www.pudn.com > rm52c.rar > golomb_dec.c

/* 
*********************************************************************** 
* COPYRIGHT AND WARRANTY INFORMATION 
* 
* Copyright 2003, Advanced Audio Video Coding Standard, Part II 
* 
* DISCLAIMER OF WARRANTY 
* 
* These software programs are available to the users without any 
* license fee or royalty on an "as is" basis. The AVS 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 contributors or  
* the AVS be liable for any incidental, punitive, or consequential 
* damages of any kind whatsoever arising from the use of this program. 
* 
* This disclaimer of warranty extends to the user of this program 
* and user's customers, employees, agents, transferees, successors, 
* and assigns. 
* 
* The AVS does not represent or warrant that the program furnished 
* hereunder are free of infringement of any third-party patents. 
* Commercial implementations of AVS, including shareware, may be 
* subject to royalty fees to patent holders. Information regarding 
* the AVS patent policy is available from the AVS Web site at 
* http://www.avs.org.cn 
* 
* THIS IS NOT A GRANT OF PATENT RIGHTS - SEE THE AVS PATENT POLICY. 
************************************************************************ 
*/ 
 
/* 
************************************************************************************* 
* File name: golomb_dec.c 
* Function: Description 
* 
************************************************************************************* 
*/ 
 
#include  
#include "golomb_dec.h" 
#include "global.h" 
 
#if TRACE 
/* 
************************************************************************* 
* Function: 
* Input: 
* Output: 
* Return:  
* Attention: 
************************************************************************* 
*/ 
void encode_golomb_word(unsigned int symbol,unsigned int grad0,unsigned int max_levels,unsigned int *res_bits,unsigned int *res_len) 
{ 
  unsigned int level,res,numbits; 
  res=1UL<=res && level=max_levels) 
  { 
    if(symbol>=res) 
      symbol=res-1UL;  //crop if too large. 
  } 
  //set data bits 
  *res_bits=res|symbol; 
  *res_len=numbits; 
} 
 
void encode_multilayer_golomb_word(unsigned int symbol,const unsigned int *grad,const unsigned int *max_levels,unsigned int *res_bits,unsigned int *res_len) 
{ 
  unsigned accbits,acclen,bits,len,tmp; 
  accbits=acclen=0UL; 
  while(1) 
  { 
    encode_golomb_word(symbol,*grad,*max_levels,&bits,&len); 
    accbits=(accbits<>bit)&1UL) ; 
    bit = (bit-1UL) & 7UL ; 
    if(bit==7UL)byte=*(++rd); 
  } 
  *buffer=rd; 
  *bitoff=bit; 
  return (((1UL<frame_bitoffset; 
  buf = (unsigned char*)currStream->streamBuffer; 
  BitstreamLengthInBytes = currStream->bitstream_length; 
   
  bit=7UL-(frame_bitoffset&7); 
  read=buf+(frame_bitoffset>>3); 
   
  if(!( se->golomb_maxlevels&~0xFF )) 
  { 
    se->value1=decode_golomb_word(&read,&bit,se->golomb_grad,se->golomb_maxlevels); 
 
  } 
  else 
  { 
    for(i=0UL;i<4UL;i++) 
    { 
      grad[i]=(se->golomb_grad>>(i<<3))&0xFFUL; 
      max_lev[i]=(se->golomb_maxlevels>>(i<<3))&0xFFUL; 
    } 
    se->value1=decode_multilayer_golomb_word(&read,&bit,grad,max_lev); 
  } 
   
  se->len=(((read-buf)<<3)+(7-bit))-frame_bitoffset; 
   fprintf(p_trace, "********** decoded golomb code == (%3d)**********\n",  se->value1);    //modified by sunnan   
   
#if TRACE 
  if(!( se->golomb_maxlevels&~0xFF ))    //only bits 0-7 used? This means normal Golomb word. 
    encode_golomb_word(se->value1,se->golomb_grad,se->golomb_maxlevels,&(se->value2),&len); 
  else 
  { 
    for(i=0UL;i<4UL;i++) 
    { 
      grad[i]=(se->golomb_grad>>(i<<3))&0xFFUL; 
      max_lev[i]=(se->golomb_maxlevels>>(i<<3))&0xFFUL; 
    } 
    encode_multilayer_golomb_word(se->value1,grad,max_lev,&(se->value2),&len); 
  } 
   
  tracebits3("", se->len, se->value2, se->value1); 
#endif 
 
  se->value2=0; 
  currStream->frame_bitoffset += se->len; 
   
  return 1; 
}