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 1.47 2002/03/24 21:04:00 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
 288 static int mapping0_forward(vorbis_block *vb,vorbis_look_mapping *l){
 289   vorbis_dsp_state      *vd=vb->vd;
 290   vorbis_info           *vi=vd->vi;
 291   codec_setup_info      *ci=vi->codec_setup;
 292   backend_lookup_state  *b=vb->vd->backend_state;
 293   bitrate_manager_state *bm=&b->bms;
 294   vorbis_look_mapping0  *look=(vorbis_look_mapping0 *)l;
 295   vorbis_info_mapping0  *info=look->map;
 296   vorbis_info_mode      *mode=look->mode;
 297   vorbis_block_internal *vbi=(vorbis_block_internal *)vb->internal;
 298   int                    n=vb->pcmend;
 299   int i,j;
 300   int   *nonzero=alloca(sizeof(*nonzero)*vi->channels);
 301
 302   float *work=_vorbis_block_alloc(vb,n*sizeof(*work));
 303
 304   float global_ampmax=vbi->ampmax;
 305   float *local_ampmax=alloca(sizeof(*local_ampmax)*vi->channels);
 306   int blocktype=vbi->blocktype;
 307
 308   /* we differentiate between short and long block types to help the
 309      masking engine; the window shapes also matter.
 310      impulse block (a short block in which an impulse occurs)
 311      padding block (a short block that pads between a transitional
 312           long block and an impulse block, or vice versa)
 313      transition block (the wqeird one; a long block with the transition
 314           window; affects bass/midrange response and that must be
 315           accounted for in masking)
 316      long block (run of the mill long block)
 317   */
 318
 319   for(i=0;i<vi->channels;i++){
 320     float scale=4.f/n;
 321     float scale_dB;
 322
 323     /* the following makes things clearer to *me* anyway */
 324     float *pcm     =vb->pcm[i];
 325     float *fft     =work;
 326     float *logfft  =pcm+n/2;
 327
 328     /*float *res     =pcm;
 329     float *mdct    =pcm;
 330     float *codedflr=pcm+n/2;
 331     float *logmax  =work;
 332     float *logmask =work+n/2;*/
 333
 334     scale_dB=todB(&scale);
 335     /*_analysis_output_always("pcm",seq+i,pcm,n,0,0,total-n/2);*/
 336
 337     /* window the PCM data */
 338     _vorbis_apply_window(pcm,b->window,ci->blocksizes,vb->lW,vb->W,vb->nW);
 339     memcpy(fft,pcm,sizeof(*fft)*n);
 340
 341     /*_analysis_output_always("windowed",seq+i,pcm,n,0,0,total-n/2);*/
 342
 343     /* transform the PCM data */
 344     /* only MDCT right now.... */
 345     mdct_forward(b->transform[vb->W][0],pcm,pcm);
 346
 347     /* FFT yields more accurate tonal estimation (not phase sensitive) */
 348     drft_forward(&look->fft_look,fft);
 349     fft[0]*=scale;
 350     logfft[0]=todB(fft);
 351     local_ampmax[i]=logfft[0];
 352     for(j=1;j<n-1;j+=2){
 353       float temp=fft[j]*fft[j]+fft[j+1]*fft[j+1];
 354       temp=logfft[(j+1)>>1]=scale_dB+.5f*todB(&temp);
 355       if(temp>local_ampmax[i])local_ampmax[i]=temp;
 356     }
 357
 358     if(local_ampmax[i]>0.f)local_ampmax[i]=0.f;
 359     if(local_ampmax[i]>global_ampmax)global_ampmax=local_ampmax[i];
 360
 361     /*_analysis_output("fft",seq+i,logfft,n/2,1,0);*/
 362   }
 363
 364   for(i=0;i<vi->channels;i++){
 365     int submap=info->chmuxlist[i];
 366
 367     /* the following makes things clearer to *me* anyway */
 368     float *mdct    =vb->pcm[i];
 369     float *res     =mdct;
 370     float *codedflr=mdct+n/2;
 371     float *logfft  =mdct+n/2;
 372
 373     float *logmdct =work;
 374     float *logmax  =mdct+n/2;
 375     float *logmask =work+n/2;
 376
 377     /*
 378     for(j=0;j<n/2;j+=2){
 379       logmdct[j>>1]=FABS(mdct+j)+FABS(mdct+j+1);
 380       logmdct[j>>1]=todB(logmdct+(j>>1));
