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-rw-r--r--mp3lib/layer2.c295
1 files changed, 295 insertions, 0 deletions
diff --git a/mp3lib/layer2.c b/mp3lib/layer2.c
new file mode 100644
index 0000000000..b8d7d12df7
--- /dev/null
+++ b/mp3lib/layer2.c
@@ -0,0 +1,295 @@
+/*
+ * Mpeg Layer-2 audio decoder
+ * --------------------------
+ * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README'
+ *
+ */
+
+//#include "mpg123.h"
+#include "l2tables.h"
+
+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 */
+
+static real muls[27][64]; /* also used by layer 1 */
+
+static 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 };
+
+ 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];
+ }
+ }
+
+ for(k=0;k<27;k++)
+ {
+ double m=mulmul[k];
+ table = muls[k];
+ for(j=3,i=0;i<63;i++,j--)
+ *table++ = m * pow(2.0,(double) j / 3.0);
+ *table++ = 0.0;
+ }
+}
+
+
+static 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;
+
+ 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);
+ }
+
+ 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;
+ }
+
+}
+
+static 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;
+
+ 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;
+ }
+ }
+
+ 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 !!
+*/
+ }
+
+ if(sblimit > (fr->down_sample_sblimit) )
+ sblimit = fr->down_sample_sblimit;
+
+ 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;
+
+}
+
+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 } } };
+
+ 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 };
+
+ if(fr->lsf)
+ table = 4;
+ else
+ table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index];
+ sblim = sblims[table];
+
+ fr->alloc = tables[table];
+ fr->II_sblimit = sblim;
+}
+
+
+int do_layer2(struct frame *fr,int outmode)
+{
+ 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;
+
+ II_select_table(fr);
+ fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
+ (fr->mode_ext<<2)+4 : fr->II_sblimit;
+
+ if(stereo == 1 || single == 3)
+ single = 0;
+
+ II_step_one(bit_alloc, scale, fr);
+
+ 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);
+ }
+
+// if(pcm_point >= audiobufsize) audio_flush(outmode,ai);
+ }
+ }
+
+ return clip;
+}
+
+
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