lib/mapping0.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
   4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   7  *                                                                  *
   8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
   9  * by the XIPHOPHORUS Company http://www.xiph.org/                  *
  10  *                                                                  *
  11  ********************************************************************
  12
  13  function: channel mapping 0 implementation
  14  last mod: $Id: mapping0.c,v 1.44 2002/01/22 11:59:00 xiphmont Exp $
  15
  16  ********************************************************************/
  17
  18 #include <stdlib.h>
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <math.h>
  22 #include <ogg/ogg.h>
  23 #include "vorbis/codec.h"
  24 #include "codec_internal.h"
  25 #include "codebook.h"
  26 #include "window.h"
  27 #include "registry.h"
  28 #include "psy.h"
  29 #include "misc.h"
  30
  31 /* simplistic, wasteful way of doing this (unique lookup for each
  32    mode/submapping); there should be a central repository for
  33    identical lookups.  That will require minor work, so I'm putting it
  34    off as low priority.
  35
  36    Why a lookup for each backend in a given mode?  Because the
  37    blocksize is set by the mode, and low backend lookups may require
  38    parameters from other areas of the mode/mapping */
  39
  40 extern int analysis_noisy;
  41
  42 typedef struct {
  43   drft_lookup fft_look;
  44   vorbis_info_mode *mode;
  45   vorbis_info_mapping0 *map;
  46
  47   vorbis_look_time **time_look;
  48   vorbis_look_floor **floor_look;
  49
  50   vorbis_look_residue **residue_look;
  51   vorbis_look_psy *psy_look[2];
  52
  53   vorbis_func_time **time_func;
  54   vorbis_func_floor **floor_func;
  55   vorbis_func_residue **residue_func;
  56
  57   int ch;
  58   long lastframe; /* if a different mode is called, we need to
  59                      invalidate decay */
  60 } vorbis_look_mapping0;
  61
  62 static vorbis_info_mapping *mapping0_copy_info(vorbis_info_mapping *vm){
  63   vorbis_info_mapping0 *info=(vorbis_info_mapping0 *)vm;
  64   vorbis_info_mapping0 *ret=_ogg_malloc(sizeof(*ret));
  65   memcpy(ret,info,sizeof(*ret));
  66   return(ret);
  67 }
  68
  69 static void mapping0_free_info(vorbis_info_mapping *i){
  70   vorbis_info_mapping0 *info=(vorbis_info_mapping0 *)i;
  71   if(info){
  72     memset(info,0,sizeof(*info));
  73     _ogg_free(info);
  74   }
  75 }
  76
  77 static void mapping0_free_look(vorbis_look_mapping *look){
  78   int i;
  79   vorbis_look_mapping0 *l=(vorbis_look_mapping0 *)look;
  80   if(l){
  81     drft_clear(&l->fft_look);
  82
  83     for(i=0;i<l->map->submaps;i++){
  84       l->time_func[i]->free_look(l->time_look[i]);
  85       l->floor_func[i]->free_look(l->floor_look[i]);
  86       l->residue_func[i]->free_look(l->residue_look[i]);
  87     }
  88     if(l->psy_look[1] && l->psy_look[1]!=l->psy_look[0]){
  89       _vp_psy_clear(l->psy_look[1]);
  90       _ogg_free(l->psy_look[1]);
  91     }
  92     if(l->psy_look[0]){
  93       _vp_psy_clear(l->psy_look[0]);
  94       _ogg_free(l->psy_look[0]);
  95     }
  96     _ogg_free(l->time_func);
  97     _ogg_free(l->floor_func);
  98     _ogg_free(l->residue_func);
  99     _ogg_free(l->time_look);
 100     _ogg_free(l->floor_look);
 101     _ogg_free(l->residue_look);
 102     memset(l,0,sizeof(*l));
 103     _ogg_free(l);
 104   }
 105 }
 106
 107 static vorbis_look_mapping *mapping0_look(vorbis_dsp_state *vd,vorbis_info_mode *vm,
 108                           vorbis_info_mapping *m){
