vlc.c

此code含H.264解码需要的 lib和 src

/*!
 ************************************************************************
 * \file vlc.c
 *
 * \brief
 *    VLC support functions
 *
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *    - Inge Lille-Lang鴜               <[e-mail]>
 *    - Detlev Marpe                    <[e-mail]>
 *    - Gabi Blaettermann
 ************************************************************************
 */
//#include "contributors.h"

#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <assert.h>

#include "global.h"
#include "vlc.h"
#include "elements.h"


// A little trick to avoid those horrible #if TRACE all over the source code
#if TRACE
#define SYMTRACESTRING(s) strncpy(symbol.tracestring,s,TRACESTRING_SIZE)
#else
#define SYMTRACESTRING(s) // do nothing
#endif

extern void tracebits(const char *trace_str,  int len,  int info,int value1);


int UsedBits;      // for internal statistics, is adjusted by se_v, ue_v, u_1

// Note that all NA values are filled with 0

//! for the linfo_levrun_inter routine
const byte NTAB1[4][8][2] =
{
  {{1,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}},
  {{1,1},{1,2},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}},
  {{2,0},{1,3},{1,4},{1,5},{0,0},{0,0},{0,0},{0,0}},
  {{3,0},{2,1},{2,2},{1,6},{1,7},{1,8},{1,9},{4,0}},
};
const byte LEVRUN1[16]=
{
  4,2,2,1,1,1,1,1,1,1,0,0,0,0,0,0,
};


const byte NTAB2[4][8][2] =
{
  {{1,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}},
  {{1,1},{2,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}},
  {{1,2},{3,0},{4,0},{5,0},{0,0},{0,0},{0,0},{0,0}},
  {{1,3},{1,4},{2,1},{3,1},{6,0},{7,0},{8,0},{9,0}},
};

//! for the linfo_levrun__c2x2 routine
const byte LEVRUN3[4] =
{
  2,1,0,0
};
const byte NTAB3[2][2][2] =
{
  {{1,0},{0,0}},
  {{2,0},{1,1}},
};

/*!
 *************************************************************************************
 * \brief
 *    ue_v, reads an ue(v) syntax element, the length in bits is stored in
 *    the global UsedBits variable
 *
 * \param tracestring
 *    the string for the trace file
 *
 * \param bitstream
 *    the stream to be read from
 *
 * \return
 *    the value of the coded syntax element
 *
 *************************************************************************************
 */
int ue_v (char *tracestring, Bitstream *bitstream)
{
  SyntaxElement symbol;

  assert (bitstream->streamBuffer != NULL);
  symbol.type = SE_HEADER;
  symbol.mapping = linfo_ue;   // Mapping rule
  SYMTRACESTRING(tracestring);
  readSyntaxElement_VLC (&symbol, bitstream);
  UsedBits+=symbol.len;
  return symbol.value1;
}


/*!
 *************************************************************************************
 * \brief
 *    ue_v, reads an se(v) syntax element, the length in bits is stored in
 *    the global UsedBits variable
 *
 * \param tracestring
 *    the string for the trace file
 *
 * \param bitstream
 *    the stream to be read from
 *
 * \return
 *    the value of the coded syntax element
 *
 *************************************************************************************
 */
int se_v (char *tracestring, Bitstream *bitstream)
{
  SyntaxElement symbol;

  assert (bitstream->streamBuffer != NULL);
  symbol.type = SE_HEADER;
  symbol.mapping = linfo_se;   // Mapping rule: signed integer
  SYMTRACESTRING(tracestring);
  readSyntaxElement_VLC (&symbol, bitstream);
  UsedBits+=symbol.len;
  return symbol.value1;
}


/*!
 *************************************************************************************
 * \brief
 *    ue_v, reads an u(v) syntax element, the length in bits is stored in
 *    the global UsedBits variable
 *
 * \param LenInBits
 *    length of the syntax element
 *
 * \param tracestring
 *    the string for the trace file
 *
 * \param bitstream
 *    the stream to be read from
 *
 * \return
 *    the value of the coded syntax element
 *
 *************************************************************************************
 */
int u_v (int LenInBits, char*tracestring, Bitstream *bitstream)
{
  SyntaxElement symbol;
  symbol.inf = 0;

  assert (bitstream->streamBuffer != NULL);
  symbol.type = SE_HEADER;
  symbol.mapping = linfo_ue;   // Mapping rule
  symbol.len = LenInBits;
  SYMTRACESTRING(tracestring);
  readSyntaxElement_FLC (&symbol, bitstream);
  UsedBits+=symbol.len;
  return symbol.inf;
}

