filehandle.c

MPEG-4编解码的实现(包括MPEG4视音频编解码)

/*
***********************************************************************
* 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
 *    filehandle.c
 * \brief
 *    Handles the operations how to write
 *    the generated symbols on the interim file format or some
 *    other specified output formats
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *      - Thomas Stockhammer            <[e-mail]>
 *      - Detlev Marpe                  <[e-mail]>
 ***************************************************************************************
 */

#include "contributors.h"

#include <string.h>
#include <math.h>
#include <time.h>
#include <sys/timeb.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

#include "global.h"
#include "header.h"
#include "rtp.h"


// Global Varibales

static FILE *out;   //!< output file

/*
   The implemented solution for a unified picture header
*/

/*!
 ************************************************************************
 * \brief
 *    Error handling procedure. Print error message to stderr and exit
 *    with supplied code.
 * \param text
 *    Error message
 * \param code
 *    Exit code
 ************************************************************************
 */
void error(char *text, int code)
{
  fprintf(stderr, "%s\n", text);
  exit(code);
}


/*!
 ************************************************************************
 * \brief
 *    This function opens the output files and generates the
 *    appropriate sequence header
 ************************************************************************
 */
int start_sequence()
{
  int len;

  switch(input->of_mode)
  {
    case PAR_OF_26L:
#ifndef H26L_LIB
      if ((out=fopen(input->outfile,"wb"))==NULL)
      {
          snprintf(errortext, ET_SIZE, "Error open file %s  \n",input->outfile);
          error(errortext,1);
      }
#endif
      len = SequenceHeader(out);
      return 0;
    case PAR_OF_RTP:
      if ((out=fopen(input->outfile,"wb"))==NULL)
      {
          snprintf(errortext, ET_SIZE, "Error open file %s  \n",input->outfile);
          error(errortext,1);
      }
      len = SequenceHeader(out);
      return len;
      
    default:
      snprintf(errortext, ET_SIZE, "Output File Mode %d not supported", input->of_mode);
      error(errortext,1);
      return 1;
  }
}

/*!
 ************************************************************************
 * \brief
 *     This function terminates the sequence and closes the
 *     output files
 ************************************************************************
 */
int terminate_sequence()
{
  Bitstream *currStream;

  // Mainly flushing of everything
  // Add termination symbol, etc.

  switch(input->of_mode)
  {
    case PAR_OF_26L:
      currStream = ((img->currentSlice)->partArr[0]).bitstream;
      if (input->symbol_mode == UVLC)
      {

        // Current TML File Format
        // Get the trailing bits of the last slice
        currStream->bits_to_go  = currStream->stored_bits_to_go;
        currStream->byte_pos    = currStream->stored_byte_pos;
        currStream->byte_buf    = currStream->stored_byte_buf;

        if (currStream->bits_to_go < 8)   // there are bits left in the last byte
          currStream->streamBuffer[currStream->byte_pos++] = currStream->byte_buf;
        // Write all remaining bits to output bitstream file
#ifdef H26L_LIB
        memcpy(&memout[memoutlength], currStream->streamBuffer, 
			currStream->byte_pos);
		memoutlength += currStream->byte_pos;
#else
        fwrite (currStream->streamBuffer, 1, currStream->byte_pos, out);
        fclose(out);
#endif
      }
      else
      {
        // CABAC File Format
        fclose(out);
      }
      return 0;
    case PAR_OF_RTP:
      fclose (out);
      return 0;
    default:
      snprintf(errortext, ET_SIZE, "Output File Mode %d not supported", input->of_mode);
      error(errortext,1);
      return 1;
  }
}

