code:
/********************************************************************
 *                                                                  *
 * 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 Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: #ifdef jail to whip a few platforms into the UNIX ideal.
 last mod: $Id: os_types.h 17712 2010-12-03 17:10:02Z xiphmont $

 ********************************************************************/
#ifndef _OS_TYPES_H
#define _OS_TYPES_H

/* make it easy on the folks that want to compile the libs with a
   different malloc than stdlib */
#define _ogg_malloc  malloc
#define _ogg_calloc  calloc
#define _ogg_realloc realloc
#define _ogg_free    free

#if defined(_WIN32) && !defined(SHP)

#  if defined(__CYGWIN__)
#    include <stdint.h>
     typedef int16_t ogg_int16_t;
     typedef uint16_t ogg_uint16_t;
     typedef int32_t ogg_int32_t;
     typedef uint32_t ogg_uint32_t;
     typedef int64_t ogg_int64_t;
     typedef uint64_t ogg_uint64_t;
#  elif defined(__MINGW32__)
#    include <sys/types.h>
     typedef short ogg_int16_t;
     typedef unsigned short ogg_uint16_t;
     typedef int ogg_int32_t;
     typedef unsigned int ogg_uint32_t;
     typedef long long ogg_int64_t;
     typedef unsigned long long ogg_uint64_t;
#  elif defined(__MWERKS__)
     typedef long long ogg_int64_t;
     typedef int ogg_int32_t;
     typedef unsigned int ogg_uint32_t;
     typedef short ogg_int16_t;
     typedef unsigned short ogg_uint16_t;
#  else
     /* MSVC/Borland */
     typedef __int64 ogg_int64_t;
     typedef __int32 ogg_int32_t;
     typedef unsigned __int32 ogg_uint32_t;
     typedef __int16 ogg_int16_t;
     typedef unsigned __int16 ogg_uint16_t;
#  endif

#elif defined(__MACOS__)

#  include <sys/types.h>
   typedef SInt16 ogg_int16_t;
   typedef UInt16 ogg_uint16_t;
   typedef SInt32 ogg_int32_t;
   typedef UInt32 ogg_uint32_t;
   typedef SInt64 ogg_int64_t;

#elif (defined(__APPLE__) && defined(__MACH__)) /* MacOS X Framework build */

#  include <inttypes.h>
   typedef int16_t ogg_int16_t;
   typedef uint16_t ogg_uint16_t;
   typedef int32_t ogg_int32_t;
   typedef uint32_t ogg_uint32_t;
   typedef int64_t ogg_int64_t;

#elif defined(__HAIKU__)

  /* Haiku */
#  include <sys/types.h>
   typedef short ogg_int16_t;
   typedef unsigned short ogg_uint16_t;
   typedef int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long ogg_int64_t;

#elif defined(__BEOS__)

   /* Be */
#  include <inttypes.h>
   typedef int16_t ogg_int16_t;
   typedef uint16_t ogg_uint16_t;
   typedef int32_t ogg_int32_t;
   typedef uint32_t ogg_uint32_t;
   typedef int64_t ogg_int64_t;

#elif defined (__EMX__)

   /* OS/2 GCC */
   typedef short ogg_int16_t;
   typedef unsigned short ogg_uint16_t;
   typedef int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long ogg_int64_t;

#elif defined (DJGPP)

   /* DJGPP */
   typedef short ogg_int16_t;
   typedef int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long ogg_int64_t;

#elif defined(R5900)

   /* PS2 EE */
   typedef long ogg_int64_t;
   typedef int ogg_int32_t;
   typedef unsigned ogg_uint32_t;
   typedef short ogg_int16_t;

#elif defined(__SYMBIAN32__)

   /* Symbian GCC */
   typedef signed short ogg_int16_t;
   typedef unsigned short ogg_uint16_t;
   typedef signed int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long int ogg_int64_t;

#elif defined(__TMS320C6X__)

   /* TI C64x compiler */
   typedef signed short ogg_int16_t;
   typedef unsigned short ogg_uint16_t;
   typedef signed int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long int ogg_int64_t;