/*!
 *************************************************************************************
 * \brief
 *    i_v, reads an i(v) syntax element, the length in bits is stored in
 *    the global UsedBits variable
 *
 * \param LenInBits
 *    length of the syntax element
 *
 * \param tracestring
 *    the string for the trace file
 *
 * \param bitstream
 *    the stream to be read from
 *
 * \return
 *    the value of the coded syntax element
 *
 *************************************************************************************
 */
int i_v (int LenInBits, char*tracestring, Bitstream *bitstream)
{
  SyntaxElement symbol;

  symbol.inf = 0;

  assert (bitstream->streamBuffer != NULL);
  symbol.type = SE_HEADER;
  symbol.mapping = linfo_ue;   // Mapping rule
  symbol.len = LenInBits;
  SYMTRACESTRING(tracestring);
  readSyntaxElement_FLC (&symbol, bitstream);
  UsedBits+=symbol.len;

  // can be negative
  symbol.inf = -( symbol.inf & (1 << (LenInBits - 1)) ) | symbol.inf;

  return symbol.inf;
}


/*!
 *************************************************************************************
 * \brief
 *    ue_v, reads an u(1) syntax element, the length in bits is stored in
 *    the global UsedBits variable
 *
 * \param tracestring
 *    the string for the trace file
 *
 * \param bitstream
 *    the stream to be read from
 *
 * \return
 *    the value of the coded syntax element
 *
 *************************************************************************************
 */
Boolean u_1 (char *tracestring, Bitstream *bitstream)
{
  return (Boolean) u_v (1, tracestring, bitstream);
}



/*!
 ************************************************************************
 * \brief
 *    mapping rule for ue(v) syntax elements
 * \par Input:
 *    lenght and info
 * \par Output:
 *    number in the code table
 ************************************************************************
 */
void linfo_ue(int len, int info, int *value1, int *dummy)
{
  assert ((len >> 1) < 32);
  *value1 = (1 << (len >> 1)) + info - 1;
}

/*!
 ************************************************************************
 * \brief
 *    mapping rule for se(v) syntax elements
 * \par Input:
 *    lenght and info
 * \par Output:
 *    signed mvd
 ************************************************************************
 */
void linfo_se(int len,  int info, int *value1, int *dummy)
{
  int n;
  assert ((len >> 1) < 32);
  n = (1 << (len >> 1)) + info - 1;
  *value1 = (n + 1) >> 1;
  if((n & 0x01) == 0)                           // lsb is signed bit
    *value1 = -*value1;
}


/*!
 ************************************************************************
 * \par Input:
 *    length and info
 * \par Output:
 *    cbp (intra)
 ************************************************************************
 */
//void linfo_cbp_intra(int len,int info,int *cbp, int *dummy)
//{
//  extern const byte NCBP[2][48][2];
//  int cbp_idx;
//
//  linfo_ue(len, info, &cbp_idx, dummy);
//  *cbp = NCBP[active_sps->chroma_format_idc ? 1 : 0][cbp_idx][0];
//}

/*!
 ************************************************************************
 * \par Input:
 *    length and info
 * \par Output:
 *    cbp (inter)
 ************************************************************************
 */
//void linfo_cbp_inter(int len,int info,int *cbp, int *dummy)
//{
//  extern const byte NCBP[2][48][2];
//  int cbp_idx;
//
//  linfo_ue(len, info, &cbp_idx, dummy);
//  *cbp = NCBP[active_sps->chroma_format_idc ? 1 : 0][cbp_idx][1];
//}

/*!
 ************************************************************************
 * \par Input:
 *    length and info
 * \par Output:
 *    level, run
 ************************************************************************
 */
//void linfo_levrun_inter(int len, int info, int *level, int *irun)
//{
//  int l2;
//  int inf;
//  assert (((len>>1)-5)<32);
//  if (len<=9)
//  {
//    l2     = imax(0,(len >> 1)-1);
//    inf    = info >> 1;
//    *level = NTAB1[l2][inf][0];
//    *irun  = NTAB1[l2][inf][1];
//    if ((info & 0x01) == 1)
//      *level = -*level;                   // make sign
//  }
//  else                                  // if len > 9, skip using the array
//  {
//    *irun  = (info & 0x1e) >> 1;
//    *level = LEVRUN1[*irun] + (info >> 5) + ( 1 << ((len >> 1) - 5));
//    if ((info & 0x01) == 1)
//      *level = -*level;
//  }
//  if (len == 1) // EOB
//    *level = 0;
//}