 109   int i;
 110   vorbis_info          *vi=vd->vi;
 111   codec_setup_info     *ci=vi->codec_setup;
 112   vorbis_look_mapping0 *look=_ogg_calloc(1,sizeof(*look));
 113   vorbis_info_mapping0 *info=look->map=(vorbis_info_mapping0 *)m;
 114   look->mode=vm;
 115
 116   look->time_look=_ogg_calloc(info->submaps,sizeof(*look->time_look));
 117   look->floor_look=_ogg_calloc(info->submaps,sizeof(*look->floor_look));
 118
 119   look->residue_look=_ogg_calloc(info->submaps,sizeof(*look->residue_look));
 120
 121   look->time_func=_ogg_calloc(info->submaps,sizeof(*look->time_func));
 122   look->floor_func=_ogg_calloc(info->submaps,sizeof(*look->floor_func));
 123   look->residue_func=_ogg_calloc(info->submaps,sizeof(*look->residue_func));
 124
 125   for(i=0;i<info->submaps;i++){
 126     int timenum=info->timesubmap[i];
 127     int floornum=info->floorsubmap[i];
 128     int resnum=info->residuesubmap[i];
 129
 130     look->time_func[i]=_time_P[ci->time_type[timenum]];
 131     look->time_look[i]=look->time_func[i]->
 132       look(vd,vm,ci->time_param[timenum]);
 133     look->floor_func[i]=_floor_P[ci->floor_type[floornum]];
 134     look->floor_look[i]=look->floor_func[i]->
 135       look(vd,vm,ci->floor_param[floornum]);
 136     look->residue_func[i]=_residue_P[ci->residue_type[resnum]];
 137     look->residue_look[i]=look->residue_func[i]->
 138       look(vd,vm,ci->residue_param[resnum]);
 139
 140   }
 141   if(ci->psys && vd->analysisp){
 142     if(info->psy[0] != info->psy[1]){
 143
 144       int psynum=info->psy[0];
 145       look->psy_look[0]=_ogg_calloc(1,sizeof(*look->psy_look[0]));
 146       _vp_psy_init(look->psy_look[0],ci->psy_param[psynum],
 147                    &ci->psy_g_param,
 148                    ci->blocksizes[vm->blockflag]/2,vi->rate);
 149
 150       psynum=info->psy[1];
 151       look->psy_look[1]=_ogg_calloc(1,sizeof(*look->psy_look[1]));
 152       _vp_psy_init(look->psy_look[1],ci->psy_param[psynum],
 153                    &ci->psy_g_param,
 154                    ci->blocksizes[vm->blockflag]/2,vi->rate);
 155     }else{
 156
 157       int psynum=info->psy[0];
 158       look->psy_look[0]=_ogg_calloc(1,sizeof(*look->psy_look[0]));
 159       look->psy_look[1]=look->psy_look[0];
 160       _vp_psy_init(look->psy_look[0],ci->psy_param[psynum],
 161                    &ci->psy_g_param,
 162                    ci->blocksizes[vm->blockflag]/2,vi->rate);
 163
 164     }
 165   }
 166
 167   look->ch=vi->channels;
 168
 169   if(vd->analysisp)drft_init(&look->fft_look,ci->blocksizes[vm->blockflag]);
 170   return(look);
 171 }
 172
 173 static int ilog2(unsigned int v){
 174   int ret=0;
 175   while(v>1){
 176     ret++;
 177     v>>=1;
 178   }
 179   return(ret);
 180 }
 181
 182 static void mapping0_pack(vorbis_info *vi,vorbis_info_mapping *vm,
 183                           oggpack_buffer *opb){
 184   int i;
 185   vorbis_info_mapping0 *info=(vorbis_info_mapping0 *)vm;
 186
 187   /* another 'we meant to do it this way' hack...  up to beta 4, we
 188      packed 4 binary zeros here to signify one submapping in use.  We
 189      now redefine that to mean four bitflags that indicate use of
 190      deeper features; bit0:submappings, bit1:coupling,
 191      bit2,3:reserved. This is backward compatable with all actual uses
 192      of the beta code. */
 193
 194   if(info->submaps>1){
 195     oggpack_write(opb,1,1);
 196     oggpack_write(opb,info->submaps-1,4);
 197   }else
 198     oggpack_write(opb,0,1);
 199
 200   if(info->coupling_steps>0){
 201     oggpack_write(opb,1,1);
 202     oggpack_write(opb,info->coupling_steps-1,8);