#elif defined(SHP)
   typedef short ogg_int16_t;
   typedef unsigned short ogg_uint16_t;
   typedef int ogg_int32_t;
   typedef unsigned int ogg_uint32_t;
   typedef long long ogg_int64_t;
   typedef unsigned long long ogg_uint64_t;
#else

#  include <ogg/config_types.h>

#endif

#endif  /* _OS_TYPES_H */


code:
/********************************************************************
 *                                                                  *
 * 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 1994-2007             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: single-block PCM analysis mode dispatch
 last mod: $Id: analysis.c 16226 2009-07-08 06:43:49Z xiphmont $

 ********************************************************************/

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"
#include "registry.h"
#include "scales.h"
#include "os.h"
#include "misc.h"

/* decides between modes, dispatches to the appropriate mapping. */
int vorbis_analysis(vorbis_block *vb, ogg_packet *op){
  int ret,i;
  vorbis_block_internal *vbi=vb->internal;

  vb->glue_bits=0;
  vb->time_bits=0;
  vb->floor_bits=0;
  vb->res_bits=0;

  /* first things first.  Make sure encode is ready */
  for(i=0;i<PACKETBLOBS;i++)
    oggpack_reset(vbi->packetblob[i]);

  /* we only have one mapping type (0), and we let the mapping code
     itself figure out what soft mode to use.  This allows easier
     bitrate management */

  if((ret=_mapping_P[0]->forward(vb)))
    return(ret);

  if(op){
    if(vorbis_bitrate_managed(vb))
      /* The app is using a bitmanaged mode... but not using the
         bitrate management interface. */
      return(OV_EINVAL);

    op->packet=oggpack_get_buffer(&vb->opb);
    op->bytes=oggpack_bytes(&vb->opb);
    op->b_o_s=0;
    op->e_o_s=vb->eofflag;
    op->granulepos=vb->granulepos;
    op->packetno=vb->sequence; /* for sake of completeness */
  }
  return(0);
}

#ifdef ANALYSIS
int analysis_noisy=1;

/* there was no great place to put this.... */
void _analysis_output_always(char *base,int i,float *v,int n,int bark,int dB,ogg_int64_t off){
  int j;
  FILE *of;
  char buffer[80];

  sprintf(buffer,"%s_%d.m",base,i);
  of=fopen(buffer,"w");

  if(!of)perror("failed to open data dump file");

  for(j=0;j<n;j++){
    if(bark){
      float b=toBARK((4000.f*j/n)+.25);
      fprintf(of,"%f ",b);
    }else
      if(off!=0)
        fprintf(of,"%f ",(double)(j+off)/8000.);
      else
        fprintf(of,"%f ",(double)j);

    if(dB){
      float val;
      if(v[j]==0.)
        val=-140.;
      else
        val=todB(v+j);
      fprintf(of,"%f\n",val);
    }else{
      fprintf(of,"%f\n",v[j]);
    }
  }
  fclose(of);
}

void _analysis_output(char *base,int i,float *v,int n,int bark,int dB,
                      ogg_int64_t off){
  if(analysis_noisy)_analysis_output_always(base,i,v,n,bark,dB,off);
}

#endif

license: mit


code:
/********************************************************************
 *                                                                  *
 * 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 1994-2009             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: libvorbis backend and mapping structures; needed for
           static mode headers
 last mod: $Id: backends.h 16962 2010-03-11 07:30:34Z xiphmont $

 ********************************************************************/

/* this is exposed up here because we need it for static modes.
   Lookups for each backend aren't exposed because there's no reason
   to do so */

#ifndef _vorbis_backend_h_
#define _vorbis_backend_h_

#include "codec_internal.h"

/* this would all be simpler/shorter with templates, but.... */
/* Floor backend generic *****************************************/
typedef struct{
  void                   (*pack)  (vorbis_info_floor *,oggpack_buffer *);
  vorbis_info_floor     *(*unpack)(vorbis_info *,oggpack_buffer *);
  vorbis_look_floor     *(*look)  (vorbis_dsp_state *,vorbis_info_floor *);
  void (*free_info) (vorbis_info_floor *);
  void (*free_look) (vorbis_look_floor *);
  void *(*inverse1)  (struct vorbis_block *,vorbis_look_floor *);
  int   (*inverse2)  (struct vorbis_block *,vorbis_look_floor *,
                     void *buffer,float *);
} vorbis_func_floor;

typedef struct{
  int   order;
  long  rate;
  long  barkmap;

  int   ampbits;
  int   ampdB;

  int   numbooks; /* <= 16 */
  int   books[16];

  float lessthan;     /* encode-only config setting hacks for libvorbis */
  float greaterthan;  /* encode-only config setting hacks for libvorbis */