/*!
 ************************************************************************
 * \par Input:
 *    length and info
 * \par Output:
 *    level, run
 ************************************************************************
 */
//void linfo_levrun_c2x2(int len, int info, int *level, int *irun)
//{
//  int l2;
//  int inf;
//
//  if (len<=5)
//  {
//    l2     = imax(0, (len >> 1) - 1);
//    inf    = info >> 1;
//    *level = NTAB3[l2][inf][0];
//    *irun  = NTAB3[l2][inf][1];
//    if ((info & 0x01) == 1)
//      *level = -*level;                 // make sign
//  }
//  else                                  // if len > 5, skip using the array
//  {
//    *irun  = (info & 0x06) >> 1;
//    *level = LEVRUN3[*irun] + (info >> 3) + (1 << ((len >> 1) - 3));
//    if ((info & 0x01) == 1)
//      *level = -*level;
//  }
//  if (len == 1) // EOB
//    *level = 0;
//}

/*!
 ************************************************************************
 * \brief
 *    read next UVLC codeword from UVLC-partition and
 *    map it to the corresponding syntax element
 ************************************************************************
 */
int readSyntaxElement_VLC(SyntaxElement *sym, Bitstream *currStream)
{
  int frame_bitoffset        = currStream->frame_bitoffset;
  int BitstreamLengthInBytes = currStream->bitstream_length;
  byte *buf                  = currStream->streamBuffer;

  sym->len =  GetVLCSymbol (buf, frame_bitoffset, &(sym->inf), BitstreamLengthInBytes);
  if (sym->len == -1)
    return -1;
  currStream->frame_bitoffset += sym->len;
  sym->mapping(sym->len,sym->inf,&(sym->value1),&(sym->value2));

#if TRACE
  tracebits(sym->tracestring, sym->len, sym->inf, sym->value1);
#endif

  return 1;
}


/*!
 ************************************************************************
 * \brief
 *    read next UVLC codeword from UVLC-partition and
 *    map it to the corresponding syntax element
 ************************************************************************
 */
//int readSyntaxElement_UVLC(SyntaxElement *sym, struct img_par *img, struct datapartition *dP)
//{
//  return (readSyntaxElement_VLC(sym, dP->bitstream));
//}

/*!
 ************************************************************************
 * \brief
 *    read next VLC codeword for 4x4 Intra Prediction Mode and
 *    map it to the corresponding Intra Prediction Direction
 ************************************************************************
 */
//int readSyntaxElement_Intra4x4PredictionMode(SyntaxElement *sym, struct img_par *img,struct datapartition *dP)
//{
//  Bitstream   *currStream            = dP->bitstream;
//  int         frame_bitoffset        = currStream->frame_bitoffset;
//  int         BitstreamLengthInBytes = currStream->bitstream_length;
//  byte        *buf                   = currStream->streamBuffer;
//
//  sym->len = GetVLCSymbol_IntraMode (buf, frame_bitoffset, &(sym->inf), BitstreamLengthInBytes);
//
//  if (sym->len == -1)
//    return -1;
//
//  currStream->frame_bitoffset += sym->len;
//  sym->value1                  = sym->len == 1 ? -1 : sym->inf;
//
//#if TRACE
//  tracebits2(sym->tracestring, sym->len, sym->value1);
//#endif
//
//  return 1;
//}

//int GetVLCSymbol_IntraMode (byte buffer[],int totbitoffset,int *info, int bytecount)
//{
//
//  register int inf;
//  long byteoffset = (totbitoffset >> 3);        // byte from start of buffer
//  int bitoffset   = (7 - (totbitoffset & 0x07)); // bit from start of byte
//  byte *cur_byte  = &(buffer[byteoffset]);
//  int ctr_bit     = (*cur_byte & (0x01 << bitoffset));      // control bit for current bit posision
//  int bitcounter  = 1;
//  int len         = 0;
//
//  //First bit
//  if (ctr_bit)
//  {
//    *info = 0;
//    return bitcounter;
//  }
//  else
//    len = 3;
//
//  if (byteoffset + ((len + 7) >> 3) > bytecount)