context_ini.c

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/*!
 *************************************************************************************
 * \file context_ini.c
 *
 * \brief
 *    CABAC context initializations
 *
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *    - Detlev Marpe                    <marpe@hhi.de>
 *    - Heiko Schwarz                   <hschwarz@hhi.de>
 **************************************************************************************
 */

#define CONTEXT_INI_C

#include <math.h>

#include "global.h"

#include "ctx_tables.h"
#include "biariencode.h"
#include "memalloc.h"

#define DEFAULT_CTX_MODEL   0
#define RELIABLE_COUNT      32.0
#define FRAME_TYPES         4
#define FIXED               0


int    num_mb_per_slice;
int    number_of_slices;
int*** initialized;
int*** model_number;


double entropy    [128];
double probability[128] =
{
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  0.000000, 0.000000, 0.000000, 0.000000,    0.000000, 0.000000, 0.000000, 0.000000,
  //--------------------------------------------------------------------------------
  0.500000, 0.474609, 0.450507, 0.427629,    0.405912, 0.385299, 0.365732, 0.347159,
  0.329530, 0.312795, 0.296911, 0.281833,    0.267520, 0.253935, 0.241039, 0.228799,
  0.217180, 0.206151, 0.195682, 0.185744,    0.176312, 0.167358, 0.158859, 0.150792,
  0.143134, 0.135866, 0.128966, 0.122417,    0.116200, 0.110299, 0.104698, 0.099381,
  0.094334, 0.089543, 0.084996, 0.080680,    0.076583, 0.072694, 0.069002, 0.065498,
  0.062172, 0.059014, 0.056018, 0.053173,    0.050473, 0.047909, 0.045476, 0.043167,
  0.040975, 0.038894, 0.036919, 0.035044,    0.033264, 0.031575, 0.029972, 0.028450,
  0.027005, 0.025633, 0.024332, 0.023096,    0.021923, 0.020810, 0.019753, 0.018750
};



void create_context_memory (void)
{
  int k;
  int num_mb  = img->FrameSizeInMbs; // number of macroblocks for frame
  double log2 = log(2.0);

  num_mb_per_slice  = (params->slice_mode == 1 ? params->slice_argument : num_mb);
  number_of_slices  = (num_mb + num_mb_per_slice - 1) / num_mb_per_slice;
  get_mem3Dint(&initialized, 3, FRAME_TYPES, number_of_slices);
  //===== set all context sets as "uninitialized" =====
  memset(&initialized[0][0][0], 0, 3 * FRAME_TYPES * number_of_slices * sizeof(int));
  get_mem3Dint(&model_number, 3, FRAME_TYPES, number_of_slices);

  //----- init tables -----
  for( k=0; k<64; k++ )
  {
    probability[k] = 1.0 - probability[127-k];
    entropy    [k] = log (probability[      k]) / log2;
    entropy[127-k] = log (probability[127 - k]) / log2;
  }
}

void free_context_memory (void)
{
  free_mem3Dint(initialized);
  free_mem3Dint(model_number);
}


#define BIARI_CTX_INIT2(ii,jj,ctx,tab,num) \
{ \
  if ((img->type==I_SLICE)||(img->type==SI_SLICE))  \
  for (i=0; i<ii; i++) \
  for (j=0; j<jj; j++) \
  { \
    biari_init_context (&(ctx[i][j]), &(tab ## _I[num][i][j][0])); \
  } \
  else \
  for (i=0; i<ii; i++) \
  for (j=0; j<jj; j++) \
  { \
    biari_init_context (&(ctx[i][j]), &(tab ## _P[num][i][j][0])); \
  } \
}

#define BIARI_CTX_INIT1(jj,ctx,tab,num) \
{ \
  if ((img->type==I_SLICE)||(img->type==SI_SLICE))  \
  for (j=0; j<jj; j++) \
  { \
    biari_init_context (&(ctx[j]), &(tab ## _I[num][0][j][0])); \
  } \
  else \
  for (j=0; j<jj; j++) \
  { \
    biari_init_context (&(ctx[j]), &(tab ## _P[num][0][j][0])); \
  } \
}

void SetCtxModelNumber (void)
{
  int frame_field = img->field_picture;
  int img_type    = img->type;
  int ctx_number  = img->currentSlice->start_mb_nr / num_mb_per_slice;

  if(img->type==I_SLICE)
  {
    img->model_number=DEFAULT_CTX_MODEL;
    return;
  }
  if(params->context_init_method==FIXED)
  {
    img->model_number=params->model_number;
    return;
  }

  if (initialized [frame_field][img_type][ctx_number])
  {
    img->model_number = model_number[frame_field][img_type][ctx_number];
  }
  else if (ctx_number && initialized[frame_field][img_type][ctx_number-1])
  {
    img->model_number = model_number[frame_field][img_type][ctx_number-1];
  }
  else
  {
    img->model_number = DEFAULT_CTX_MODEL;
  }
}

void init_contexts (void)
{
  MotionInfoContexts*  mc = img->currentSlice->mot_ctx;
  TextureInfoContexts* tc = img->currentSlice->tex_ctx;
  int i, j;

