move mp3 stuff to /sys/src/cmd/audio, add ogg vorbis, add play

1 files changed, 838 insertions, 0 deletions

diff --git a/sys/src/cmd/audio/libvorbis/block.c b/sys/src/cmd/audio/libvorbis/block.c
new file mode 100644
index 000000000..86784b7b8
--- /dev/null
+++ b/sys/src/cmd/audio/libvorbis/block.c
@@ -0,0 +1,838 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
+ * by the XIPHOPHORUS Company http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************
+
+ function: PCM data vector blocking, windowing and dis/reassembly
+ last mod: $Id: block.c,v 1.67 2002/07/11 06:40:48 xiphmont Exp $
+
+ Handle windowing, overlap-add, etc of the PCM vectors.  This is made
+ more amusing by Vorbis' current two allowed block sizes.
+ 
+ ********************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ogg/ogg.h>
+#include "vorbis/codec.h"
+#include "codec_internal.h"
+
+#include "window.h"
+#include "mdct.h"
+#include "lpc.h"
+#include "registry.h"
+#include "misc.h"
+
+static int ilog2(unsigned int v){
+  int ret=0;
+  if(v)--v;
+  while(v){
+    ret++;
+    v>>=1;
+  }
+  return(ret);
+}
+
+/* pcm accumulator examples (not exhaustive):
+
+ <-------------- lW ---------------->
+                   <--------------- W ---------------->
+:            .....|.....       _______________         |
+:        .'''     |     '''_---      |       |\        |
+:.....'''         |_____--- '''......|       | \_______|
+:.................|__________________|_______|__|______|
+                  |<------ Sl ------>|      > Sr <     |endW
+                  |beginSl           |endSl  |  |endSr   
+                  |beginW            |endlW  |beginSr
+
+
+                      |< lW >|       
+                   <--------------- W ---------------->
+                  |   |  ..  ______________            |
+                  |   | '  `/        |     ---_        |
+                  |___.'___/`.       |         ---_____| 
+                  |_______|__|_______|_________________|
+                  |      >|Sl|<      |<------ Sr ----->|endW
+                  |       |  |endSl  |beginSr          |endSr
+                  |beginW |  |endlW                     
+                  mult[0] |beginSl                     mult[n]
+
+ <-------------- lW ----------------->
+                          |<--W-->|                               
+:            ..............  ___  |   |                    
+:        .'''             |`/   \ |   |                       
+:.....'''                 |/`....\|...|                    
+:.........................|___|___|___|                  
+                          |Sl |Sr |endW    
+                          |   |   |endSr
+                          |   |beginSr
+                          |   |endSl
+			  |beginSl
+			  |beginW
+*/
+
+/* block abstraction setup *********************************************/
+
+#ifndef WORD_ALIGN
+#define WORD_ALIGN 8
+#endif
+
+int vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb){
+  memset(vb,0,sizeof(*vb));
+  vb->vd=v;
+  vb->localalloc=0;
+  vb->localstore=NULL;
+  if(v->analysisp){
+    vorbis_block_internal *vbi=
+      vb->internal=_ogg_calloc(1,sizeof(vorbis_block_internal));
+    oggpack_writeinit(&vb->opb);
+    vbi->ampmax=-9999;
+  }
+  
+  return(0);
+}
+
+void *_vorbis_block_alloc(vorbis_block *vb,long bytes){
+  bytes=(bytes+(WORD_ALIGN-1)) & ~(WORD_ALIGN-1);
+  if(bytes+vb->localtop>vb->localalloc){
+    /* can't just _ogg_realloc... there are outstanding pointers */
+    if(vb->localstore){
+      struct alloc_chain *link=_ogg_malloc(sizeof(*link));
+      vb->totaluse+=vb->localtop;
+      link->next=vb->reap;
+      link->ptr=vb->localstore;
+      vb->reap=link;
+    }
+    /* highly conservative */
+    vb->localalloc=bytes;
+    vb->localstore=_ogg_malloc(vb->localalloc);
+    vb->localtop=0;
+  }
+  {
+    void *ret=(void *)(((char *)vb->localstore)+vb->localtop);
+    vb->localtop+=bytes;
+    return ret;
+  }
+}
+
+/* reap the chain, pull the ripcord */
+void _vorbis_block_ripcord(vorbis_block *vb){
+  /* reap the chain */
+  struct alloc_chain *reap=vb->reap;
+  while(reap){
+    struct alloc_chain *next=reap->next;
+    _ogg_free(reap->ptr);
+    memset(reap,0,sizeof(*reap));
+    _ogg_free(reap);
+    reap=next;
+  }
+  /* consolidate storage */
+  if(vb->totaluse){
+    vb->localstore=_ogg_realloc(vb->localstore,vb->totaluse+vb->localalloc);
+    vb->localalloc+=vb->totaluse;
+    vb->totaluse=0;
+  }
+
+  /* pull the ripcord */
+  vb->localtop=0;
+  vb->reap=NULL;
+}
+
+int vorbis_block_clear(vorbis_block *vb){
+  if(vb->vd)
+    if(vb->vd->analysisp)
+      oggpack_writeclear(&vb->opb);
+  _vorbis_block_ripcord(vb);
+  if(vb->localstore)_ogg_free(vb->localstore);
+
+  if(vb->internal)
+    _ogg_free(vb->internal);
+
+  memset(vb,0,sizeof(*vb));
+  return(0);
+}
+
+/* Analysis side code, but directly related to blocking.  Thus it's
+   here and not in analysis.c (which is for analysis transforms only).