} vorbis_info_floor0;

#define VIF_POSIT 63
#define VIF_CLASS 16
#define VIF_PARTS 31
typedef struct{
  int   partitions;                /* 0 to 31 */
  int   partitionclass[VIF_PARTS]; /* 0 to 15 */

  int   class_dim[VIF_CLASS];        /* 1 to 8 */
  int   class_subs[VIF_CLASS];       /* 0,1,2,3 (bits: 1<<n poss) */
  int   class_book[VIF_CLASS];       /* subs ^ dim entries */
  int   class_subbook[VIF_CLASS][8]; /* [VIF_CLASS][subs] */

  int   mult;                      /* 1 2 3 or 4 */
  int   postlist[VIF_POSIT+2];    /* first two implicit */

  /* encode side analysis parameters */
  float maxover;
  float maxunder;
  float maxerr;

  float twofitweight;
  float twofitatten;

  int   n;

} vorbis_info_floor1;

/* Residue backend generic *****************************************/
typedef struct{
  void                 (*pack)  (vorbis_info_residue *,oggpack_buffer *);
  vorbis_info_residue *(*unpack)(vorbis_info *,oggpack_buffer *);
  vorbis_look_residue *(*look)  (vorbis_dsp_state *,
                                 vorbis_info_residue *);
  void (*free_info)    (vorbis_info_residue *);
  void (*free_look)    (vorbis_look_residue *);
  long **(*class)      (struct vorbis_block *,vorbis_look_residue *,
                        int **,int *,int);
  int  (*forward)      (oggpack_buffer *,struct vorbis_block *,
                        vorbis_look_residue *,
                        int **,int *,int,long **,int);
  int  (*inverse)      (struct vorbis_block *,vorbis_look_residue *,
                        float **,int *,int);
} vorbis_func_residue;

typedef struct vorbis_info_residue0{
/* block-partitioned VQ coded straight residue */
  long  begin;
  long  end;

  /* first stage (lossless partitioning) */
  int    grouping;         /* group n vectors per partition */
  int    partitions;       /* possible codebooks for a partition */
  int    partvals;         /* partitions ^ groupbook dim */
  int    groupbook;        /* huffbook for partitioning */
  int    secondstages[64]; /* expanded out to pointers in lookup */
  int    booklist[512];    /* list of second stage books */

  const int classmetric1[64];
  const int classmetric2[64];
} vorbis_info_residue0;

/* Mapping backend generic *****************************************/
typedef struct{
  void                 (*pack)  (vorbis_info *,vorbis_info_mapping *,
                                 oggpack_buffer *);
  vorbis_info_mapping *(*unpack)(vorbis_info *,oggpack_buffer *);
  void (*free_info)    (vorbis_info_mapping *);
  int  (*forward)      (struct vorbis_block *vb);
  int  (*inverse)      (struct vorbis_block *vb,vorbis_info_mapping *);
} vorbis_func_mapping;

typedef struct vorbis_info_mapping0{
  int   submaps;  /* <= 16 */
  int   chmuxlist[256];   /* up to 256 channels in a Vorbis stream */

  int   floorsubmap[16];   /* [mux] submap to floors */
  int   residuesubmap[16]; /* [mux] submap to residue */

  int   coupling_steps;
  int   coupling_mag[256];
  int   coupling_ang[256];

} vorbis_info_mapping0;

#endif


code:
/********************************************************************
 *                                                                  *
 * 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 1994-2009             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: bitrate tracking and management
 last mod: $Id: bitrate.c 16227 2009-07-08 06:58:46Z xiphmont $

 ********************************************************************/

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"
#include "os.h"
#include "misc.h"
#include "bitrate.h"

