rockbox/apps/codecs/libtremor/floor0.c

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' 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 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: floor backend 0 implementation

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

#include "config-tremor.h"
#include <string.h>
#include <math.h>
#include "ogg.h"
#include "ivorbiscodec.h"
#include "codec_internal.h"
#include "registry.h"
#include "codebook.h"
#include "misc.h"
#include "os.h"

#define LSP_FRACBITS 14

typedef struct {
  long n;
  int ln;
  int  m;
  int *linearmap;

  vorbis_info_floor0 *vi;
  ogg_int32_t *lsp_look;

} vorbis_look_floor0;

/*************** LSP decode ********************/

#include "lsp_lookup.h"

/* interpolated 1./sqrt(p) where .5 <= a < 1. (.100000... to .111111...) in
   16.16 format 
   returns in m.8 format */

static const long ADJUST_SQRT2[2]  ={8192,5792};
static inline ogg_int32_t vorbis_invsqlook_i(long a,long e){
  long i=(a&0x7fff)>>(INVSQ_LOOKUP_I_SHIFT-1); 
  long d=a&INVSQ_LOOKUP_I_MASK;                              /*  0.10 */
  long val=INVSQ_LOOKUP_I[i]-                                /*  1.16 */
    ((INVSQ_LOOKUP_IDel[i]*d)>>INVSQ_LOOKUP_I_SHIFT);        /* result 1.16 */
  val*=ADJUST_SQRT2[e&1];
  e=(e>>1)+21;
  return(val>>e);
}

/* interpolated lookup based fromdB function, domain -140dB to 0dB only */
/* a is in n.12 format */
static inline ogg_int32_t vorbis_fromdBlook_i(long a){
  int i=(-a)>>(12-FROMdB2_SHIFT);
  if(i<0) return 0x7fffffff;
  if(i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))return 0;
  
  return FROMdB_LOOKUP[i>>FROMdB_SHIFT] * FROMdB2_LOOKUP[i&FROMdB2_MASK];
}

/* interpolated lookup based cos function, domain 0 to PI only */
/* a is in 0.16 format, where 0==0, 2^^16-1==PI, return 0.14 */
static inline ogg_int32_t vorbis_coslook_i(long a){
  int i=a>>COS_LOOKUP_I_SHIFT;
  int d=a&COS_LOOKUP_I_MASK;
  return COS_LOOKUP_I[i]- ((d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>>
                           COS_LOOKUP_I_SHIFT);
}

/* interpolated lookup based cos function */
/* a is in 0.16 format, where 0==0, 2^^16==PI, return .LSP_FRACBITS */
static inline ogg_int32_t vorbis_coslook2_i(long a){
  a=a&0x1ffff;

  if(a>0x10000)a=0x20000-a;
  {               
    int i=a>>COS_LOOKUP_I_SHIFT;
    int d=a&COS_LOOKUP_I_MASK;
    a=((COS_LOOKUP_I[i]<<COS_LOOKUP_I_SHIFT)-
       d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>>
      (COS_LOOKUP_I_SHIFT-LSP_FRACBITS+14);
  }
  
  return(a);
}

static const int barklook[28] ={
  0,100,200,301,          405,516,635,766,
  912,1077,1263,1476,     1720,2003,2333,2721,
  3184,3742,4428,5285,    6376,7791,9662,12181,
  15624,20397,27087,36554
};

/* used in init only; interpolate the long way */
static inline ogg_int32_t toBARK(int n){
  int i;
  for(i=0;i<27;i++) 
    if(n>=barklook[i] && n<barklook[i+1])break;
  
  if(i==27){
    return 27<<15;
  }else{
    int gap=barklook[i+1]-barklook[i];
    int del=n-barklook[i];

    return((i<<15)+((del<<15)/gap));
  }
}

static const unsigned char MLOOP_1[64]  ={
   0,10,11,11, 12,12,12,12, 13,13,13,13, 13,13,13,13,
  14,14,14,14, 14,14,14,14, 14,14,14,14, 14,14,14,14,
  15,15,15,15, 15,15,15,15, 15,15,15,15, 15,15,15,15,
  15,15,15,15, 15,15,15,15, 15,15,15,15, 15,15,15,15,
};