 381     }
 382     _analysis_output_always("mdct2",seq+i,logmdct,n/4,1,0,total-n/2);*/
 383
 384
 385     for(j=0;j<n/2;j++)
 386       logmdct[j]=todB(mdct+j);
 387     /*_analysis_output_always("mdct",seq+i,logmdct,n/2,1,0,total-n/2);*/
 388
 389
 390     /* perform psychoacoustics; do masking */
 391     _vp_compute_mask(look->psy_look[blocktype],
 392                      logfft, /* -> logmax */
 393                      logmdct,
 394                      logmask,
 395                      global_ampmax,
 396                      local_ampmax[i],
 397                      bm->avgnoise);
 398
 399     /*_analysis_output("mask",seq+i,logmask,n/2,1,0);*/
 400     /* perform floor encoding */
 401     nonzero[i]=look->floor_func[submap]->
 402       forward(vb,look->floor_look[submap],
 403               mdct,
 404               logmdct,
 405               logmask,
 406               logmax,
 407
 408               codedflr);
 409
 410
 411     _vp_remove_floor(look->psy_look[blocktype],
 412                      mdct,
 413                      codedflr,
 414                      res);
 415
 416     /*for(j=0;j<n/2;j++)
 417       if(fabs(res[j])>1200){
 418         analysis_noisy=1;
 419         fprintf(stderr,"%ld ",seq+i);
 420         }*/
 421
 422     /*_analysis_output("codedflr",seq+i,codedflr,n/2,1,1);*/
 423
 424   }
 425
 426   vbi->ampmax=global_ampmax;
 427
 428   /* partition based prequantization and channel coupling */
 429   /* Steps in prequant and coupling:
 430
 431      classify by |mag| across all pcm vectors
 432
 433      down-couple/down-quantize from perfect residue ->  quantized vector
 434
 435      do{
 436         encode quantized vector; add encoded values to 'so-far' vector
 437         more? [not yet at bitrate/not yet at target]
 438           yes{
 439               down-couple/down-quantize from perfect-'so-far' ->
 440                 quantized vector; when subtracting coupling,
 441                 account for +/- out-of-phase component
 442           }no{
 443               break
 444           }
 445      }
 446      done.
 447
 448      quantization in each iteration is done (after circular normalization
 449      in coupling) using a by-iteration quantization granule value.
 450   */
 451
 452   {
 453     float  **pcm=vb->pcm;
 454     float  **quantized=alloca(sizeof(*quantized)*vi->channels);
 455     float  **sofar=alloca(sizeof(*sofar)*vi->channels);
 456
 457     long  ***classifications=alloca(sizeof(*classifications)*info->submaps);
 458     float ***qbundle=alloca(sizeof(*qbundle)*info->submaps);
 459     float ***pcmbundle=alloca(sizeof(*pcmbundle)*info->submaps);
 460     float ***sobundle=alloca(sizeof(*sobundle)*info->submaps);
 461     int    **zerobundle=alloca(sizeof(*zerobundle)*info->submaps);
 462     int     *chbundle=alloca(sizeof(*chbundle)*info->submaps);
 463     int      chcounter=0;
 464
 465     /* play a little loose with this abstraction */
 466     int   quant_passes=ci->coupling_passes;
 467
 468     for(i=0;i<vi->channels;i++){
 469       quantized[i]=_vorbis_block_alloc(vb,n*sizeof(*sofar[i]));
 470       sofar[i]=quantized[i]+n/2;
 471       memset(sofar[i],0,sizeof(*sofar[i])*n/2);
 472     }
 473
 474     qbundle[0]=alloca(sizeof(*qbundle[0])*vi->channels);
 475     pcmbundle[0]=alloca(sizeof(*pcmbundle[0])*vi->channels);
 476     sobundle[0]=alloca(sizeof(*sobundle[0])*vi->channels);
 477     zerobundle[0]=alloca(sizeof(*zerobundle[0])*vi->channels);
 478
 479     /* initial down-quantized coupling */
 480
 481     if(info->coupling_steps==0){
 482       /* this assumes all or nothing coupling right now.  it should pass