/* compute bitrate tracking setup  */
void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bm){
  codec_setup_info *ci=vi->codec_setup;
  bitrate_manager_info *bi=&ci->bi;

  memset(bm,0,sizeof(*bm));

  if(bi && (bi->reservoir_bits>0)){
    long ratesamples=vi->rate;
    int  halfsamples=ci->blocksizes[0]>>1;

    bm->short_per_long=ci->blocksizes[1]/ci->blocksizes[0];
    bm->managed=1;

    bm->avg_bitsper= rint(1.*bi->avg_rate*halfsamples/ratesamples);
    bm->min_bitsper= rint(1.*bi->min_rate*halfsamples/ratesamples);
    bm->max_bitsper= rint(1.*bi->max_rate*halfsamples/ratesamples);

    bm->avgfloat=PACKETBLOBS/2;

    /* not a necessary fix, but one that leads to a more balanced
       typical initialization */
    {
      long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
      bm->minmax_reservoir=desired_fill;
      bm->avg_reservoir=desired_fill;
    }

  }
}

void vorbis_bitrate_clear(bitrate_manager_state *bm){
  memset(bm,0,sizeof(*bm));
  return;
}

int vorbis_bitrate_managed(vorbis_block *vb){
  vorbis_dsp_state      *vd=vb->vd;
  private_state         *b=vd->backend_state;
  bitrate_manager_state *bm=&b->bms;

  if(bm && bm->managed)return(1);
  return(0);
}

/* finish taking in the block we just processed */
int vorbis_bitrate_addblock(vorbis_block *vb){
  vorbis_block_internal *vbi=vb->internal;
  vorbis_dsp_state      *vd=vb->vd;
  private_state         *b=vd->backend_state;
  bitrate_manager_state *bm=&b->bms;
  vorbis_info           *vi=vd->vi;
  codec_setup_info      *ci=vi->codec_setup;
  bitrate_manager_info  *bi=&ci->bi;

  int  choice=rint(bm->avgfloat);
  long this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
  long min_target_bits=(vb->W?bm->min_bitsper*bm->short_per_long:bm->min_bitsper);
  long max_target_bits=(vb->W?bm->max_bitsper*bm->short_per_long:bm->max_bitsper);
  int  samples=ci->blocksizes[vb->W]>>1;
  long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
  if(!bm->managed){
    /* not a bitrate managed stream, but for API simplicity, we'll
       buffer the packet to keep the code path clean */

    if(bm->vb)return(-1); /* one has been submitted without
                             being claimed */
    bm->vb=vb;
    return(0);
  }

  bm->vb=vb;

  /* look ahead for avg floater */
  if(bm->avg_bitsper>0){
    double slew=0.;
    long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
    double slewlimit= 15./bi->slew_damp;

    /* choosing a new floater:
       if we're over target, we slew down
       if we're under target, we slew up

       choose slew as follows: look through packetblobs of this frame
       and set slew as the first in the appropriate direction that
       gives us the slew we want.  This may mean no slew if delta is
       already favorable.

       Then limit slew to slew max */

    if(bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
      while(choice>0 && this_bits>avg_target_bits &&
            bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
        choice--;
        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
      }
    }else if(bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
      while(choice+1<PACKETBLOBS && this_bits<avg_target_bits &&
            bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
        choice++;
        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
      }
    }

    slew=rint(choice-bm->avgfloat)/samples*vi->rate;
    if(slew<-slewlimit)slew=-slewlimit;
    if(slew>slewlimit)slew=slewlimit;
    choice=rint(bm->avgfloat+= slew/vi->rate*samples);
    this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
  }

  /* enforce min(if used) on the current floater (if used) */
  if(bm->min_bitsper>0){
    /* do we need to force the bitrate up? */
    if(this_bits<min_target_bits){
      while(bm->minmax_reservoir-(min_target_bits-this_bits)<0){
        choice++;
        if(choice>=PACKETBLOBS)break;
        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
      }
    }
  }