 203
 204     for(i=0;i<info->coupling_steps;i++){
 205       oggpack_write(opb,info->coupling_mag[i],ilog2(vi->channels));
 206       oggpack_write(opb,info->coupling_ang[i],ilog2(vi->channels));
 207     }
 208   }else
 209     oggpack_write(opb,0,1);
 210
 211   oggpack_write(opb,0,2); /* 2,3:reserved */
 212
 213   /* we don't write the channel submappings if we only have one... */
 214   if(info->submaps>1){
 215     for(i=0;i<vi->channels;i++)
 216       oggpack_write(opb,info->chmuxlist[i],4);
 217   }
 218   for(i=0;i<info->submaps;i++){
 219     oggpack_write(opb,info->timesubmap[i],8);
 220     oggpack_write(opb,info->floorsubmap[i],8);
 221     oggpack_write(opb,info->residuesubmap[i],8);
 222   }
 223 }
 224
 225 /* also responsible for range checking */
 226 static vorbis_info_mapping *mapping0_unpack(vorbis_info *vi,oggpack_buffer *opb){
 227   int i;
 228   vorbis_info_mapping0 *info=_ogg_calloc(1,sizeof(*info));
 229   codec_setup_info     *ci=vi->codec_setup;
 230   memset(info,0,sizeof(*info));
 231
 232   if(oggpack_read(opb,1))
 233     info->submaps=oggpack_read(opb,4)+1;
 234   else
 235     info->submaps=1;
 236
 237   if(oggpack_read(opb,1)){
 238     info->coupling_steps=oggpack_read(opb,8)+1;
 239
 240     for(i=0;i<info->coupling_steps;i++){
 241       int testM=info->coupling_mag[i]=oggpack_read(opb,ilog2(vi->channels));
 242       int testA=info->coupling_ang[i]=oggpack_read(opb,ilog2(vi->channels));
 243
 244       if(testM<0 ||
 245          testA<0 ||
 246          testM==testA ||
 247          testM>=vi->channels ||
 248          testA>=vi->channels) goto err_out;
 249     }
 250
 251   }
 252
 253   if(oggpack_read(opb,2)>0)goto err_out; /* 2,3:reserved */
 254
 255   if(info->submaps>1){
 256     for(i=0;i<vi->channels;i++){
 257       info->chmuxlist[i]=oggpack_read(opb,4);
 258       if(info->chmuxlist[i]>=info->submaps)goto err_out;
 259     }
 260   }
 261   for(i=0;i<info->submaps;i++){
 262     info->timesubmap[i]=oggpack_read(opb,8);
 263     if(info->timesubmap[i]>=ci->times)goto err_out;
 264     info->floorsubmap[i]=oggpack_read(opb,8);
 265     if(info->floorsubmap[i]>=ci->floors)goto err_out;
 266     info->residuesubmap[i]=oggpack_read(opb,8);
 267     if(info->residuesubmap[i]>=ci->residues)goto err_out;
 268   }
 269
 270   return info;
 271
 272  err_out:
 273   mapping0_free_info(info);
 274   return(NULL);
 275 }
 276
 277 #include "os.h"
 278 #include "lpc.h"
 279 #include "lsp.h"
 280 #include "envelope.h"
 281 #include "mdct.h"
 282 #include "psy.h"
 283 #include "scales.h"
 284
 285 /* no time mapping implementation for now */
 286 static long seq=0;
 287 static int mapping0_forward(vorbis_block *vb,vorbis_look_mapping *l){
 288   vorbis_dsp_state      *vd=vb->vd;
 289   vorbis_info           *vi=vd->vi;
 290   codec_setup_info      *ci=vi->codec_setup;
 291   backend_lookup_state  *b=vb->vd->backend_state;
 292   bitrate_manager_state *bm=&b->bms;
 293   vorbis_look_mapping0  *look=(vorbis_look_mapping0 *)l;
 294   vorbis_info_mapping0  *info=look->map;
 295   vorbis_info_mode      *mode=look->mode;
 296   vorbis_block_internal *vbi=(vorbis_block_internal *)vb->internal;
 297   int                    n=vb->pcmend;
 298   int i,j;
 299   int   *nonzero=alloca(sizeof(*nonzero)*vi->channels);
 300
 301   float *work=_vorbis_block_alloc(vb,n*sizeof(*work));
 302
 303   float global_ampmax=vbi->ampmax;
 304   float *local_ampmax=alloca(sizeof(*local_ampmax)*vi->channels);
 305   int blocktype=vbi->blocktype;
 306
 307   /* we differentiate between short and long block types to help the
 308      masking engine; the window shapes also matter.