 483          through any channels left uncoupled, but it doesn't do that now */
 484       for(i=0;i<vi->channels;i++){
 485         float *lpcm=pcm[i];
 486         float *lqua=quantized[i];
 487         for(j=0;j<n/2;j++)
 488           lqua[j]=lpcm[j];
 489       }
 490     }else{
 491       _vp_quantize_couple(look->psy_look[blocktype],
 492                           info,
 493                           pcm,
 494                           sofar,
 495                           quantized,
 496                           nonzero,
 497                           0);
 498     }
 499
 500     /* classify, by submap */
 501
 502     for(i=0;i<info->submaps;i++){
 503       int ch_in_bundle=0;
 504       qbundle[i]=qbundle[0]+chcounter;
 505       sobundle[i]=sobundle[0]+chcounter;
 506       zerobundle[i]=zerobundle[0]+chcounter;
 507
 508       for(j=0;j<vi->channels;j++){
 509         if(info->chmuxlist[j]==i){
 510           if(nonzero[j])
 511             zerobundle[i][ch_in_bundle]=1;
 512           else
 513             zerobundle[i][ch_in_bundle]=0;
 514           qbundle[i][ch_in_bundle]=quantized[j];
 515           pcmbundle[i][ch_in_bundle]=pcm[j];
 516           sobundle[i][ch_in_bundle++]=sofar[j];
 517         }
 518       }
 519       chbundle[i]=ch_in_bundle;
 520       chcounter+=ch_in_bundle;
 521
 522       classifications[i]=look->residue_func[i]->
 523         class(vb,look->residue_look[i],pcmbundle[i],zerobundle[i],chbundle[i]);
 524     }
 525
 526     /* actual encoding loop; we pack all the iterations to collect
 527        management data */
 528
 529     for(i=0;i<quant_passes;){
 530
 531       /* perform residue encoding of this pass's quantized residue
 532          vector, according residue mapping */
 533
 534       for(j=0;j<info->submaps;j++){
 535         look->residue_func[j]->
 536           forward(vb,look->residue_look[j],
 537                   qbundle[j],sobundle[j],zerobundle[j],chbundle[j],
 538                   i,classifications[j],vbi->packet_markers);
 539
 540       }
 541       i++;
 542
 543       if(i<quant_passes){
 544         /* down-couple/down-quantize from perfect-'so-far' ->
 545          new quantized vector */
 546         if(info->coupling_steps==0){
 547           /* this assumes all or nothing coupling right now.  it should pass
 548              through any channels left uncoupled, but it doesn't do that now */
 549           int k;
 550           for(k=0;k<vi->channels;k++){
 551             float *lpcm=pcm[k];
 552             float *lsof=sofar[k];
 553             float *lqua=quantized[k];
 554             for(j=0;j<n/2;j++)
 555               lqua[j]=lpcm[j]-lsof[j];
 556           }
 557         }else{
 558
 559           _vp_quantize_couple(look->psy_look[blocktype],
 560                               info,
 561                               pcm,
 562                               sofar,
 563                               quantized,
 564                               nonzero,
 565                               i);
 566         }
 567       }
 568     }
 569     seq+=vi->channels;
 570   }
 571
 572   /*total+=ci->blocksizes[vb->W]/4+ci->blocksizes[vb->nW]/4;*/
 573   look->lastframe=vb->sequence;
 574   return(0);
 575 }
 576
 577 static int mapping0_inverse(vorbis_block *vb,vorbis_look_mapping *l){
 578   vorbis_dsp_state     *vd=vb->vd;
 579   vorbis_info          *vi=vd->vi;
 580   codec_setup_info     *ci=vi->codec_setup;
 581   backend_lookup_state *b=vd->backend_state;
 582   vorbis_look_mapping0 *look=(vorbis_look_mapping0 *)l;
 583   vorbis_info_mapping0 *info=look->map;
 584   vorbis_info_mode     *mode=look->mode;
 585   int                   i,j;
 586   long                  n=vb->pcmend=ci->blocksizes[vb->W];