  /* enforce max (if used) on the current floater (if used) */
  if(bm->max_bitsper>0){
    /* do we need to force the bitrate down? */
    if(this_bits>max_target_bits){
      while(bm->minmax_reservoir+(this_bits-max_target_bits)>bi->reservoir_bits){
        choice--;
        if(choice<0)break;
        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
      }
    }
  }

  /* Choice of packetblobs now made based on floater, and min/max
     requirements. Now boundary check extreme choices */

  if(choice<0){
    /* choosing a smaller packetblob is insufficient to trim bitrate.
       frame will need to be truncated */
    long maxsize=(max_target_bits+(bi->reservoir_bits-bm->minmax_reservoir))/8;
    bm->choice=choice=0;

    if(oggpack_bytes(vbi->packetblob[choice])>maxsize){

      oggpack_writetrunc(vbi->packetblob[choice],maxsize*8);
      this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
    }
  }else{
    long minsize=(min_target_bits-bm->minmax_reservoir+7)/8;
    if(choice>=PACKETBLOBS)
      choice=PACKETBLOBS-1;

    bm->choice=choice;

    /* prop up bitrate according to demand. pad this frame out with zeroes */
    minsize-=oggpack_bytes(vbi->packetblob[choice]);
    while(minsize-->0)oggpack_write(vbi->packetblob[choice],0,8);
    this_bits=oggpack_bytes(vbi->packetblob[choice])*8;

  }

  /* now we have the final packet and the final packet size.  Update statistics */
  /* min and max reservoir */
  if(bm->min_bitsper>0 || bm->max_bitsper>0){

    if(max_target_bits>0 && this_bits>max_target_bits){
      bm->minmax_reservoir+=(this_bits-max_target_bits);
    }else if(min_target_bits>0 && this_bits<min_target_bits){
      bm->minmax_reservoir+=(this_bits-min_target_bits);
    }else{
      /* inbetween; we want to take reservoir toward but not past desired_fill */
      if(bm->minmax_reservoir>desired_fill){
        if(max_target_bits>0){ /* logical bulletproofing against initialization state */
          bm->minmax_reservoir+=(this_bits-max_target_bits);
          if(bm->minmax_reservoir<desired_fill)bm->minmax_reservoir=desired_fill;
        }else{
          bm->minmax_reservoir=desired_fill;
        }
      }else{
        if(min_target_bits>0){ /* logical bulletproofing against initialization state */
          bm->minmax_reservoir+=(this_bits-min_target_bits);
          if(bm->minmax_reservoir>desired_fill)bm->minmax_reservoir=desired_fill;
        }else{
          bm->minmax_reservoir=desired_fill;
        }
      }
    }
  }

  /* avg reservoir */
  if(bm->avg_bitsper>0){
    long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
    bm->avg_reservoir+=this_bits-avg_target_bits;
  }

  return(0);
}

int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,ogg_packet *op){
  private_state         *b=vd->backend_state;
  bitrate_manager_state *bm=&b->bms;
  vorbis_block          *vb=bm->vb;
  int                    choice=PACKETBLOBS/2;
  if(!vb)return 0;

  if(op){
    vorbis_block_internal *vbi=vb->internal;

    if(vorbis_bitrate_managed(vb))
      choice=bm->choice;

    op->packet=oggpack_get_buffer(vbi->packetblob[choice]);
    op->bytes=oggpack_bytes(vbi->packetblob[choice]);
    op->b_o_s=0;
    op->e_o_s=vb->eofflag;
    op->granulepos=vb->granulepos;
    op->packetno=vb->sequence; /* for sake of completeness */
  }

  bm->vb=0;
  return(1);
}


code:
/********************************************************************
 *                                                                  *
 * 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 1994-2007             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: bitrate tracking and management
 last mod: $Id: bitrate.h 13293 2007-07-24 00:09:47Z xiphmont $

 ********************************************************************/

#ifndef _V_BITRATE_H_
#define _V_BITRATE_H_

#include "vorbis/codec.h"
#include "codec_internal.h"
#include "os.h"