static const unsigned char MLOOP_2[64]  ={
  0,4,5,5, 6,6,6,6, 7,7,7,7, 7,7,7,7,
  8,8,8,8, 8,8,8,8, 8,8,8,8, 8,8,8,8,
  9,9,9,9, 9,9,9,9, 9,9,9,9, 9,9,9,9,
  9,9,9,9, 9,9,9,9, 9,9,9,9, 9,9,9,9,
};

static const unsigned char MLOOP_3[8]  ={0,1,2,2,3,3,3,3};

static void vorbis_lsp_to_curve(ogg_int32_t *curve,int *map,int n,int ln,
                                ogg_int32_t *lsp,int m,
                                ogg_int32_t amp,
                                ogg_int32_t ampoffset,
                                ogg_int32_t *icos){

  (void)ln;
  /* 0 <= m < 256 */

  /* set up for using all int later */
  int i;
  int ampoffseti=ampoffset*4096;
  int ampi=amp;
  ogg_int32_t *ilsp=(ogg_int32_t *)alloca(m*sizeof(*ilsp));
  /* lsp is in 8.24, range 0 to PI; coslook wants it in .16 0 to 1*/
  for(i=0;i<m;i++){
#ifndef _LOW_ACCURACY_
    ogg_int32_t val=MULT32(lsp[i],0x517cc2);
#else
    ogg_int32_t val=((lsp[i]>>10)*0x517d)>>14;
#endif

    /* safeguard against a malicious stream */
    if(val<0 || (val>>COS_LOOKUP_I_SHIFT)>=COS_LOOKUP_I_SZ){
      memset(curve,0,sizeof(*curve)*n);
      return;
    }

    ilsp[i]=vorbis_coslook_i(val);
  }

  i=0;
  while(i<n){
    int j,k=map[i];
    ogg_uint32_t pi=46341; /* 2**-.5 in 0.16 */
    ogg_uint32_t qi=46341;
    ogg_int32_t qexp=0,shift;
    ogg_int32_t wi=icos[k];

#ifdef _V_LSP_MATH_ASM
    (void)shift; /* kill warnings */
    (void)j;
    lsp_loop_asm(&qi,&pi,&qexp,ilsp,wi,m);

    pi=((pi*pi)>>16);
    qi=((qi*qi)>>16);
    
    if(m&1){
      qexp= qexp*2-28*((m+1)>>1)+m;
      pi*=(1<<14)-((wi*wi)>>14);
      qi+=pi>>14;     
    }else{
      qexp= qexp*2-13*m;
      
      pi*=(1<<14)-wi;
      qi*=(1<<14)+wi;
      
      qi=(qi+pi)>>14;
    }
    
    if(qi&0xffff0000){ /* checks for 1.xxxxxxxxxxxxxxxx */
      qi>>=1; qexp++; 
    }else
      lsp_norm_asm(&qi,&qexp);

#else

    qi*=labs(ilsp[0]-wi);
    pi*=labs(ilsp[1]-wi);

    for(j=3;j<m;j+=2){
      if(!(shift=MLOOP_1[(pi|qi)>>25]))
        if(!(shift=MLOOP_2[(pi|qi)>>19]))
          shift=MLOOP_3[(pi|qi)>>16];
      qi=(qi>>shift)*labs(ilsp[j-1]-wi);
      pi=(pi>>shift)*labs(ilsp[j]-wi);
      qexp+=shift;
    }
    if(!(shift=MLOOP_1[(pi|qi)>>25]))
      if(!(shift=MLOOP_2[(pi|qi)>>19]))
        shift=MLOOP_3[(pi|qi)>>16];

