(bit_alloc,fraction,scale,fr,i>>2); |
for (j=0;j<3;j++) |
{ |
if(single >= 0) |
{ |
clip += (fr->synth_mono) (fraction[single][j],pcm_sample,pcm_point); |
} |
else { |
int p1=*pcm_point; |
clip += (fr->synth) (fraction[0][j],0,pcm_sample, &p1); |
clip += (fr->synth) (fraction[1][j],1,pcm_sample,pcm_point); |
} |
} |
} |
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return clip; |
} |
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