/* encode side bitrate tracking */
typedef struct bitrate_manager_state {
  int            managed;

  long           avg_reservoir;
  long           minmax_reservoir;
  long           avg_bitsper;
  long           min_bitsper;
  long           max_bitsper;

  long           short_per_long;
  double         avgfloat;

  vorbis_block  *vb;
  int            choice;
} bitrate_manager_state;

typedef struct bitrate_manager_info{
  long           avg_rate;
  long           min_rate;
  long           max_rate;
  long           reservoir_bits;
  double         reservoir_bias;

  double         slew_damp;

} bitrate_manager_info;

extern void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bs);
extern void vorbis_bitrate_clear(bitrate_manager_state *bs);
extern int vorbis_bitrate_managed(vorbis_block *vb);
extern int vorbis_bitrate_addblock(vorbis_block *vb);
extern int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd, ogg_packet *op);

#endif


code:
/********************************************************************
 *                                                                  *
 * 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 1994-2009             *
 * by the Xiph.Org Foundation http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: PCM data vector blocking, windowing and dis/reassembly
 last mod: $Id: block.c 17561 2010-10-23 10:34:24Z xiphmont $

 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){
  int i;
  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));
    vbi->ampmax=-9999;

    for(i=0;i<PACKETBLOBS;i++){
      if(i==PACKETBLOBS/2){
        vbi->packetblob[i]=&vb->opb;
      }else{
        vbi->packetblob[i]=
          _ogg_calloc(1,sizeof(oggpack_buffer));
      }
      oggpack_writeinit(vbi->packetblob[i]);
    }
  }

  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){
  int i;
  vorbis_block_internal *vbi=vb->internal;

  _vorbis_block_ripcord(vb);
  if(vb->localstore)_ogg_free(vb->localstore);

  if(vbi){
    for(i=0;i<PACKETBLOBS;i++){
      oggpack_writeclear(vbi->packetblob[i]);
      if(i!=PACKETBLOBS/2)_ogg_free(vbi->packetblob[i]);
    }
    _ogg_free(vbi);
  }
  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;
  private_state *b=NULL;
  int hs;

  if(ci==NULL) return 1;
  hs=ci->halfrate_flag;

  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]>>hs);
  mdct_init(b->transform[1][0],ci->blocksizes[1]>>hs);

  /* Vorbis I uses only window type 0 */
  b->window[0]=ilog2(ci->blocksizes[0])-6;
  b->window[1]=ilog2(ci->blocksizes[1])-6;

  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++){
        if(ci->book_param[i]==NULL)
          goto abort_books;
        if(vorbis_book_init_decode(ci->fullbooks+i,ci->book_param[i]))
          goto abort_books;
        /* 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;
 abort_books:
  for(i=0;i<ci->books;i++){
    if(ci->book_param[i]!=NULL){
      vorbis_staticbook_destroy(ci->book_param[i]);
      ci->book_param[i]=NULL;
    }
  }
  vorbis_dsp_clear(v);
  return -1;
}

/* arbitrary settings and spec-mandated numbers get filled in here */
int vorbis_analysis_init(vorbis_dsp_state *v,vorbis_info *vi){
  private_state *b=NULL;

  if(_vds_shared_init(v,vi,1))return 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);

  /* compressed audio packets start after the headers
     with sequence number 3 */
  v->sequence=3;

  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);
    private_state *b=v->backend_state;

    if(b){

      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){
        if(ci)
          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){
        if(ci)
          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){
        if(ci)
          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){
      if(vi)
        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;
  private_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=16;
  float *lpc=alloca(order*sizeof(*lpc));
  float *work=alloca(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);

#if 0
      if(v->vi->channels==2){
        if(i==0)
          _analysis_output("predataL",0,work,v->pcm_current-v->centerW,0,0,0);
        else
          _analysis_output("predataR",0,work,v->pcm_current-v->centerW,0,0,0);
      }else{
        _analysis_output("predata",0,work,v->pcm_current-v->centerW,0,0,0);
      }
#endif

      /* 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];

    }
  }
}

/* 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;

  if(vals<=0){
    int order=32;
    int i;
    float *lpc=alloca(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]));