 309      impulse block (a short block in which an impulse occurs)
 310      padding block (a short block that pads between a transitional
 311           long block and an impulse block, or vice versa)
 312      transition block (the wqeird one; a long block with the transition
 313           window; affects bass/midrange response and that must be
 314           accounted for in masking)
 315      long block (run of the mill long block)
 316   */
 317
 318   for(i=0;i<vi->channels;i++){
 319     float scale=4.f/n;
 320     float scale_dB;
 321
 322     /* the following makes things clearer to *me* anyway */
 323     float *pcm     =vb->pcm[i];
 324     float *fft     =work;
 325     float *logfft  =pcm+n/2;
 326
 327     /*float *res     =pcm;
 328     float *mdct    =pcm;
 329     float *codedflr=pcm+n/2;
 330     float *logmax  =work;
 331     float *logmask =work+n/2;*/
 332
 333     scale_dB=todB(&scale);
 334     _analysis_output("pcm",seq+i,pcm,n,0,0);
 335
 336     /* window the PCM data */
 337     _vorbis_apply_window(pcm,b->window,ci->blocksizes,vb->lW,vb->W,vb->nW);
 338     memcpy(fft,pcm,sizeof(*fft)*n);
 339
 340     /*_analysis_output("windowed",seq+i,pcm,n,0,0);*/
 341
 342     /* transform the PCM data */
 343     /* only MDCT right now.... */
 344     mdct_forward(b->transform[vb->W][0],pcm,pcm);
 345
 346     /* FFT yields more accurate tonal estimation (not phase sensitive) */
 347     drft_forward(&look->fft_look,fft);
 348     fft[0]*=scale;
 349     logfft[0]=todB(fft);
 350     local_ampmax[i]=logfft[0];
 351     for(j=1;j<n-1;j+=2){
 352       float temp=fft[j]*fft[j]+fft[j+1]*fft[j+1];
 353       temp=logfft[(j+1)>>1]=scale_dB+.5f*todB(&temp);
 354       if(temp>local_ampmax[i])local_ampmax[i]=temp;
 355     }
 356
 357     if(local_ampmax[i]>0.f)local_ampmax[i]=0.f;
 358     if(local_ampmax[i]>global_ampmax)global_ampmax=local_ampmax[i];
 359
 360     _analysis_output("fft",seq+i,logfft,n/2,1,0);
 361   }
 362
 363   for(i=0;i<vi->channels;i++){
 364     int submap=info->chmuxlist[i];
 365
 366     /* the following makes things clearer to *me* anyway */
 367     float *mdct    =vb->pcm[i];
 368     float *res     =mdct;
 369     float *codedflr=mdct+n/2;
 370     float *logfft  =mdct+n/2;
 371
 372     float *logmdct =work;
 373     float *logmax  =mdct+n/2;
 374     float *logmask =work+n/2;
 375
 376     for(j=0;j<n/2;j++)
 377       logmdct[j]=todB(mdct+j);
 378     _analysis_output("mdct",seq+i,logmdct,n/2,1,0);
 379
 380
 381     /* perform psychoacoustics; do masking */
 382     _vp_compute_mask(look->psy_look[blocktype],
 383                      logfft, /* -> logmax */
 384                      logmdct,
 385                      logmask,
 386                      global_ampmax,
 387                      local_ampmax[i],
 388                      bm->avgnoise);
 389
 390     _analysis_output("mask",seq+i,logmask,n/2,1,0);
 391     /* perform floor encoding */
 392     nonzero[i]=look->floor_func[submap]->
 393       forward(vb,look->floor_look[submap],
 394               mdct,
 395               logmdct,
 396               logmask,
 397               logmax,
 398
 399               codedflr);
 400
 401
 402     _vp_remove_floor(look->psy_look[blocktype],
 403                      mdct,
 404                      codedflr,
 405                      res);