+   The init is here because some of it is shared */
+
+static int _vds_shared_init(vorbis_dsp_state *v,vorbis_info *vi,int encp){
+  int i;
+  codec_setup_info *ci=vi->codec_setup;
+  backend_lookup_state *b=NULL;
+
+  memset(v,0,sizeof(*v));
+  b=v->backend_state=_ogg_calloc(1,sizeof(*b));
+
+  v->vi=vi;
+  b->modebits=ilog2(ci->modes);
+
+  b->transform[0]=_ogg_calloc(VI_TRANSFORMB,sizeof(*b->transform[0]));
+  b->transform[1]=_ogg_calloc(VI_TRANSFORMB,sizeof(*b->transform[1]));
+
+  /* MDCT is tranform 0 */
+
+  b->transform[0][0]=_ogg_calloc(1,sizeof(mdct_lookup));
+  b->transform[1][0]=_ogg_calloc(1,sizeof(mdct_lookup));
+  mdct_init(b->transform[0][0],ci->blocksizes[0]);
+  mdct_init(b->transform[1][0],ci->blocksizes[1]);
+
+  /* Vorbis I uses only window type 0 */
+  b->window[0]=_vorbis_window(0,ci->blocksizes[0]/2);
+  b->window[1]=_vorbis_window(0,ci->blocksizes[1]/2);
+
+  if(encp){ /* encode/decode differ here */
+
+    /* analysis always needs an fft */
+    drft_init(&b->fft_look[0],ci->blocksizes[0]);
+    drft_init(&b->fft_look[1],ci->blocksizes[1]);
+
+    /* finish the codebooks */
+    if(!ci->fullbooks){
+      ci->fullbooks=_ogg_calloc(ci->books,sizeof(*ci->fullbooks));
+      for(i=0;i<ci->books;i++)
+	vorbis_book_init_encode(ci->fullbooks+i,ci->book_param[i]);
+    }
+
+    b->psy=_ogg_calloc(ci->psys,sizeof(*b->psy));
+    for(i=0;i<ci->psys;i++){
+      _vp_psy_init(b->psy+i,
+		   ci->psy_param[i],
+		   &ci->psy_g_param,
+		   ci->blocksizes[ci->psy_param[i]->blockflag]/2,
+		   vi->rate);
+    }
+
+    v->analysisp=1;
+  }else{
+    /* finish the codebooks */
+    if(!ci->fullbooks){
+      ci->fullbooks=_ogg_calloc(ci->books,sizeof(*ci->fullbooks));
+      for(i=0;i<ci->books;i++){
+	vorbis_book_init_decode(ci->fullbooks+i,ci->book_param[i]);
+	/* decode codebooks are now standalone after init */
+	vorbis_staticbook_destroy(ci->book_param[i]);
+	ci->book_param[i]=NULL;
+      }
+    }
+  }
+
+  /* initialize the storage vectors. blocksize[1] is small for encode,
+     but the correct size for decode */
+  v->pcm_storage=ci->blocksizes[1];
+  v->pcm=_ogg_malloc(vi->channels*sizeof(*v->pcm));
+  v->pcmret=_ogg_malloc(vi->channels*sizeof(*v->pcmret));
+  {
+    int i;
+    for(i=0;i<vi->channels;i++)
+      v->pcm[i]=_ogg_calloc(v->pcm_storage,sizeof(*v->pcm[i]));
+  }
+
+  /* all 1 (large block) or 0 (small block) */
+  /* explicitly set for the sake of clarity */
+  v->lW=0; /* previous window size */
+  v->W=0;  /* current window size */
+
+  /* all vector indexes */
+  v->centerW=ci->blocksizes[1]/2;
+
+  v->pcm_current=v->centerW;
+
+  /* initialize all the backend lookups */
+  b->flr=_ogg_calloc(ci->floors,sizeof(*b->flr));
+  b->residue=_ogg_calloc(ci->residues,sizeof(*b->residue));
+
+  for(i=0;i<ci->floors;i++)
+    b->flr[i]=_floor_P[ci->floor_type[i]]->
+      look(v,ci->floor_param[i]);
+
+  for(i=0;i<ci->residues;i++)
+    b->residue[i]=_residue_P[ci->residue_type[i]]->
+      look(v,ci->residue_param[i]);    
+
+  return(0);
+}
+
+/* arbitrary settings and spec-mandated numbers get filled in here */
+int vorbis_analysis_init(vorbis_dsp_state *v,vorbis_info *vi){
+  backend_lookup_state *b=NULL;