      }
    }
  }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;
  private_state *b=v->backend_state;
  vorbis_look_psy_global *g=b->psy_g_look;
  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_restart(vorbis_dsp_state *v){
  vorbis_info *vi=v->vi;
  codec_setup_info *ci;
  int hs;

  if(!v->backend_state)return -1;
  if(!vi)return -1;
  ci=vi->codec_setup;
  if(!ci)return -1;
  hs=ci->halfrate_flag;

  v->centerW=ci->blocksizes[1]>>(hs+1);
  v->pcm_current=v->centerW>>hs;

  v->pcm_returned=-1;
  v->granulepos=-1;
  v->sequence=-1;
  v->eofflag=0;
  ((private_state *)(v->backend_state))->sample_count=-1;

  return(0);
}

int vorbis_synthesis_init(vorbis_dsp_state *v,vorbis_info *vi){
  if(_vds_shared_init(v,vi,0)){
    vorbis_dsp_clear(v);
    return 1;
  }
  vorbis_synthesis_restart(v);
  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;
  private_state *b=v->backend_state;
  int hs=ci->halfrate_flag;
  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)||
     (v->sequence+1 != vb->sequence)){
    v->granulepos=-1; /* out of sequence; lose count */
    b->sample_count=-1;
  }

  v->sequence=vb->sequence;

  if(vb->pcm){  /* no pcm to process if vorbis_synthesis_trackonly
                   was called on block */
    int n=ci->blocksizes[v->W]>>(hs+1);
    int n0=ci->blocksizes[0]>>(hs+1);
    int n1=ci->blocksizes[1]>>(hs+1);

    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 */

    for(j=0;j<vi->channels;j++){
      /* the overlap/add section */
      if(v->lW){
        if(v->W){
          /* large/large */
          float *w=_vorbis_window_get(b->window[1]-hs);
          float *pcm=v->pcm[j]+prevCenter;
          float *p=vb->pcm[j];
          for(i=0;i<n1;i++)
            pcm[i]=pcm[i]*w[n1-i-1] + p[i]*w[i];
        }else{
          /* large/small */
          float *w=_vorbis_window_get(b->window[0]-hs);
          float *pcm=v->pcm[j]+prevCenter+n1/2-n0/2;
          float *p=vb->pcm[j];
          for(i=0;i<n0;i++)
            pcm[i]=pcm[i]*w[n0-i-1] +p[i]*w[i];
        }
      }else{
        if(v->W){
          /* small/large */
          float *w=_vorbis_window_get(b->window[0]-hs);
          float *pcm=v->pcm[j]+prevCenter;
          float *p=vb->pcm[j]+n1/2-n0/2;
          for(i=0;i<n0;i++)
            pcm[i]=pcm[i]*w[n0-i-1] +p[i]*w[i];
          for(;i<n1/2+n0/2;i++)
            pcm[i]=p[i];
        }else{
          /* small/small */
          float *w=_vorbis_window_get(b->window[0]-hs);
          float *pcm=v->pcm[j]+prevCenter;
          float *p=vb->pcm[j];
          for(i=0;i<n0;i++)
            pcm[i]=pcm[i]*w[n0-i-1] +p[i]*w[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)>>hs);
    }

  }

  /* 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(b->sample_count==-1){
    b->sample_count=0;
  }else{
    b->sample_count+=ci->blocksizes[v->lW]/4+ci->blocksizes[v->W]/4;
  }

  if(v->granulepos==-1){
    if(vb->granulepos!=-1){ /* only set if we have a position to set to */

      v->granulepos=vb->granulepos;

      /* is this a short page? */
      if(b->sample_count>v->granulepos){
        /* corner case; if this is both the first and last audio page,
           then spec says the end is cut, not beginning */
       long extra=b->sample_count-vb->granulepos;

        /* we use ogg_int64_t for granule positions because a
           uint64 isn't universally available.  Unfortunately,
           that means granposes can be 'negative' and result in
           extra being negative */
        if(extra<0)
          extra=0;

        if(vb->eofflag){
          /* trim the end */
          /* no preceding granulepos; assume we started at zero (we'd
             have to in a short single-page stream) */
          /* granulepos could be -1 due to a seek, but that would result
             in a long count, not short count */