    /* pi,qi normalized collectively, both tracked using qexp */

    if(m&1){
      /* odd order filter; slightly assymetric */
      /* the last coefficient */
      qi=(qi>>shift)*labs(ilsp[j-1]-wi);
      pi=(pi>>shift)<<14;
      qexp+=shift;

      if(!(shift=MLOOP_1[(pi|qi)>>25]))
        if(!(shift=MLOOP_2[(pi|qi)>>19]))
          shift=MLOOP_3[(pi|qi)>>16];
      
      pi>>=shift;
      qi>>=shift;
      qexp+=shift-14*((m+1)>>1);

      pi=((pi*pi)>>16);
      qi=((qi*qi)>>16);
      qexp=qexp*2+m;

      pi*=(1<<14)-((wi*wi)>>14);
      qi+=pi>>14;

    }else{
      /* even order filter; still symmetric */

      /* p*=p(1-w), q*=q(1+w), let normalization drift because it isn't
         worth tracking step by step */
      
      pi>>=shift;
      qi>>=shift;
      qexp+=shift-7*m;

      pi=((pi*pi)>>16);
      qi=((qi*qi)>>16);
      qexp=qexp*2+m;
      
      pi*=(1<<14)-wi;
      qi*=(1<<14)+wi;
      qi=(qi+pi)>>14;
      
    }
    

    /* we've let the normalization drift because it wasn't important;
       however, for the lookup, things must be normalized again.  We
       need at most one right shift or a number of left shifts */

    if(qi&0xffff0000){ /* checks for 1.xxxxxxxxxxxxxxxx */
      qi>>=1; qexp++; 
    }else
      while(qi && !(qi&0x8000)){ /* checks for 0.0xxxxxxxxxxxxxxx or less*/
        qi<<=1; qexp--; 
      }

#endif

    amp=vorbis_fromdBlook_i(ampi*                     /*  n.4         */
                            vorbis_invsqlook_i(qi,qexp)- 
                                                      /*  m.8, m+n<=8 */
                            ampoffseti);              /*  8.12[0]     */
    
#ifdef _LOW_ACCURACY_
    amp>>=9;
#endif
    curve[i]= MULT31_SHIFT15(curve[i],amp);
    while(map[++i]==k) curve[i]= MULT31_SHIFT15(curve[i],amp);
  }
}

/*************** vorbis decode glue ************/

static void floor0_free_info(vorbis_info_floor *i){
  vorbis_info_floor0 *info=(vorbis_info_floor0 *)i;
  if(info){
    memset(info,0,sizeof(*info));
    _ogg_free(info);
  }
}

static void floor0_free_look(vorbis_look_floor *i){
  vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
  if(look){

    if(look->linearmap)_ogg_free(look->linearmap);
    if(look->lsp_look)_ogg_free(look->lsp_look);
    memset(look,0,sizeof(*look));
    _ogg_free(look);
  }
}

static vorbis_info_floor *floor0_unpack (vorbis_info *vi,oggpack_buffer *opb){
  codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
  int j;

  vorbis_info_floor0 *info=(vorbis_info_floor0 *)_ogg_malloc(sizeof(*info));
  info->order=oggpack_read(opb,8);
  info->rate=oggpack_read(opb,16);
  info->barkmap=oggpack_read(opb,16);
  info->ampbits=oggpack_read(opb,6);
  info->ampdB=oggpack_read(opb,8);
  info->numbooks=oggpack_read(opb,4)+1;
  
  if(info->order<1)goto err_out;
  if(info->rate<1)goto err_out;
  if(info->barkmap<1)goto err_out;
  if(info->numbooks<1)goto err_out;
    
  for(j=0;j<info->numbooks;j++){
    info->books[j]=oggpack_read(opb,8);
    if(info->books[j]<0 || info->books[j]>=ci->books)goto err_out;
  }
  return(info);

 err_out:
  floor0_free_info(info);
  return(NULL);
}

/* initialize Bark scale and normalization lookups.  We could do this
   with static tables, but Vorbis allows a number of possible
   combinations, so it's best to do it computationally.

