uvg266/src/cabac.c

/**
 *  HEVC Encoder
 *  - Marko Viitanen ( fador at iki.fi ), Tampere University of Technology, Department of Pervasive Computing.
 */

/*! \file cabac.c
    \brief CABAC
    \author Marko Viitanen
    \date 2012-06
    
    Content-adaptive binary arithmetic coder
*/

#include "cabac.h"

#include <stdlib.h>
#include <stdio.h>
#include <math.h>


const uint8_t g_aucNextStateMPS[ 128 ] =
{
    2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,
   18,  19,  20,  21,  22,  23,  24,  25,  26,  27,  28,  29,  30,  31,  32,  33,
   34,  35,  36,  37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,  49,
   50,  51,  52,  53,  54,  55,  56,  57,  58,  59,  60,  61,  62,  63,  64,  65,
   66,  67,  68,  69,  70,  71,  72,  73,  74,  75,  76,  77,  78,  79,  80,  81,
   82,  83,  84,  85,  86,  87,  88,  89,  90,  91,  92,  93,  94,  95,  96,  97,
   98,  99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113,
  114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 124, 125, 126, 127
};

const uint8_t g_aucNextStateLPS[ 128 ] =
{
  1,  0,   0,  1,  2,  3,  4,  5,  4,  5,  8,  9,  8,  9,  10,  11,
  12, 13, 14, 15, 16, 17, 18, 19, 18, 19, 22, 23, 22, 23,  24,  25,
  26, 27, 26, 27, 30, 31, 30, 31, 32, 33, 32, 33, 36, 37,  36,  37,
  38, 39, 38, 39, 42, 43, 42, 43, 44, 45, 44, 45, 46, 47,  48,  49,
  48, 49, 50, 51, 52, 53, 52, 53, 54, 55, 54, 55, 56, 57,  58,  59,
  58, 59, 60, 61, 60, 61, 60, 61, 62, 63, 64, 65, 64, 65,  66,  67,
  66, 67, 66, 67, 68, 69, 68, 69, 70, 71, 70, 71, 70, 71,  72,  73,
  72, 73, 72, 73, 74, 75, 74, 75, 74, 75, 76, 77, 76, 77, 126, 127
};

const uint8_t g_aucLPSTable[64][4] =
{
  {128, 176, 208, 240},  {128, 167, 197, 227},  {128, 158, 187, 216},  {123, 150, 178, 205},  {116, 142, 169, 195},
  {111, 135, 160, 185},  {105, 128, 152, 175},  {100, 122, 144, 166},  { 95, 116, 137, 158},  { 90, 110, 130, 150},
  { 85, 104, 123, 142},  { 81,  99, 117, 135},  { 77,  94, 111, 128},  { 73,  89, 105, 122},  { 69,  85, 100, 116},
  { 66,  80,  95, 110},  { 62,  76,  90, 104},  { 59,  72,  86,  99},  { 56,  69,  81,  94},  { 53,  65,  77,  89},
  { 51,  62,  73,  85},  { 48,  59,  69,  80},  { 46,  56,  66,  76},  { 43,  53,  63,  72},  { 41,  50,  59,  69},
  { 39,  48,  56,  65},  { 37,  45,  54,  62},  { 35,  43,  51,  59},  { 33,  41,  48,  56},  { 32,  39,  46,  53},
  { 30,  37,  43,  50},  { 29,  35,  41,  48},  { 27,  33,  39,  45},  { 26,  31,  37,  43},  { 24,  30,  35,  41},
  { 23,  28,  33,  39},  { 22,  27,  32,  37},  { 21,  26,  30,  35},  { 20,  24,  29,  33},  { 19,  23,  27,  31},
  { 18,  22,  26,  30},  { 17,  21,  25,  28},  { 16,  20,  23,  27},  { 15,  19,  22,  25},  { 14,  18,  21,  24},
  { 14,  17,  20,  23},  { 13,  16,  19,  22},  { 12,  15,  18,  21},  { 12,  14,  17,  20},  { 11,  14,  16,  19},
  { 11,  13,  15,  18},  { 10,  12,  15,  17},  { 10,  12,  14,  16},  {  9,  11,  13,  15},  {  9,  11,  12,  14},
  {  8,  10,  12,  14},  {  8,   9,  11,  13},  {  7,   9,  11,  12},  {  7,   9,  10,  12},  {  7,   8,  10,  11},
  {  6,   8,   9,  11},  {  6,   7,   9,  10},  {  6,   7,   8,   9},  {  2,   2,   2,   2}
};

const uint8_t g_aucRenormTable[32] = {  6, 5, 4, 4, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2,
                                        1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};


uint8_t g_nextState[128][2];

cabac_data cabac;


void ctx_init(cabac_ctx* ctx, uint32_t qp, uint32_t initValue )
{
  int  slope       = (initValue>>4)*5 - 45;
  int  offset      = ((initValue&15)<<3)-16;
  int  initState   =  MIN( MAX( 1, ( ( ( slope * (int)qp ) >> 4 ) + offset ) ), 126 );
  uint8_t mpState  = (initState >= 64 )?1:0;
  ctx->ucState     = ( (mpState? (initState - 64):(63 - initState)) <<1) + mpState;
  ctx->binsCoded   = 0;
}


void ctx_buildNextStateTable()
{
  int i,j;
  for (i = 0; i < 128; i++)
  {
    for (j = 0; j < 2; j++)
    {
      g_nextState[i][j] = ((i&1) == j) ? g_aucNextStateMPS[i] : g_aucNextStateLPS[i];
    }
  }
}