 406
 407     /*for(j=0;j<n/2;j++)
 408       if(fabs(res[j])>1200){
 409         analysis_noisy=1;
 410         fprintf(stderr,"%ld ",seq+i);
 411         }*/
 412
 413     _analysis_output("codedflr",seq+i,codedflr,n/2,1,1);
 414
 415   }
 416
 417   vbi->ampmax=global_ampmax;
 418
 419   /* partition based prequantization and channel coupling */
 420   /* Steps in prequant and coupling:
 421
 422      classify by |mag| across all pcm vectors
 423
 424      down-couple/down-quantize from perfect residue ->  quantized vector
 425
 426      do{
 427         encode quantized vector; add encoded values to 'so-far' vector
 428         more? [not yet at bitrate/not yet at target]
 429           yes{
 430               down-couple/down-quantize from perfect-'so-far' ->
 431                 quantized vector; when subtracting coupling,
 432                 account for +/- out-of-phase component
 433           }no{
 434               break
 435           }
 436      }
 437      done.
 438
 439      quantization in each iteration is done (after circular normalization
 440      in coupling) using a by-iteration quantization granule value.
 441   */
 442
 443   {
 444     float  **pcm=vb->pcm;
 445     float  **quantized=alloca(sizeof(*quantized)*vi->channels);
 446     float  **sofar=alloca(sizeof(*sofar)*vi->channels);
 447
 448     long  ***classifications=alloca(sizeof(*classifications)*info->submaps);
 449     float ***qbundle=alloca(sizeof(*qbundle)*info->submaps);
 450     float ***pcmbundle=alloca(sizeof(*pcmbundle)*info->submaps);
 451     float ***sobundle=alloca(sizeof(*sobundle)*info->submaps);
 452     int    **zerobundle=alloca(sizeof(*zerobundle)*info->submaps);
 453     int     *chbundle=alloca(sizeof(*chbundle)*info->submaps);
 454     int      chcounter=0;
 455
 456     /* play a little loose with this abstraction */
 457     int   quant_passes=ci->coupling_passes;
 458
 459     for(i=0;i<vi->channels;i++){
 460       quantized[i]=_vorbis_block_alloc(vb,n*sizeof(*sofar[i]));
 461       sofar[i]=quantized[i]+n/2;
 462       memset(sofar[i],0,sizeof(*sofar[i])*n/2);
 463     }
 464
 465     qbundle[0]=alloca(sizeof(*qbundle[0])*vi->channels);
 466     pcmbundle[0]=alloca(sizeof(*pcmbundle[0])*vi->channels);
 467     sobundle[0]=alloca(sizeof(*sobundle[0])*vi->channels);
 468     zerobundle[0]=alloca(sizeof(*zerobundle[0])*vi->channels);
 469
 470     /* initial down-quantized coupling */
 471
 472     if(info->coupling_steps==0){
 473       /* this assumes all or nothing coupling right now.  it should pass
 474          through any channels left uncoupled, but it doesn't do that now */
 475       for(i=0;i<vi->channels;i++){
 476         float *lpcm=pcm[i];
 477         float *lqua=quantized[i];
 478         for(j=0;j<n/2;j++)
 479           lqua[j]=lpcm[j];
 480       }
 481     }else{
 482       _vp_quantize_couple(look->psy_look[blocktype],
 483                           info,
 484                           pcm,
 485                           sofar,
 486                           quantized,
 487                           nonzero,
 488                           0);
 489     }
 490
 491     for(i=0;i<vi->channels;i++)
 492       _analysis_output("quant",seq+i,quantized[i],n/2,1,0);
 493
 494
 495     /* classify, by submap */
 496
 497     for(i=0;i<info->submaps;i++){
