uvlc.c

网络MPEG4IP流媒体开发源代码

/*
***********************************************************************
* COPYRIGHT AND WARRANTY INFORMATION
*
* Copyright 2001, International Telecommunications Union, Geneva
*
* DISCLAIMER OF WARRANTY
*
* These software programs are available to the user without any
* license fee or royalty on an "as is" basis. The ITU disclaims
* any and all warranties, whether express, implied, or
* statutory, including any implied warranties of merchantability
* or of fitness for a particular purpose.  In no event shall the
* contributor or the ITU be liable for any incidental, punitive, or
* consequential damages of any kind whatsoever arising from the
* use of these programs.
*
* This disclaimer of warranty extends to the user of these programs
* and user's customers, employees, agents, transferees, successors,
* and assigns.
*
* The ITU does not represent or warrant that the programs furnished
* hereunder are free of infringement of any third-party patents.
* Commercial implementations of ITU-T Recommendations, including
* shareware, may be subject to royalty fees to patent holders.
* Information regarding the ITU-T patent policy is available from
* the ITU Web site at http://www.itu.int.
*
* THIS IS NOT A GRANT OF PATENT RIGHTS - SEE THE ITU-T PATENT POLICY.
************************************************************************
*/

/*!
 ***************************************************************************
 * \file uvlc.c
 *
 * \brief
 *    UVLC table helper functions
 *
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *    - Inge Lille-Lang鴜               <[e-mail]>
 *    - Detlev Marpe                    <[e-mail]>
 *    - Stephan Wenger                  <[e-mail]>
 ***************************************************************************
 */
#include "contributors.h"


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

#include "elements.h"

/*!
 ************************************************************************
 * \brief
 *    n_linfo
 * \par Input:
 *    Number in the code table
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void n_linfo(int n, int *len,int *info)
{
  int i,nn;

  nn=(n+1)/2;

  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len= 2*i + 1;
  *info=n+1-(int)pow(2,i);
}

/*!
 ************************************************************************
 * \par Input:
 *    Number in the code table
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void n_linfo2(int n, int dummy, int *len,int *info)
{
  int i,nn;

  nn=(n+1)/2;

  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len= 2*i + 1;
  *info=n+1-(int)pow(2,i);
}

/*!
 ************************************************************************
 * \par Input:
 *    Number in the code table
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void intrapred_linfo(int ipred1, int ipred2, int *len,int *info)
{
  extern const int IPRED_ORDER[6][6];
  n_linfo(IPRED_ORDER[ipred1][ipred2],len,info);

}

/*!
 ************************************************************************
 * \par Input:
 *    Number in the code table
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void cbp_linfo_intra(int cbp, int dummy, int *len,int *info)
{
  extern const int NCBP[48][2];
  n_linfo(NCBP[cbp][0],len,info);
}


/*!
 ************************************************************************
 * \par Input:
 *    Number in the code table
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void cbp_linfo_inter(int cbp, int dummy, int *len,int *info)
{
  extern const int NCBP[48][2];
  n_linfo(NCBP[cbp][1],len,info);
}
/*!
 ************************************************************************
 * \par Input:
 *    delta quant
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void dquant_linfo(int dquant, int dummy, int *len,int *info)
{

  int i,n,sign,nn;

  sign=0;

  if (dquant <= 0)
  {
    sign=1;
  }
  n=abs(dquant) << 1;

  /*
  n+1 is the number in the code table.  Based on this we find length and info
  */

  nn=n/2;
  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len=i*2 + 1;
  *info=n - (int)pow(2,i) + sign;
}


/*!
 ************************************************************************
 * \par Input:
 *    motion vector differense
 * \par Output:
 *    lenght and info
 ************************************************************************
 */
void mvd_linfo2(int mvd, int dummy, int *len,int *info)
{

  int i,n,sign,nn;

  sign=0;

  if (mvd <= 0)
  {
    sign=1;
  }
  n=abs(mvd) << 1;

