nal.c

davinci avs.......................................................

/*!
 ************************************************************************
 * \file  nal.c
 * \brief 
 *     NAL unit handling
 ************************************************************************
 */

#include <stdio.h>
#include <assert.h>
//#include <malloc.h>

#include "global.h"
#include "nalu.h"
#include "memalloc.h"


/*! 
 *************************************************************************************
 * \brief
 *    Allocates memory for a NALU
 *
 * \param buffersize
 *     size of NALU buffer 
 *
 * \return
 *    pointer to a NALU
 *************************************************************************************
 */
 

NALU_t *AllocNALU(int buffersize)
{
  NALU_t *n;

  if ((n = (NALU_t*)calloc (1, sizeof (NALU_t))) == NULL) no_mem_exit ("AllocNALU: n");

  if ((n->buf = (byte*)calloc (buffersize, sizeof (byte))) == NULL) no_mem_exit ("AllocNALU: n->buf");
  
  return n;
}


/*! 
 *************************************************************************************
 * \brief
 *    Frees a NALU
 *
 * \param n 
 *    NALU to be freed
 *
 *************************************************************************************
 */

void FreeNALU(NALU_t *n)
{
  if (n)
  {
    if (n->buf)
    {
      free(n->buf);
      n->buf=NULL;
    }
    free (n);
  }
}


/*! 
 *************************************************************************************
 * \brief
 *    Converts a NALU to an RBSP
 *
 * \param 
 *    nalu: nalu structure to be filled
 *
 * \return
 *    length of the RBSP in bytes
 *************************************************************************************
 */
int NALUtoRBSP (NALU_t *nalu)
{
  assert (nalu != NULL);


  nalu->len = EBSPtoRBSP (nalu->buf, nalu->len, 1) ; 

  return nalu->len ;
}

/*!
************************************************************************
* \brief
*    Converts Encapsulated Byte Sequence Packets to RBSP
* \param streamBuffer
*    pointer to data stream
* \param end_bytepos
*    size of data stream
* \param begin_bytepos
*    Position after beginning 
************************************************************************/


int EBSPtoRBSP(byte *streamBuffer, int end_bytepos, int begin_bytepos)
{
  int i, j, count;
  count = 0;
  
  if(end_bytepos < begin_bytepos)
    return end_bytepos;
  
  j = begin_bytepos;
  
  for(i = begin_bytepos; i < end_bytepos; i++) 
  { //starting from begin_bytepos to avoid header information

    streamBuffer[j] = streamBuffer[i];

    j++;
  }
  
  return j;
}