   The below is authoritative in terms of defining scale mapping.
   Note that the scale depends on the sampling rate as well as the
   linear block and mapping sizes */

static vorbis_look_floor *floor0_look (vorbis_dsp_state *vd,vorbis_info_mode *mi,
                              vorbis_info_floor *i){
  int j;
  //  ogg_int32_t scale; 
  vorbis_info        *vi=vd->vi;
  codec_setup_info   *ci=(codec_setup_info *)vi->codec_setup;
  vorbis_info_floor0 *info=(vorbis_info_floor0 *)i;
  vorbis_look_floor0 *look=(vorbis_look_floor0 *)_ogg_calloc(1,sizeof(*look));
  look->m=info->order;
  look->n=ci->blocksizes[mi->blockflag]/2;
  look->ln=info->barkmap;
  look->vi=info;

  /* the mapping from a linear scale to a smaller bark scale is
     straightforward.  We do *not* make sure that the linear mapping
     does not skip bark-scale bins; the decoder simply skips them and
     the encoder may do what it wishes in filling them.  They're
     necessary in some mapping combinations to keep the scale spacing
     accurate */
  look->linearmap=(int *)_ogg_malloc((look->n+1)*sizeof(*look->linearmap));
  for(j=0;j<look->n;j++){

    int val=(look->ln*
             ((toBARK(info->rate/2*j/look->n)<<11)/toBARK(info->rate/2)))>>11;

    if(val>=look->ln)val=look->ln-1; /* guard against the approximation */
    look->linearmap[j]=val;
  }
  look->linearmap[j]=-1;

  look->lsp_look=(ogg_int32_t *)_ogg_malloc(look->ln*sizeof(*look->lsp_look));
  for(j=0;j<look->ln;j++)
    look->lsp_look[j]=vorbis_coslook2_i(0x10000*j/look->ln);

  return look;
}

static void *floor0_inverse1(vorbis_block *vb,vorbis_look_floor *i){
  vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
  vorbis_info_floor0 *info=look->vi;
  int j,k;
  
  int ampraw=oggpack_read(&vb->opb,info->ampbits);
  if(ampraw>0){ /* also handles the -1 out of data case */
    long maxval=(1<<info->ampbits)-1;
    int amp=((ampraw*info->ampdB)<<4)/maxval;
    int booknum=oggpack_read(&vb->opb,_ilog(info->numbooks));
    
    if(booknum!=-1 && booknum<info->numbooks){ /* be paranoid */
      codec_setup_info  *ci=(codec_setup_info *)vb->vd->vi->codec_setup;
      codebook *b=ci->fullbooks+info->books[booknum];
      ogg_int32_t last=0;
      ogg_int32_t *lsp=(ogg_int32_t *)_vorbis_block_alloc(vb,sizeof(*lsp)*(look->m+1));
            
      for(j=0;j<look->m;j+=b->dim)
        if(vorbis_book_decodev_set(b,lsp+j,&vb->opb,b->dim,-24)==-1)goto eop;
      for(j=0;j<look->m;){
        for(k=0;k<b->dim;k++,j++)lsp[j]+=last;
        last=lsp[j-1];
      }
      
      lsp[look->m]=amp;
      return(lsp);
    }
  }
 eop:
  return(NULL);
}

static int floor0_inverse2(vorbis_block *vb,vorbis_look_floor *i,
                           void *memo,ogg_int32_t *out){
  vorbis_look_floor0 *look=(vorbis_look_floor0 *)i;
  vorbis_info_floor0 *info=look->vi;
  (void)vb;

  if(memo){
    ogg_int32_t *lsp=(ogg_int32_t *)memo;
    ogg_int32_t amp=lsp[look->m];

    /* take the coefficients back to a spectral envelope curve */
    vorbis_lsp_to_curve(out,look->linearmap,look->n,look->ln,
                        lsp,look->m,amp,info->ampdB,look->lsp_look);
    return(1);
  }
  memset(out,0,sizeof(*out)*look->n);
  return(0);
}

/* export hooks */
const vorbis_func_floor floor0_exportbundle ICONST_ATTR ={
  &floor0_unpack,&floor0_look,&floor0_free_info,
  &floor0_free_look,&floor0_inverse1,&floor0_inverse2
};