stsz.c

这个库实现了录象功能

/*******************************************************************************
 stsz.c

 libquicktime - A library for reading and writing quicktime/avi/mp4 files.
 http://libquicktime.sourceforge.net

 Copyright (C) 2002 Heroine Virtual Ltd.
 Copyright (C) 2002-2007 Members of the libquicktime project.

 This library is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free
 Software Foundation; either version 2.1 of the License, or (at your option)
 any later version.

 This library is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along
 with this library; if not, write to the Free Software Foundation, Inc., 51
 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*******************************************************************************/ 

#include "lqt_private.h"
#include <stdlib.h>

void quicktime_stsz_init(quicktime_stsz_t *stsz)
{
	stsz->version = 0;
	stsz->flags = 0;
	stsz->sample_size = 0;
	stsz->total_entries = 0;
	stsz->entries_allocated = 0;
}

void quicktime_stsz_init_video(quicktime_t *file, quicktime_stsz_t *stsz)
{
	stsz->sample_size = 0;
	if(!stsz->entries_allocated)
	{
		stsz->entries_allocated = 2048;
		stsz->total_entries = 0;
		stsz->table = (quicktime_stsz_table_t*)calloc(sizeof(quicktime_stsz_table_t), stsz->entries_allocated);
	}
}

void quicktime_stsz_init_timecode(quicktime_stsz_t *stsz)
  {
  stsz->sample_size = 4;

#if 0
  if(!stsz->entries_allocated)
    {
    stsz->entries_allocated = 2048;
		stsz->total_entries = 0;
		stsz->table = (quicktime_stsz_table_t*)calloc(sizeof(quicktime_stsz_table_t), stsz->entries_allocated);
    }
#endif
  }


void quicktime_stsz_init_audio(quicktime_t *file, 
	quicktime_stsz_t *stsz, 
	int channels, 
	int bits,
	char *compressor)
{
	/*stsz->sample_size = channels * bits / 8; */

	stsz->sample_size = 1;

	stsz->total_entries = 0;   /* set this when closing */
	stsz->entries_allocated = 0;
}

void quicktime_stsz_delete(quicktime_stsz_t *stsz)
{
	if(stsz->table) free(stsz->table);
}

void quicktime_stsz_dump(quicktime_stsz_t *stsz)
{
	int i;
	lqt_dump("     sample size (stsz)\n");
	lqt_dump("      version %d\n", stsz->version);
	lqt_dump("      flags %ld\n", stsz->flags);
	lqt_dump("      sample_size %lld\n", (long long)(stsz->sample_size));
	lqt_dump("      total_entries %ld\n", stsz->total_entries);
	
        if(!stsz->sample_size)
          {
          for(i = 0; i < stsz->total_entries; i++)
            {
            lqt_dump("       sample_size %llx (%lld)\n",
                     (long long)(stsz->table[i].size), (long long)(stsz->table[i].size));
            }
          }
}

void quicktime_read_stsz(quicktime_t *file, quicktime_stsz_t *stsz)
{
	int i;
	stsz->version = quicktime_read_char(file);
	stsz->flags = quicktime_read_int24(file);
	stsz->sample_size = quicktime_read_int32(file);
	stsz->total_entries = quicktime_read_int32(file);
	stsz->entries_allocated = stsz->total_entries;
        if(!stsz->sample_size)
          //        if(stsz->total_entries)
	{
        //        stsz->sample_size = 0;
		stsz->table = (quicktime_stsz_table_t*)calloc(sizeof(quicktime_stsz_table_t), stsz->entries_allocated);
		for(i = 0; i < stsz->total_entries; i++)
		{
			stsz->table[i].size = quicktime_read_int32(file);
		}
	}
}

void quicktime_write_stsz(quicktime_t *file, quicktime_stsz_t *stsz)
{
	int i;
	quicktime_atom_t atom;
	quicktime_atom_write_header(file, &atom, "stsz");

/* optimize if possible */
/* Xanim requires an unoptimized table for video. */
/* 	if(!stsz->sample_size) */
/* 	{ */
/* 		for(i = 0, result = 0; i < stsz->total_entries && !result; i++) */
/* 		{ */
/* 			if(stsz->table[i].size != stsz->table[0].size) result = 1; */
/* 		} */
/* 		 */
/* 		if(!result) */
/* 		{ */
/* 			stsz->sample_size = stsz->table[0].size; */
/* 			stsz->total_entries = 0; */
/* 			free(stsz->table); */
/* 		} */
/* 	} */

	quicktime_write_char(file, stsz->version);
	quicktime_write_int24(file, stsz->flags);

// Force idiosynchratic handling of fixed bitrate audio.
// Since audio has millions of samples it's not practical to declare a size
// of each sample.  Instead Quicktime stores a 1 for every sample's size and
// relies on the samples per chunk table to determine the chunk size.
	quicktime_write_int32(file, stsz->sample_size);
	quicktime_write_int32(file, stsz->total_entries);

	if(!stsz->sample_size)
	{
		for(i = 0; i < stsz->total_entries; i++)
		{
			quicktime_write_int32(file, stsz->table[i].size);
		}
	}

	quicktime_atom_write_footer(file, &atom);
}

void quicktime_update_stsz(quicktime_stsz_t *stsz, 
                           long sample, 
                           long sample_size)
  {
  if(!stsz->sample_size)
    {
    if(sample >= stsz->entries_allocated)
      {
      stsz->entries_allocated += 1024;
      stsz->table =
        (quicktime_stsz_table_t*)realloc(stsz->table,
                                         sizeof(quicktime_stsz_table_t) *
                                         stsz->entries_allocated);
      }
    stsz->table[sample].size = sample_size;
    if(sample >= stsz->total_entries) stsz->total_entries = sample + 1;
    }
  
  }