          /* Guard against corrupt/malicious frames that set EOP and
             a backdated granpos; don't rewind more samples than we
             actually have */
          if(extra > (v->pcm_current - v->pcm_returned)<<hs)
            extra = (v->pcm_current - v->pcm_returned)<<hs;

          v->pcm_current-=extra>>hs;
        }else{
          /* trim the beginning */
          v->pcm_returned+=extra>>hs;
          if(v->pcm_returned>v->pcm_current)
            v->pcm_returned=v->pcm_current;
        }

      }

    }
  }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(extra)
          if(vb->eofflag){
            /* partial last frame.  Strip the extra samples off */

            /* Guard against corrupt/malicious frames that set EOP and
               a backdated granpos; don't rewind more samples than we
               actually have */
            if(extra > (v->pcm_current - v->pcm_returned)<<hs)
              extra = (v->pcm_current - v->pcm_returned)<<hs;

            /* we use ogg_int64_t for granule positions because a
               uint64 isn't universally available.  Unfortunately,
               that means granposes can be 'negative' and result in
               extra being negative */
            if(extra<0)
              extra=0;

            v->pcm_current-=extra>>hs;
          } /* 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);
}

/* intended for use with a specific vorbisfile feature; we want access
   to the [usually synthetic/postextrapolated] buffer and lapping at
   the end of a decode cycle, specifically, a half-short-block worth.
   This funtion works like pcmout above, except it will also expose
   this implicit buffer data not normally decoded. */
int vorbis_synthesis_lapout(vorbis_dsp_state *v,float ***pcm){
  vorbis_info *vi=v->vi;
  codec_setup_info *ci=vi->codec_setup;
  int hs=ci->halfrate_flag;

  int n=ci->blocksizes[v->W]>>(hs+1);
  int n0=ci->blocksizes[0]>>(hs+1);
  int n1=ci->blocksizes[1]>>(hs+1);
  int i,j;

  if(v->pcm_returned<0)return 0;

  /* our returned data ends at pcm_returned; because the synthesis pcm
     buffer is a two-fragment ring, that means our data block may be
     fragmented by buffering, wrapping or a short block not filling
     out a buffer.  To simplify things, we unfragment if it's at all
     possibly needed. Otherwise, we'd need to call lapout more than
     once as well as hold additional dsp state.  Opt for
     simplicity. */

  /* centerW was advanced by blockin; it would be the center of the
     *next* block */
  if(v->centerW==n1){
    /* the data buffer wraps; swap the halves */
    /* slow, sure, small */
    for(j=0;j<vi->channels;j++){
      float *p=v->pcm[j];
      for(i=0;i<n1;i++){
        float temp=p[i];
        p[i]=p[i+n1];
        p[i+n1]=temp;
      }
    }

    v->pcm_current-=n1;
    v->pcm_returned-=n1;
    v->centerW=0;
  }

  /* solidify buffer into contiguous space */
  if((v->lW^v->W)==1){
    /* long/short or short/long */
    for(j=0;j<vi->channels;j++){
      float *s=v->pcm[j];
      float *d=v->pcm[j]+(n1-n0)/2;
      for(i=(n1+n0)/2-1;i>=0;--i)
        d[i]=s[i];
    }
    v->pcm_returned+=(n1-n0)/2;
    v->pcm_current+=(n1-n0)/2;
  }else{
    if(v->lW==0){
      /* short/short */
      for(j=0;j<vi->channels;j++){
        float *s=v->pcm[j];
        float *d=v->pcm[j]+n1-n0;
        for(i=n0-1;i>=0;--i)
          d[i]=s[i];
      }
      v->pcm_returned+=n1-n0;
      v->pcm_current+=n1-n0;
    }
  }

  if(pcm){
    int i;
    for(i=0;i<vi->channels;i++)
      v->pcmret[i]=v->pcm[i]+v->pcm_returned;
    *pcm=v->pcmret;
  }

  return(n1+n-v->pcm_returned);

}

float *vorbis_window(vorbis_dsp_state *v,int W){
  vorbis_info *vi=v->vi;
  codec_setup_info *ci=vi->codec_setup;
  int hs=ci->halfrate_flag;
  private_state *b=v->backend_state;

  if(b->window[W]-1<0)return NULL;
  return _vorbis_window_get(b->window[W]-hs);
}