  //--- motion coding contexts ---
  BIARI_CTX_INIT2 (3, NUM_MB_TYPE_CTX,   mc->mb_type_contexts,     INIT_MB_TYPE,    img->model_number);
  BIARI_CTX_INIT2 (2, NUM_B8_TYPE_CTX,   mc->b8_type_contexts,     INIT_B8_TYPE,    img->model_number);
  BIARI_CTX_INIT2 (2, NUM_MV_RES_CTX,    mc->mv_res_contexts,      INIT_MV_RES,     img->model_number);
  BIARI_CTX_INIT2 (2, NUM_REF_NO_CTX,    mc->ref_no_contexts,      INIT_REF_NO,     img->model_number);
  BIARI_CTX_INIT1 (   NUM_DELTA_QP_CTX,  mc->delta_qp_contexts,    INIT_DELTA_QP,   img->model_number);
#if ENABLE_FIELD_CTX
  BIARI_CTX_INIT1 (   NUM_MB_AFF_CTX,    mc->mb_aff_contexts,      INIT_MB_AFF,     img->model_number);
#endif
  BIARI_CTX_INIT1 (   NUM_TRANSFORM_SIZE_CTX,  mc->transform_size_contexts,    INIT_TRANSFORM_SIZE,   img->model_number);

  //--- texture coding contexts ---
  BIARI_CTX_INIT1 (                 NUM_IPR_CTX,  tc->ipr_contexts,     INIT_IPR,       img->model_number);
  BIARI_CTX_INIT1 (                 NUM_CIPR_CTX, tc->cipr_contexts,    INIT_CIPR,      img->model_number);
  BIARI_CTX_INIT2 (3,               NUM_CBP_CTX,  tc->cbp_contexts,     INIT_CBP,       img->model_number);
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_BCBP_CTX, tc->bcbp_contexts,    INIT_BCBP,      img->model_number);
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_MAP_CTX,  tc->map_contexts[0],  INIT_MAP,       img->model_number);
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_LAST_CTX, tc->last_contexts[0], INIT_LAST,      img->model_number);  
#if ENABLE_FIELD_CTX
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_MAP_CTX,  tc->map_contexts[1],  INIT_FLD_MAP,   img->model_number);
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_LAST_CTX, tc->last_contexts[1], INIT_FLD_LAST,  img->model_number);
#endif
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_ONE_CTX,  tc->one_contexts,     INIT_ONE,       img->model_number);
  BIARI_CTX_INIT2 (NUM_BLOCK_TYPES, NUM_ABS_CTX,  tc->abs_contexts,     INIT_ABS,       img->model_number);
}


double XRate (BiContextTypePtr ctx, const char* model)
{
  int     ctx_state, mod_state;
  double  weight, xr = 0.0;
  int     qp = imax(0, img->qp);

  weight    = dmin (1.0, (double)ctx->count/(double)RELIABLE_COUNT);

  mod_state = ((model[0]*qp)>>4)+model[1];
  mod_state = iClip3(0, 127, mod_state);
  ctx_state = (ctx->MPS ? 64+ctx->state : 63-ctx->state);

  xr -= weight * probability[    ctx_state] * entropy[    mod_state];
  xr -= weight * probability[127-ctx_state] * entropy[127-mod_state];

  return xr;
}

#define ADD_XRATE2(ii,jj,ctx,tab,num) \
{ \
  if      (img->type==I_SLICE)  \
  for (i=0; i<ii; i++) \
  for (j=0; j<jj; j++) \
  { \
    xr += XRate (&(ctx[i][j]), &(tab ## _I[num][i][j][0])); \
  } \
  else \
  for (i=0; i<ii; i++) \
  for (j=0; j<jj; j++) \
  { \
    xr += XRate (&(ctx[i][j]), &(tab ## _P[num][i][j][0])); \
  } \
}