/*!
 ************************************************************************
 *  \brief
 *     This function generates the appropriate slice
 *     header
 *
 *  \return number of bits used for the picture header, including the PSC.
 *
 *  \par Side effects:
 *      Adds picture header symbols to the symbol buffer
 *
 *  \par Remarks:
 *      THIS IS AN INTERIM SOLUTION FOR A PICTURE HEADER, see VCEG-M79
 *                                                                               \par
 *      Generates the Picture Header out of the information in img_par and inp-par,
 *      and writes it to the symbol buffer.  The structure of the Picture Header
 *      is discussed in VCEG-M79.  It is implemented as discussed there.  In addition,
 *      it is preceeded by a picture start code, a UVLC-codeword of LEN=31 and INFO = 0.
 *      It would have been possible to put information into this codeword, similar
 *      to designs earlier than TML 5.9.  But it is deemed that the waste of 15
 *      data bits is acceptable considering the advantages of being able to search
 *      for a picture header quickly and easily, by looking for 30 consecutive, byte-
 *      aligned zero bits.
 *                                                                               \par
 *      The accounting of the header length (variable len) relies on the side effect
 *      of writeUVLCSymbol() that sets len and info in the symbol variable parameter
 ************************************************************************
*/

int start_slice(SyntaxElement *sym)
{
  EncodingEnvironmentPtr eep;
  Slice *currSlice = img->currentSlice;
  Bitstream *currStream;
  int header_len;
  int i;

  switch(input->of_mode)
  {
    case PAR_OF_26L:
      if (input->symbol_mode == UVLC)
      {
        currStream = (currSlice->partArr[0]).bitstream;
        // the information given in the SliceHeader is far not enought if we want to be able
        // to do some errorconcealment.
        // So write PictureHeader and SliceHeader in any case.
       header_len = PictureHeader();   // Picture Header
       header_len += SliceHeader (0);  // Slice Header without Start Code
       
        return header_len;
      }
      else
      {                   // H.26: CABAC File Format
        eep = &((currSlice->partArr[0]).ee_cabac);
        currStream = (currSlice->partArr[0]).bitstream;

        assert (currStream->bits_to_go == 8);
        assert (currStream->byte_buf == 0);
        assert (currStream->byte_pos == 0);
        memset(currStream->streamBuffer, 0, 12);    // fill first 12 bytes with zeros (debug only)

        // the information given in the SliceHeader is far not enought if we want to be able
        // to do some errorconcealment.
        // So write PictureHeader and SliceHeader in any case.
        header_len = PictureHeader();   // Picture Header
        header_len += SliceHeader (0);  // Slice Header without Start Code
        
        // Note that PictureHeader() and SliceHeader() set the buffer pointers as a side effect
        // Hence no need for adjusting it manually (and preserving space to be patched later

        // reserve bits for d_MB_Nr
        currStream->header_len = header_len;
        currStream->header_byte_buffer = currStream->byte_buf;

        currStream->byte_pos += ((31-currStream->bits_to_go)/8);
        if ((31-currStream->bits_to_go)%8 != 0)
          currStream->byte_pos++;
        currStream->bits_to_go = 8;
        currStream->byte_pos++;

        // If there is an absolute need to communicate the partition size, this would be
        // the space to insert it
        arienco_start_encoding(eep, currStream->streamBuffer, &(currStream->byte_pos));
        // initialize context models
        init_contexts_MotionInfo(currSlice->mot_ctx, 1);
        init_contexts_TextureInfo(currSlice->tex_ctx, 1);

        return header_len;

      }
    
    case PAR_OF_RTP:
      if (img->current_mb_nr == 0)                       // new picture
        RTPUpdateTimestamp (img->tr);

      if (input->symbol_mode == UVLC)
      {
        header_len=RTPSliceHeader();                      // generate the slice header
        currStream = currSlice->partArr[0].bitstream;
        
        if (header_len % 8 != 0)
        {
          currStream->byte_buf <<= currStream->bits_to_go;
          currStream->bits_to_go=8;
          currStream->streamBuffer[currStream->byte_pos++]=currStream->byte_buf;
          currStream->byte_buf=0;
        }
        return header_len;
      }
      else