INLINE void ctx_update(cabac_ctx* ctx, int val ) { ctx->ucState = g_nextState[ctx->ucState][val]; }
//void ctx_update_LPS(cabac_ctx* ctx) { ctx->ucState = g_aucNextStateLPS[ ctx->ucState ]; }
//void ctx_update_MPS(cabac_ctx* ctx) { ctx->ucState = g_aucNextStateMPS[ ctx->ucState ]; }

void cabac_init(cabac_data* data)
{
  data->fracBits = 0;
  data->binCountIncrement = 0;
  data->uiBinsCoded = 0;
  ctx_buildNextStateTable();
}

void cabac_start(cabac_data* data)
{
  data->uiLow            = 0;
  data->uiRange          = 510;
  data->bitsLeft         = 23;
  data->numBufferedBytes = 0;
  data->bufferedByte     = 0xff;
}

void cabac_encodeBin(cabac_data* data, uint32_t binValue )
{
  uint32_t uiLPS;
  //printf("\tdecodeBin m_uiRange %d uivalue %d\n", data->uiRange, data->uiLow);
  data->uiBinsCoded += data->binCountIncrement;
  data->ctx->binsCoded = 1;
  
  uiLPS   = g_aucLPSTable[ CTX_STATE(data->ctx) ][ ( data->uiRange >> 6 ) & 3 ];
  data->uiRange    -= uiLPS;
  #ifdef _DEBUG
  //printf("\tencodeBin m_uiRange %d uiLPS %d m_uiValue %d ", data->uiRange,uiLPS,data->uiLow);
  #endif
  
  //Not the Most Probable Symbol?
  if( binValue != CTX_MPS(data->ctx) )
  {
    int numBits   = g_aucRenormTable[ uiLPS >> 3 ];
    data->uiLow   = ( data->uiLow + data->uiRange ) << numBits;
    data->uiRange = uiLPS << numBits;
    
    ctx_update_LPS(data->ctx);
    
    data->bitsLeft -= numBits;
  }
  else
  {
    ctx_update_MPS(data->ctx);
    if (  data->uiRange >= 256 )
    {
      #ifdef _DEBUG
      //printf("enduiValue %d \n",data->uiLow);
      #endif
      return;
    }
    
    data->uiLow <<= 1;
    data->uiRange <<= 1;
    data->bitsLeft--;
  }
  
  if(data->bitsLeft < 12)
  {
    cabac_write(data);
  }
  #ifdef _DEBUG
  //printf("enduiValue %d \n",data->uiLow);
  #endif
}

void cabac_write(cabac_data* data)
{
  uint32_t leadByte = data->uiLow >> (24 - data->bitsLeft);
  data->bitsLeft += 8;
  data->uiLow &= 0xffffffffu >> data->bitsLeft;
  
  if ( leadByte == 0xff )
  {
    data->numBufferedBytes++;
  }
  else
  {
    if ( data->numBufferedBytes > 0 )
    {
      uint32_t carry = leadByte >> 8;
      uint32_t byte = data->bufferedByte + carry;
      data->bufferedByte = leadByte & 0xff;
      bitstream_put(data->stream,byte,8);

      byte = ( 0xff + carry ) & 0xff;
      while ( data->numBufferedBytes > 1 )
      {
        bitstream_put(data->stream,byte,8);
        data->numBufferedBytes--;
      }
    }
    else
    {
      data->numBufferedBytes = 1;
      data->bufferedByte = leadByte;
    }
  }
}

void cabac_finish(cabac_data* data)
{
  if ( data->uiLow >> ( 32 - data->bitsLeft ) )
  {
    bitstream_put(data->stream,data->bufferedByte + 1, 8 );
    while ( data->numBufferedBytes > 1 )
    {
      bitstream_put(data->stream,0, 8 );
      data->numBufferedBytes--;
    }
    data->uiLow -= 1 << ( 32 - data->bitsLeft );
  }
  else
  {
    if ( data->numBufferedBytes > 0 )
    {
      bitstream_put(data->stream,data->bufferedByte, 8 );
    }
    while ( data->numBufferedBytes > 1 )
    {
      bitstream_put(data->stream, 0xff, 8 );
      data->numBufferedBytes--;
    }
  }
  bitstream_put(data->stream, data->uiLow >> 8, 24 - data->bitsLeft );
}