+
+  _vds_shared_init(v,vi,1);
+  b=v->backend_state;
+  b->psy_g_look=_vp_global_look(vi);
+
+  /* Initialize the envelope state storage */
+  b->ve=_ogg_calloc(1,sizeof(*b->ve));
+  _ve_envelope_init(b->ve,vi);
+
+  vorbis_bitrate_init(vi,&b->bms);
+
+  return(0);
+}
+
+void vorbis_dsp_clear(vorbis_dsp_state *v){
+  int i;
+  if(v){
+    vorbis_info *vi=v->vi;
+    codec_setup_info *ci=(vi?vi->codec_setup:NULL);
+    backend_lookup_state *b=v->backend_state;
+
+    if(b){
+      if(b->window[0])
+	_ogg_free(b->window[0]);
+      if(b->window[1])
+	_ogg_free(b->window[1]);
+	
+      if(b->ve){
+	_ve_envelope_clear(b->ve);
+	_ogg_free(b->ve);
+      }
+
+      if(b->transform[0]){
+	mdct_clear(b->transform[0][0]);
+	_ogg_free(b->transform[0][0]);
+	_ogg_free(b->transform[0]);
+      }
+      if(b->transform[1]){
+	mdct_clear(b->transform[1][0]);
+	_ogg_free(b->transform[1][0]);
+	_ogg_free(b->transform[1]);
+      }
+
+      if(b->flr){
+	for(i=0;i<ci->floors;i++)
+	  _floor_P[ci->floor_type[i]]->
+	    free_look(b->flr[i]);
+	_ogg_free(b->flr);
+      }
+      if(b->residue){
+	for(i=0;i<ci->residues;i++)
+	  _residue_P[ci->residue_type[i]]->
+	    free_look(b->residue[i]);
+	_ogg_free(b->residue);
+      }
+      if(b->psy){
+	for(i=0;i<ci->psys;i++)
+	  _vp_psy_clear(b->psy+i);
+	_ogg_free(b->psy);
+      }
+
+      if(b->psy_g_look)_vp_global_free(b->psy_g_look);
+      vorbis_bitrate_clear(&b->bms);
+
+      drft_clear(&b->fft_look[0]);
+      drft_clear(&b->fft_look[1]);
+
+    }
+    
+    if(v->pcm){
+      for(i=0;i<vi->channels;i++)
+	if(v->pcm[i])_ogg_free(v->pcm[i]);
+      _ogg_free(v->pcm);
+      if(v->pcmret)_ogg_free(v->pcmret);
+    }
+
+    if(b){
+      /* free header, header1, header2 */
+      if(b->header)_ogg_free(b->header);
+      if(b->header1)_ogg_free(b->header1);
+      if(b->header2)_ogg_free(b->header2);
+      _ogg_free(b);
+    }
+    
+    memset(v,0,sizeof(*v));
+  }
+}
+
+float **vorbis_analysis_buffer(vorbis_dsp_state *v, int vals){
+  int i;
+  vorbis_info *vi=v->vi;
+  backend_lookup_state *b=v->backend_state;
+
+  /* free header, header1, header2 */
+  if(b->header)_ogg_free(b->header);b->header=NULL;
+  if(b->header1)_ogg_free(b->header1);b->header1=NULL;
+  if(b->header2)_ogg_free(b->header2);b->header2=NULL;
+
+  /* Do we have enough storage space for the requested buffer? If not,
+     expand the PCM (and envelope) storage */
+    
+  if(v->pcm_current+vals>=v->pcm_storage){
+    v->pcm_storage=v->pcm_current+vals*2;
+   
+    for(i=0;i<vi->channels;i++){
+      v->pcm[i]=_ogg_realloc(v->pcm[i],v->pcm_storage*sizeof(*v->pcm[i]));
+    }
+  }
+
+  for(i=0;i<vi->channels;i++)
+    v->pcmret[i]=v->pcm[i]+v->pcm_current;
+    
+  return(v->pcmret);
+}
+
+static void _preextrapolate_helper(vorbis_dsp_state *v){
+  int i;
+  int order=32;
+  float *lpc=malloc(order*sizeof(*lpc));
+  float *work=malloc(v->pcm_current*sizeof(*work));
+  long j;
+  v->preextrapolate=1;
+
+  if(v->pcm_current-v->centerW>order*2){ /* safety */
+    for(i=0;i<v->vi->channels;i++){
+      /* need to run the extrapolation in reverse! */
+      for(j=0;j<v->pcm_current;j++)
+	work[j]=v->pcm[i][v->pcm_current-j-1];