 498       int ch_in_bundle=0;
 499       qbundle[i]=qbundle[0]+chcounter;
 500       sobundle[i]=sobundle[0]+chcounter;
 501       zerobundle[i]=zerobundle[0]+chcounter;
 502
 503       for(j=0;j<vi->channels;j++){
 504         if(info->chmuxlist[j]==i){
 505           if(nonzero[j])
 506             zerobundle[i][ch_in_bundle]=1;
 507           else
 508             zerobundle[i][ch_in_bundle]=0;
 509           qbundle[i][ch_in_bundle]=quantized[j];
 510           pcmbundle[i][ch_in_bundle]=pcm[j];
 511           sobundle[i][ch_in_bundle++]=sofar[j];
 512         }
 513       }
 514       chbundle[i]=ch_in_bundle;
 515       chcounter+=ch_in_bundle;
 516
 517       classifications[i]=look->residue_func[i]->
 518         class(vb,look->residue_look[i],pcmbundle[i],zerobundle[i],chbundle[i]);
 519     }
 520
 521     /* actual encoding loop; we pack all the iterations to collect
 522        management data */
 523
 524     for(i=0;i<quant_passes;){
 525
 526       /* perform residue encoding of this pass's quantized residue
 527          vector, according residue mapping */
 528
 529       for(j=0;j<info->submaps;j++){
 530         look->residue_func[j]->
 531           forward(vb,look->residue_look[j],
 532                   qbundle[j],sobundle[j],zerobundle[j],chbundle[j],
 533                   i,classifications[j],vbi->packet_markers);
 534
 535       }
 536       i++;
 537
 538       if(i<quant_passes){
 539         /* down-couple/down-quantize from perfect-'so-far' ->
 540          new quantized vector */
 541         if(info->coupling_steps==0){
 542           /* this assumes all or nothing coupling right now.  it should pass
 543              through any channels left uncoupled, but it doesn't do that now */
 544           int k;
 545           for(k=0;k<vi->channels;k++){
 546             float *lpcm=pcm[k];
 547             float *lsof=sofar[k];
 548             float *lqua=quantized[k];
 549             for(j=0;j<n/2;j++)
 550               lqua[j]=lpcm[j]-lsof[j];
 551           }
 552         }else{
 553
 554           _vp_quantize_couple(look->psy_look[blocktype],
 555                               info,
 556                               pcm,
 557                               sofar,
 558                               quantized,
 559                               nonzero,
 560                               i);
 561         }
 562       }
 563     }
 564     seq+=vi->channels;
 565   }
 566
 567   look->lastframe=vb->sequence;
 568   return(0);
 569 }
 570
 571 static int mapping0_inverse(vorbis_block *vb,vorbis_look_mapping *l){
 572   vorbis_dsp_state     *vd=vb->vd;
 573   vorbis_info          *vi=vd->vi;
 574   codec_setup_info     *ci=vi->codec_setup;
 575   backend_lookup_state *b=vd->backend_state;
 576   vorbis_look_mapping0 *look=(vorbis_look_mapping0 *)l;
 577   vorbis_info_mapping0 *info=look->map;
 578   vorbis_info_mode     *mode=look->mode;
 579   int                   i,j;
 580   long                  n=vb->pcmend=ci->blocksizes[vb->W];
 581
 582   float **pcmbundle=alloca(sizeof(*pcmbundle)*vi->channels);
 583   int    *zerobundle=alloca(sizeof(*zerobundle)*vi->channels);
 584
 585   int   *nonzero  =alloca(sizeof(*nonzero)*vi->channels);
 586   void **floormemo=alloca(sizeof(*floormemo)*vi->channels);
 587
 588   /* time domain information decode (note that applying the