/*!
  \brief Encode terminating bin
  \param binValue bin value
*/
void cabac_encodeBinTrm(cabac_data* data, uint8_t binValue )
{
  #ifdef _DEBUG
  //printf("\tencodeBinTrm m_uiRange %d uivalue %d\n", data->uiRange, data->uiLow);
  #endif
  data->uiBinsCoded += data->binCountIncrement;
  data->uiRange -= 2;
  if( binValue )
  {
    data->uiLow  += data->uiRange;
    data->uiLow <<= 7;
    data->uiRange = 2 << 7;
    data->bitsLeft -= 7;
  }
  else if ( data->uiRange >= 256 )
  {
    return;
  }
  else
  {
    data->uiLow   <<= 1;
    data->uiRange <<= 1;
    data->bitsLeft--;
  }
  
  if(data->bitsLeft < 12)
  {
    cabac_write(data);
  }
}

void cabac_flush(cabac_data* data)
{
  cabac_encodeBinTrm(data,1);
  cabac_finish(data);
  bitstream_put(data->stream,1,1);
  bitstream_align_zero(data->stream);
  cabac_start(data);
}

void cabac_encodeBinEP(cabac_data* data, uint32_t binValue )
{
  data->uiBinsCoded += data->binCountIncrement;
  data->uiLow <<= 1;
  if( binValue )
  {
    data->uiLow += data->uiRange;
  }
  data->bitsLeft--;

  if(data->bitsLeft < 12)
  {
    cabac_write(data);
  }
}

void cabac_encodeBinsEP(cabac_data* data, uint32_t binValues, int numBins )
{
  uint32_t pattern;
  data->uiBinsCoded += numBins & -data->binCountIncrement;

  while ( numBins > 8 )
  {
    numBins -= 8;
    pattern = binValues >> numBins;
    data->uiLow <<= 8;
    data->uiLow += data->uiRange * pattern;
    binValues -= pattern << numBins;
    data->bitsLeft -= 8;
    
    if(data->bitsLeft < 12)
    {
      cabac_write(data);
    }
  }
  
  data->uiLow <<= numBins;
  data->uiLow += data->uiRange * binValues;
  data->bitsLeft -= numBins;
  
  if(data->bitsLeft < 12)
  {
    cabac_write(data);
  }
}



/*!
  \brief Coding of coeff_abs_level_minus3
  \param uiSymbol value of coeff_abs_level_minus3
  \param ruiGoRiceParam reference to Rice parameter
  \returns Void
*/
void cabac_writeCoeffRemain(cabac_data* cabac,uint32_t symbol, uint32_t rParam )
{
  int32_t codeNumber = symbol;
  uint32_t length;
  if (codeNumber < (3 << rParam))
  {
    length = codeNumber>>rParam;
    cabac_encodeBinsEP(cabac, (1<<(length+1))-2 , length+1);
    cabac_encodeBinsEP(cabac,(codeNumber%(1<<rParam)),rParam);
  }
  else
  {
    length = rParam;
    codeNumber  = codeNumber - ( 3 << rParam);
    while (codeNumber >= (1<<length))
    {
      codeNumber -=  (1<<(length++));    
    }
    cabac_encodeBinsEP(cabac,(1<<(3+length+1-rParam))-2,3+length+1-rParam);
    cabac_encodeBinsEP(cabac,codeNumber,length);
  }
}

void cabac_writeUnaryMaxSymbol(cabac_data* data,cabac_ctx* ctx, uint32_t uiSymbol,int32_t iOffset, uint32_t uiMaxSymbol)
{
  int8_t bCodeLast = ( uiMaxSymbol > uiSymbol );

  if (!uiMaxSymbol)  
    return;
  
  data->ctx = &ctx[0];
  cabac_encodeBin(data, uiSymbol ? 1 : 0);
  
  if (!uiSymbol)
    return;
  
  while( --uiSymbol )
  {
    data->ctx = &ctx[iOffset];
    cabac_encodeBin(data, 1);
  }
  if( bCodeLast )
  {
    data->ctx = &ctx[iOffset];
    cabac_encodeBin(data, 0);
  }
  
  return;
}

void cabac_writeEpExGolomb(cabac_data* data, uint32_t uiSymbol, uint32_t uiCount )
{
  uint32_t bins = 0;
  int32_t numBins = 0;
  
  while( uiSymbol >= (uint32_t)(1<<uiCount) )
  {
    bins = 2 * bins + 1;
    numBins++;
    uiSymbol -= 1 << uiCount;
    uiCount  ++;
  }
  bins = 2 * bins + 0;
  numBins++;
  
  bins = (bins << uiCount) | uiSymbol;
  numBins += uiCount;
  
  cabac_encodeBinsEP(data, bins, numBins);
}