 587
 588   float **pcmbundle=alloca(sizeof(*pcmbundle)*vi->channels);
 589   int    *zerobundle=alloca(sizeof(*zerobundle)*vi->channels);
 590
 591   int   *nonzero  =alloca(sizeof(*nonzero)*vi->channels);
 592   void **floormemo=alloca(sizeof(*floormemo)*vi->channels);
 593
 594   /* time domain information decode (note that applying the
 595      information would have to happen later; we'll probably add a
 596      function entry to the harness for that later */
 597   /* NOT IMPLEMENTED */
 598
 599   /* recover the spectral envelope; store it in the PCM vector for now */
 600   for(i=0;i<vi->channels;i++){
 601     int submap=info->chmuxlist[i];
 602     floormemo[i]=look->floor_func[submap]->
 603       inverse1(vb,look->floor_look[submap]);
 604     if(floormemo[i])
 605       nonzero[i]=1;
 606     else
 607       nonzero[i]=0;
 608     memset(vb->pcm[i],0,sizeof(*vb->pcm[i])*n/2);
 609   }
 610
 611   /* channel coupling can 'dirty' the nonzero listing */
 612   for(i=0;i<info->coupling_steps;i++){
 613     if(nonzero[info->coupling_mag[i]] ||
 614        nonzero[info->coupling_ang[i]]){
 615       nonzero[info->coupling_mag[i]]=1;
 616       nonzero[info->coupling_ang[i]]=1;
 617     }
 618   }
 619
 620   /* recover the residue into our working vectors */
 621   for(i=0;i<info->submaps;i++){
 622     int ch_in_bundle=0;
 623     for(j=0;j<vi->channels;j++){
 624       if(info->chmuxlist[j]==i){
 625         if(nonzero[j])
 626           zerobundle[ch_in_bundle]=1;
 627         else
 628           zerobundle[ch_in_bundle]=0;
 629         pcmbundle[ch_in_bundle++]=vb->pcm[j];
 630       }
 631     }
 632
 633     look->residue_func[i]->inverse(vb,look->residue_look[i],
 634                                    pcmbundle,zerobundle,ch_in_bundle);
 635   }
 636
 637   /* channel coupling */
 638   for(i=info->coupling_steps-1;i>=0;i--){
 639     float *pcmM=vb->pcm[info->coupling_mag[i]];
 640     float *pcmA=vb->pcm[info->coupling_ang[i]];
 641
 642     for(j=0;j<n/2;j++){
 643       float mag=pcmM[j];
 644       float ang=pcmA[j];
 645
 646       if(mag>0)
 647         if(ang>0){
 648           pcmM[j]=mag;
 649           pcmA[j]=mag-ang;
 650         }else{
 651           pcmA[j]=mag;
 652           pcmM[j]=mag+ang;
 653         }
 654       else
 655         if(ang>0){
 656           pcmM[j]=mag;
 657           pcmA[j]=mag+ang;
 658         }else{
 659           pcmA[j]=mag;
 660           pcmM[j]=mag-ang;
 661         }
 662     }
 663   }
 664
 665   /* compute and apply spectral envelope */
 666   for(i=0;i<vi->channels;i++){
 667     float *pcm=vb->pcm[i];
 668     int submap=info->chmuxlist[i];
 669     look->floor_func[submap]->
 670       inverse2(vb,look->floor_look[submap],floormemo[i],pcm);
 671   }
 672
 673   /* transform the PCM data; takes PCM vector, vb; modifies PCM vector */
 674   /* only MDCT right now.... */
 675   for(i=0;i<vi->channels;i++){
 676     float *pcm=vb->pcm[i];
 677     mdct_backward(b->transform[vb->W][0],pcm,pcm);
 678   }
 679
 680   /* window the data */
 681   for(i=0;i<vi->channels;i++){
 682     float *pcm=vb->pcm[i];
 683     if(nonzero[i])
 684       _vorbis_apply_window(pcm,b->window,ci->blocksizes,vb->lW,vb->W,vb->nW);
 685     else
 686       for(j=0;j<n;j++)
 687         pcm[j]=0.f;
 688
 689   }
 690
 691   /* all done! */
 692   return(0);
 693 }
 694
 695 /* export hooks */
 696 vorbis_func_mapping mapping0_exportbundle={
 697   &mapping0_pack,
 698   &mapping0_unpack,
 699   &mapping0_look,
 700   &mapping0_copy_info,
 701   &mapping0_free_info,
 702   &mapping0_free_look,
 703   &mapping0_forward,
 704   &mapping0_inverse
 705 };
 706