+      
+      /* prime as above */
+      vorbis_lpc_from_data(work,lpc,v->pcm_current-v->centerW,order);
+      
+      /* run the predictor filter */
+      vorbis_lpc_predict(lpc,work+v->pcm_current-v->centerW-order,
+			 order,
+			 work+v->pcm_current-v->centerW,
+			 v->centerW);
+
+      for(j=0;j<v->pcm_current;j++)
+	v->pcm[i][v->pcm_current-j-1]=work[j];
+
+    }
+  }
+  free(work);
+  free(lpc);
+  return;
+}
+
+
+/* call with val<=0 to set eof */
+
+int vorbis_analysis_wrote(vorbis_dsp_state *v, int vals){
+  vorbis_info *vi=v->vi;
+  codec_setup_info *ci=vi->codec_setup;
+  /*backend_lookup_state *b=v->backend_state;*/
+
+  if(vals<=0){
+    int order=32;
+    int i;
+    float *lpc=malloc(order*sizeof(*lpc));
+
+    /* if it wasn't done earlier (very short sample) */
+    if(!v->preextrapolate)
+      _preextrapolate_helper(v);
+
+    /* We're encoding the end of the stream.  Just make sure we have
+       [at least] a few full blocks of zeroes at the end. */
+    /* actually, we don't want zeroes; that could drop a large
+       amplitude off a cliff, creating spread spectrum noise that will
+       suck to encode.  Extrapolate for the sake of cleanliness. */
+
+    vorbis_analysis_buffer(v,ci->blocksizes[1]*3); 
+    v->eofflag=v->pcm_current;
+    v->pcm_current+=ci->blocksizes[1]*3;
+
+    for(i=0;i<vi->channels;i++){
+      if(v->eofflag>order*2){
+	/* extrapolate with LPC to fill in */
+	long n;
+
+	/* make a predictor filter */
+	n=v->eofflag;
+	if(n>ci->blocksizes[1])n=ci->blocksizes[1];
+	vorbis_lpc_from_data(v->pcm[i]+v->eofflag-n,lpc,n,order);
+
+	/* run the predictor filter */
+	vorbis_lpc_predict(lpc,v->pcm[i]+v->eofflag-order,order,
+			   v->pcm[i]+v->eofflag,v->pcm_current-v->eofflag);
+      }else{
+	/* not enough data to extrapolate (unlikely to happen due to
+           guarding the overlap, but bulletproof in case that
+           assumtion goes away). zeroes will do. */
+	memset(v->pcm[i]+v->eofflag,0,
+	       (v->pcm_current-v->eofflag)*sizeof(*v->pcm[i]));
+
+      }
+    }
+    free(lpc);
+  }else{
+
+    if(v->pcm_current+vals>v->pcm_storage) {
+      return(OV_EINVAL);
+    }
+    v->pcm_current+=vals;
+
+    /* we may want to reverse extrapolate the beginning of a stream
+       too... in case we're beginning on a cliff! */
+    /* clumsy, but simple.  It only runs once, so simple is good. */
+    if(!v->preextrapolate && v->pcm_current-v->centerW>ci->blocksizes[1])
+      _preextrapolate_helper(v);
+
+  }
+  return(0);
+}
+
+/* do the deltas, envelope shaping, pre-echo and determine the size of
+   the next block on which to continue analysis */
+int vorbis_analysis_blockout(vorbis_dsp_state *v,vorbis_block *vb){
+  int i;
+  vorbis_info *vi=v->vi;
+  codec_setup_info *ci=vi->codec_setup;
+  backend_lookup_state *b=v->backend_state;
+  vorbis_look_psy_global *g=b->psy_g_look;
+  vorbis_info_psy_global *gi=&ci->psy_g_param;
+  long beginW=v->centerW-ci->blocksizes[v->W]/2,centerNext;
+  vorbis_block_internal *vbi=(vorbis_block_internal *)vb->internal;
+
+  /* check to see if we're started... */
+  if(!v->preextrapolate)return(0);
+
+  /* check to see if we're done... */