#define ADD_XRATE1(jj,ctx,tab,num) \
{ \
  if      (img->type==I_SLICE)  \
  for (j=0; j<jj; j++) \
  { \
    xr += XRate (&(ctx[j]), &(tab ## _I[num][0][j][0])); \
  } \
  else \
  for (j=0; j<jj; j++) \
  { \
    xr += XRate (&(ctx[j]), &(tab ## _P[num][0][j][0])); \
  } \
}


void GetCtxModelNumber (int* mnumber, MotionInfoContexts* mc, TextureInfoContexts* tc)
{
  int     model, j, i;
  int     num_models = (img->type==I_SLICE ? NUM_CTX_MODELS_I : NUM_CTX_MODELS_P);
  double  xr, min_xr = 1e30;

  for (model=0; model<num_models; model++)
  {
    xr = 0.0;
    //--- motion coding contexts ---
    ADD_XRATE2 (3, NUM_MB_TYPE_CTX,   mc->mb_type_contexts,     INIT_MB_TYPE,   model);
    ADD_XRATE2 (2, NUM_B8_TYPE_CTX,   mc->b8_type_contexts,     INIT_B8_TYPE,   model);
    ADD_XRATE2 (2, NUM_MV_RES_CTX,    mc->mv_res_contexts,      INIT_MV_RES,    model);
    ADD_XRATE2 (2, NUM_REF_NO_CTX,    mc->ref_no_contexts,      INIT_REF_NO,    model);
    ADD_XRATE1 (   NUM_DELTA_QP_CTX,  mc->delta_qp_contexts,    INIT_DELTA_QP,  model);
#if ENABLE_FIELD_CTX
    ADD_XRATE1 (   NUM_MB_AFF_CTX,    mc->mb_aff_contexts,      INIT_MB_AFF,    model);
#endif
    ADD_XRATE1 (   NUM_TRANSFORM_SIZE_CTX,  mc->transform_size_contexts, INIT_TRANSFORM_SIZE,  model);

    //--- texture coding contexts ---
    ADD_XRATE1 (                  NUM_IPR_CTX,  tc->ipr_contexts,       INIT_IPR,       model);
    ADD_XRATE1 (                  NUM_CIPR_CTX, tc->cipr_contexts,      INIT_CIPR,      model);
    ADD_XRATE2 (3,                NUM_CBP_CTX,  tc->cbp_contexts,       INIT_CBP,       model);
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_BCBP_CTX, tc->bcbp_contexts,      INIT_BCBP,      model);
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_MAP_CTX,  tc->map_contexts[0],    INIT_MAP,       model);
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_LAST_CTX, tc->last_contexts[0],   INIT_LAST,      model);
#if ENABLE_FIELD_CTX
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_MAP_CTX,  tc->map_contexts[1],    INIT_FLD_MAP,   model);
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_LAST_CTX, tc->last_contexts[1],   INIT_FLD_LAST,  model);
#endif
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_ONE_CTX,  tc->one_contexts,       INIT_ONE,       model);
    ADD_XRATE2 (NUM_BLOCK_TYPES,  NUM_ABS_CTX,  tc->abs_contexts,       INIT_ABS,       model);

    if (xr<min_xr)
    {
      min_xr    = xr;
      *mnumber  = model;
    }
  }
}

#undef ADD_XRATE2
#undef ADD_XRATE1

void store_contexts (void)
{
  int frame_field = img->field_picture;
  int img_type    = img->type;
  int ctx_number  = img->currentSlice->start_mb_nr / num_mb_per_slice;

  if( params->context_init_method )
  {
    initialized [frame_field][img_type][ctx_number] = 1;
    GetCtxModelNumber (model_number[frame_field][img_type]+ctx_number, img->currentSlice->mot_ctx, img->currentSlice->tex_ctx);
  }
  else
  {
    // do nothing
  }
}


void update_field_frame_contexts (int field)
{
  int i, j;

  if (field)
  {
    // set frame contexts
    for (j=0; j<FRAME_TYPES; j++)
    {
      for (i=0; i<number_of_slices; i++)
      {
        initialized [0][j][i] = initialized [1][j][i>>1];
        model_number[0][j][i] = model_number[1][j][i>>1];
      }
    }
  }
  else
  {
    // set field contexts
    for (j=0; j<FRAME_TYPES; j++)
    {
      for (i=0; i<((number_of_slices+1)>>1); i++)
      {
        initialized [1][j][i] = initialized [0][j][i<<1];
        model_number[1][j][i] = model_number[0][j][i<<1];
      }
    }
  }
}

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