 589      information would have to happen later; we'll probably add a
 590      function entry to the harness for that later */
 591   /* NOT IMPLEMENTED */
 592
 593   /* recover the spectral envelope; store it in the PCM vector for now */
 594   for(i=0;i<vi->channels;i++){
 595     int submap=info->chmuxlist[i];
 596     floormemo[i]=look->floor_func[submap]->
 597       inverse1(vb,look->floor_look[submap]);
 598     if(floormemo[i])
 599       nonzero[i]=1;
 600     else
 601       nonzero[i]=0;
 602     memset(vb->pcm[i],0,sizeof(*vb->pcm[i])*n/2);
 603   }
 604
 605   /* channel coupling can 'dirty' the nonzero listing */
 606   for(i=0;i<info->coupling_steps;i++){
 607     if(nonzero[info->coupling_mag[i]] ||
 608        nonzero[info->coupling_ang[i]]){
 609       nonzero[info->coupling_mag[i]]=1;
 610       nonzero[info->coupling_ang[i]]=1;
 611     }
 612   }
 613
 614   /* recover the residue into our working vectors */
 615   for(i=0;i<info->submaps;i++){
 616     int ch_in_bundle=0;
 617     for(j=0;j<vi->channels;j++){
 618       if(info->chmuxlist[j]==i){
 619         if(nonzero[j])
 620           zerobundle[ch_in_bundle]=1;
 621         else
 622           zerobundle[ch_in_bundle]=0;
 623         pcmbundle[ch_in_bundle++]=vb->pcm[j];
 624       }
 625     }
 626
 627     look->residue_func[i]->inverse(vb,look->residue_look[i],
 628                                    pcmbundle,zerobundle,ch_in_bundle);
 629   }
 630
 631   /* channel coupling */
 632   for(i=info->coupling_steps-1;i>=0;i--){
 633     float *pcmM=vb->pcm[info->coupling_mag[i]];
 634     float *pcmA=vb->pcm[info->coupling_ang[i]];
 635
 636     for(j=0;j<n/2;j++){
 637       float mag=pcmM[j];
 638       float ang=pcmA[j];
 639
 640       if(mag>0)
 641         if(ang>0){
 642           pcmM[j]=mag;
 643           pcmA[j]=mag-ang;
 644         }else{
 645           pcmA[j]=mag;
 646           pcmM[j]=mag+ang;
 647         }
 648       else
 649         if(ang>0){
 650           pcmM[j]=mag;
 651           pcmA[j]=mag+ang;
 652         }else{
 653           pcmA[j]=mag;
 654           pcmM[j]=mag-ang;
 655         }
 656     }
 657   }
 658
 659   /* compute and apply spectral envelope */
 660   for(i=0;i<vi->channels;i++){
 661     float *pcm=vb->pcm[i];
 662     int submap=info->chmuxlist[i];
 663     look->floor_func[submap]->
 664       inverse2(vb,look->floor_look[submap],floormemo[i],pcm);
 665   }
 666
 667   /* transform the PCM data; takes PCM vector, vb; modifies PCM vector */
 668   /* only MDCT right now.... */
 669   for(i=0;i<vi->channels;i++){
 670     float *pcm=vb->pcm[i];
 671     mdct_backward(b->transform[vb->W][0],pcm,pcm);
 672   }
 673
 674   /* window the data */
 675   for(i=0;i<vi->channels;i++){
 676     float *pcm=vb->pcm[i];
 677     if(nonzero[i])
 678       _vorbis_apply_window(pcm,b->window,ci->blocksizes,vb->lW,vb->W,vb->nW);
 679     else
 680       for(j=0;j<n;j++)
 681         pcm[j]=0.f;
 682
 683   }
 684
 685   /* all done! */
 686   return(0);
 687 }
 688
 689 /* export hooks */
 690 vorbis_func_mapping mapping0_exportbundle={
 691   &mapping0_pack,
 692   &mapping0_unpack,
 693   &mapping0_look,
 694   &mapping0_copy_info,
 695   &mapping0_free_info,
 696   &mapping0_free_look,
 697   &mapping0_forward,
 698   &mapping0_inverse
 699 };