  /*
  n+1 is the number in the code table.  Based on this we find length and info
  */

  nn=n/2;
  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len=i*2 + 1;
  *info=n - (int)pow(2,i) + sign;
}


/*!
 ************************************************************************
 * \brief
 *    2x2 transform of chroma DC
 * \par Input:
 *    level and run for coefficiets
 * \par Output:
 *    lenght and info
 * \note
 *    see ITU document for bit assignment
 ************************************************************************
 */
void levrun_linfo_c2x2(int level,int run,int *len,int *info)
{
  const int NTAB[2][2]=
  {
    {1,5},
    {3,0}
  };
  const int LEVRUN[4]=
  {
    2,1,0,0
  };

  int levabs,i,n,sign,nn;

  if (level == 0) //  check if the coefficient sign EOB (level=0)
  {
    *len=1;
    return;
  }
  sign=0;
  if (level <= 0)
  {
    sign=1;
  }
  levabs=abs(level);
  if (levabs <= LEVRUN[run])
  {
    n=NTAB[levabs-1][run]+1;
  }
  else
  {
    n=(levabs-LEVRUN[run])*8 + run*2;
  }

  nn=n/2;

  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len= 2*i + 1;
  *info=n-(int)pow(2,i)+sign;
}

/*!
 ************************************************************************
 * \brief
 *    Single scan coefficients
 * \par Input:
 *    level and run for coefficiets
 * \par Output:
 *    lenght and info
 * \note
 *    see ITU document for bit assignment
 ************************************************************************
 */
void levrun_linfo_inter(int level,int run,int *len,int *info)
{
  const byte LEVRUN[16]=
  {
    4,2,2,1,1,1,1,1,1,1,0,0,0,0,0,0
  };
  const byte NTAB[4][10]=
  {
    { 1, 3, 5, 9,11,13,21,23,25,27},
    { 7,17,19, 0, 0, 0, 0, 0, 0, 0},
    {15, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {29, 0, 0, 0, 0, 0, 0, 0, 0, 0},
  };

  int levabs,i,n,sign,nn;

  if (level == 0)           //  check for EOB
  {
    *len=1;
    return;
  }

  if (level <= 0)
    sign=1;
  else
    sign=0;

  levabs=abs(level);
  if (levabs <= LEVRUN[run])
  {
    n=NTAB[levabs-1][run]+1;
  }
  else
  {
    n=(levabs-LEVRUN[run])*32 + run*2;
  }

  nn=n/2;

  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len= 2*i + 1;
  *info=n-(int)pow(2,i)+sign;

}

/*!
 ************************************************************************
 * \brief
 *    Double scan coefficients
 * \par Input:
 *    level and run for coefficiets
 * \par Output:
 *    lenght and info
 * \note
 *    see ITU document for bit assignment
 ************************************************************************
 */
void levrun_linfo_intra(int level,int run,int *len,int *info)
{
  const byte LEVRUN[8]=
  {
    9,3,1,1,1,0,0,0
  };

  const byte NTAB[9][5] =
  {
    { 1, 3, 7,15,17},
    { 5,19, 0, 0, 0},
    { 9,21, 0, 0, 0},
    {11, 0, 0, 0, 0},
    {13, 0, 0, 0, 0},
    {23, 0, 0, 0, 0},
    {25, 0, 0, 0, 0},
    {27, 0, 0, 0, 0},
    {29, 0, 0, 0, 0},
  };

  int levabs,i,n,sign,nn;

  if (level == 0)     //  check for EOB
  {
    *len=1;
    return;
  }
  if (level <= 0)
    sign=1;
  else
    sign=0;

  levabs=abs(level);
  if (levabs <= LEVRUN[run])
  {
    n=NTAB[levabs-1][run]+1;
  }
  else
  {
    n=(levabs-LEVRUN[run])*16 + 16 + run*2;
  }

  nn=n/2;

  for (i=0; i < 16 && nn != 0; i++)
  {
    nn /= 2;
  }
  *len= 2*i + 1;
  *info=n-(int)pow(2,i)+sign;
}