+  if(v->eofflag==-1)return(0);
+
+  /* By our invariant, we have lW, W and centerW set.  Search for
+     the next boundary so we can determine nW (the next window size)
+     which lets us compute the shape of the current block's window */
+
+  /* we do an envelope search even on a single blocksize; we may still
+     be throwing more bits at impulses, and envelope search handles
+     marking impulses too. */
+  {  
+    long bp=_ve_envelope_search(v);
+
+    if(bp==-1){
+
+      if(v->eofflag==0) return(0); /* not enough data currently to search for a
+				     full long block */
+      v->nW=0;
+    }else{
+
+      if(ci->blocksizes[0]==ci->blocksizes[1])
+	v->nW=0;
+      else
+	v->nW=bp;
+    }
+  }
+
+  centerNext=v->centerW+ci->blocksizes[v->W]/4+ci->blocksizes[v->nW]/4;
+
+  {
+    /* center of next block + next block maximum right side. */
+
+    long blockbound=centerNext+ci->blocksizes[v->nW]/2;
+    if(v->pcm_current<blockbound)return(0); /* not enough data yet;
+                                               although this check is
+                                               less strict that the
+                                               _ve_envelope_search,
+                                               the search is not run
+                                               if we only use one
+                                               block size */
+
+
+  }
+  
+  /* fill in the block.  Note that for a short window, lW and nW are *short*
+     regardless of actual settings in the stream */
+
+  _vorbis_block_ripcord(vb);
+  vb->lW=v->lW;
+  vb->W=v->W;
+  vb->nW=v->nW;
+
+  if(v->W){
+    if(!v->lW || !v->nW){
+      vbi->blocktype=BLOCKTYPE_TRANSITION;
+      fprintf(stderr,"-");
+    }else{
+      vbi->blocktype=BLOCKTYPE_LONG;
+      fprintf(stderr,"_");
+    }
+  }else{
+    if(_ve_envelope_mark(v)){
+      vbi->blocktype=BLOCKTYPE_IMPULSE;
+      fprintf(stderr,"|");
+
+    }else{
+      vbi->blocktype=BLOCKTYPE_PADDING;
+      fprintf(stderr,".");
+
+    }
+  }
+ 
+  vb->vd=v;
+  vb->sequence=v->sequence++;
+  vb->granulepos=v->granulepos;
+  vb->pcmend=ci->blocksizes[v->W];
+  
+  /* copy the vectors; this uses the local storage in vb */
+
+  /* this tracks 'strongest peak' for later psychoacoustics */
+  /* moved to the global psy state; clean this mess up */
+  if(vbi->ampmax>g->ampmax)g->ampmax=vbi->ampmax;
+  g->ampmax=_vp_ampmax_decay(g->ampmax,v);
+  vbi->ampmax=g->ampmax;
+  
+  vb->pcm=_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);
+  vbi->pcmdelay=_vorbis_block_alloc(vb,sizeof(*vbi->pcmdelay)*vi->channels);
+  for(i=0;i<vi->channels;i++){
+    vbi->pcmdelay[i]=
+      _vorbis_block_alloc(vb,(vb->pcmend+beginW)*sizeof(*vbi->pcmdelay[i]));
+    memcpy(vbi->pcmdelay[i],v->pcm[i],(vb->pcmend+beginW)*sizeof(*vbi->pcmdelay[i]));
+    vb->pcm[i]=vbi->pcmdelay[i]+beginW;
+    
+    /* before we added the delay 
+       vb->pcm[i]=_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));
+       memcpy(vb->pcm[i],v->pcm[i]+beginW,ci->blocksizes[v->W]*sizeof(*vb->pcm[i]));
+    */
+    
+  }
+  
+  /* handle eof detection: eof==0 means that we've not yet received EOF
+                           eof>0  marks the last 'real' sample in pcm[]
+                           eof<0  'no more to do'; doesn't get here */
+
+  if(v->eofflag){
+    if(v->centerW>=v->eofflag){
+      v->eofflag=-1;
+      vb->eofflag=1;
+      return(1);
+    }
+  }
+
+  /* advance storage vectors and clean up */
+  {
+    int new_centerNext=ci->blocksizes[1]/2;
+    int movementW=centerNext-new_centerNext;
+
+    if(movementW>0){
+
+      _ve_envelope_shift(b->ve,movementW);
+      v->pcm_current-=movementW;
+      
+      for(i=0;i<vi->channels;i++)
+	memmove(v->pcm[i],v->pcm[i]+movementW,
+		v->pcm_current*sizeof(*v->pcm[i]));
+      
+      
+      v->lW=v->W;
+      v->W=v->nW;
+      v->centerW=new_centerNext;
+      
+      if(v->eofflag){
+	v->eofflag-=movementW;
+	if(v->eofflag<=0)v->eofflag=-1;
+	/* do not add padding to end of stream! */
+	if(v->centerW>=v->eofflag){
+	  v->granulepos+=movementW-(v->centerW-v->eofflag);
+	}else{
+	  v->granulepos+=movementW;
+	}
+      }else{
+	v->granulepos+=movementW;
+      }
+    }
+  }
+
+  /* done */
+  return(1);
+}
+
+int vorbis_synthesis_init(vorbis_dsp_state *v,vorbis_info *vi){
+  _vds_shared_init(v,vi,0);
+
+  v->pcm_returned=-1;
+  v->granulepos=-1;
+  v->sequence=-1;
+
+  return(0);
+}
+
+/* Unlike in analysis, the window is only partially applied for each
+   block.  The time domain envelope is not yet handled at the point of
+   calling (as it relies on the previous block). */
+
+int vorbis_synthesis_blockin(vorbis_dsp_state *v,vorbis_block *vb){
+  vorbis_info *vi=v->vi;
+  codec_setup_info *ci=vi->codec_setup;
+  int i,j;
+
+  if(!vb)return(OV_EINVAL);
+  if(v->pcm_current>v->pcm_returned  && v->pcm_returned!=-1)return(OV_EINVAL);
+    
+  v->lW=v->W;
+  v->W=vb->W;
+  v->nW=-1;
+  
+  if(v->sequence+1 != vb->sequence)v->granulepos=-1; /* out of sequence;
+							lose count */
+  v->sequence=vb->sequence;
+  
+  if(vb->pcm){  /* not pcm to process if vorbis_synthesis_trackonly 
+		   was called on block */
+    int n=ci->blocksizes[v->W]/2;
+    int n0=ci->blocksizes[0]/2;
+    int n1=ci->blocksizes[1]/2;
+    
+    int thisCenter;
+    int prevCenter;
+    
+    v->glue_bits+=vb->glue_bits;
+    v->time_bits+=vb->time_bits;
+    v->floor_bits+=vb->floor_bits;
+    v->res_bits+=vb->res_bits;
+    
+    if(v->centerW){
+      thisCenter=n1;
+      prevCenter=0;
+    }else{
+	thisCenter=0;
+	prevCenter=n1;
+    }
+    
+    /* v->pcm is now used like a two-stage double buffer.  We don't want
+       to have to constantly shift *or* adjust memory usage.  Don't
+       accept a new block until the old is shifted out */
+    
+    /* overlap/add PCM */
+    
+    for(j=0;j<vi->channels;j++){
+      /* the overlap/add section */
+      if(v->lW){
+	if(v->W){
+	  /* large/large */
+	  float *pcm=v->pcm[j]+prevCenter;
+	  float *p=vb->pcm[j];
+	  for(i=0;i<n1;i++)
+	    pcm[i]+=p[i];
+	}else{
+	  /* large/small */
+	  float *pcm=v->pcm[j]+prevCenter+n1/2-n0/2;
+	  float *p=vb->pcm[j];
+	  for(i=0;i<n0;i++)
+	    pcm[i]+=p[i];
+	}
+      }else{
+	if(v->W){
+	  /* small/large */
+	  float *pcm=v->pcm[j]+prevCenter;
+	  float *p=vb->pcm[j]+n1/2-n0/2;
+	  for(i=0;i<n0;i++)