/*!
 ************************************************************************
 * \brief
 *    Makes code word and passes it back
 *    A code word has the following format: 0 Xn...0 X2 0 X1 0 X0 1
 *
 * \par Input:
 *    Info   : Xn..X2 X1 X0                                             \n
 *    Length : Total number of bits in the codeword
 ************************************************************************
 */

int symbol2uvlc(SyntaxElement *sym)
{
  int info_len = sym->len/2;

  // Convert info into a bitpattern int
  sym->bitpattern = 0;

  // vlc coding
  while(--info_len >= 0)
  {
    sym->bitpattern <<= 2;
    sym->bitpattern |= (0x01 & (sym->inf >> info_len));
  }
  sym->bitpattern <<= 1;
  sym->bitpattern |= 0x01;

  return 0;
}


/*!
 ************************************************************************
 * \brief
 *    generates UVLC code and passes the codeword to the buffer
 ************************************************************************
 */
int writeSyntaxElement_UVLC(SyntaxElement *se, DataPartition *this_dataPart)
{

  se->mapping(se->value1,se->value2,&(se->len),&(se->inf));

  symbol2uvlc(se);

  writeUVLC2buffer(se, this_dataPart->bitstream);

#if TRACE
  if(se->type <= 1)
    trace2out (se);
#endif

  return (se->len);
}


/*!
 ************************************************************************
 * \brief
 *    writes UVLC code to the appropriate buffer
 ************************************************************************
 */
void  writeUVLC2buffer(SyntaxElement *se, Bitstream *currStream)
{

  int i;
  unsigned int mask = 1 << (se->len-1);

  // Add the new bits to the bitstream.
  // Write out a byte if it is full
  for (i=0; i<se->len; i++)
  {
    currStream->byte_buf <<= 1;
    if (se->bitpattern & mask)
      currStream->byte_buf |= 1;
    currStream->bits_to_go--;
    mask >>= 1;
    if (currStream->bits_to_go==0)
    {
      currStream->bits_to_go = 8;
      currStream->streamBuffer[currStream->byte_pos++]=currStream->byte_buf;
    }
  }
}



/*!
 ************************************************************************
 * \brief
 *    generates UVLC code for EOS and writes it to the appropriate buffer
 ************************************************************************
 */
void  writeEOS2buffer()
{
  int dP_nr = assignSE2partition[input->partition_mode][SE_EOS];
  Bitstream *currStream = ((img->currentSlice)->partArr[dP_nr]).bitstream;

  SyntaxElement sym;

  sym.len = LEN_STARTCODE;
  sym.inf = EOS;
  sym.type  = SE_EOS;
#if TRACE
  strncpy(sym.tracestring, "EOS",TRACESTRING_SIZE);
#endif

  symbol2uvlc(&sym);

  writeUVLC2buffer(&sym, currStream);

#if TRACE
  trace2out(&sym);
#endif


}


/*!
 ************************************************************************
 * \brief
 *    Write out a trace string on the trace file
 ************************************************************************
 */
#if TRACE
void
trace2out(SyntaxElement *sym)
{
  static int bitcounter = 0;
  int i, chars;

  if (p_trace != NULL)
  {
    putc('@', p_trace);
    chars = fprintf(p_trace, "%i", bitcounter);
    while(chars++ < 6)
      putc(' ',p_trace);

    chars += fprintf(p_trace, "%s", sym->tracestring);
    while(chars++ < 50)
      putc(' ',p_trace);

  // Align bitpattern
    if(sym->len<15)
    {
      for(i=0 ; i<15-sym->len ; i++)
        fputc(' ', p_trace);
    }
    // Print bitpattern
    bitcounter += sym->len;
    for(i=1 ; i<=sym->len ; i++)
    {
      if((sym->bitpattern >> (sym->len-i)) & 0x1)
        fputc('1', p_trace);
      else
        fputc('0', p_trace);
    }
    fprintf(p_trace, "\n");
  }
  fflush (p_trace);
}
#endif