+	    pcm[i]+=p[i];
+	  for(;i<n1/2+n0/2;i++)
+	    pcm[i]=p[i];
+	}else{
+	  /* small/small */
+	  float *pcm=v->pcm[j]+prevCenter;
+	  float *p=vb->pcm[j];
+	  for(i=0;i<n0;i++)
+	    pcm[i]+=p[i];
+	}
+      }
+      
+      /* the copy section */
+      {
+	float *pcm=v->pcm[j]+thisCenter;
+	float *p=vb->pcm[j]+n;
+	for(i=0;i<n;i++)
+	  pcm[i]=p[i];
+      }
+    }
+    
+    if(v->centerW)
+      v->centerW=0;
+    else
+      v->centerW=n1;
+    
+    /* deal with initial packet state; we do this using the explicit
+       pcm_returned==-1 flag otherwise we're sensitive to first block
+       being short or long */
+    
+    if(v->pcm_returned==-1){
+      v->pcm_returned=thisCenter;
+      v->pcm_current=thisCenter;
+    }else{
+      v->pcm_returned=prevCenter;
+      v->pcm_current=prevCenter+
+	ci->blocksizes[v->lW]/4+
+	ci->blocksizes[v->W]/4;
+    }
+    
+  }
+
+  /* track the frame number... This is for convenience, but also
+     making sure our last packet doesn't end with added padding.  If
+     the last packet is partial, the number of samples we'll have to
+     return will be past the vb->granulepos.
+     
+     This is not foolproof!  It will be confused if we begin
+     decoding at the last page after a seek or hole.  In that case,
+     we don't have a starting point to judge where the last frame
+     is.  For this reason, vorbisfile will always try to make sure
+     it reads the last two marked pages in proper sequence */
+  
+  if(v->granulepos==-1){
+    if(vb->granulepos!=-1){ /* only set if we have a position to set to */
+      v->granulepos=vb->granulepos;
+    }
+  }else{
+    v->granulepos+=ci->blocksizes[v->lW]/4+ci->blocksizes[v->W]/4;
+    if(vb->granulepos!=-1 && v->granulepos!=vb->granulepos){
+      
+      if(v->granulepos>vb->granulepos){
+	long extra=v->granulepos-vb->granulepos;
+	
+	if(vb->eofflag){
+	  /* partial last frame.  Strip the extra samples off */
+	  v->pcm_current-=extra;
+	}else if(vb->sequence == 1){
+	  /* ^^^ argh, this can be 1 from seeking! */
+	  
+	  
+	  /* partial first frame.  Discard extra leading samples */
+	  v->pcm_returned+=extra;
+	  if(v->pcm_returned>v->pcm_current)
+	    v->pcm_returned=v->pcm_current;
+	  
+	} /* else {Shouldn't happen *unless* the bitstream is out of
+	     spec.  Either way, believe the bitstream } */
+      } /* else {Shouldn't happen *unless* the bitstream is out of
+	   spec.  Either way, believe the bitstream } */
+      v->granulepos=vb->granulepos;
+    }
+  }
+  
+  /* Update, cleanup */
+  
+  if(vb->eofflag)v->eofflag=1;
+  return(0);
+  
+}
+
+/* pcm==NULL indicates we just want the pending samples, no more */
+int vorbis_synthesis_pcmout(vorbis_dsp_state *v,float ***pcm){
+  vorbis_info *vi=v->vi;
+  if(v->pcm_returned>-1 && v->pcm_returned<v->pcm_current){
+    if(pcm){
+      int i;
+      for(i=0;i<vi->channels;i++)
+	v->pcmret[i]=v->pcm[i]+v->pcm_returned;
+      *pcm=v->pcmret;
+    }
+    return(v->pcm_current-v->pcm_returned);
+  }
+  return(0);
+}
+
+int vorbis_synthesis_read(vorbis_dsp_state *v,int n){
+  if(n && v->pcm_returned+n>v->pcm_current)return(OV_EINVAL);
+  v->pcm_returned+=n;
+  return(0);
+}
+