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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mpeg3private.inc"
void copy_data(FILE *out, FILE *in, long bytes)
{
long fragment_size = 0x100000;
char *buffer = malloc(fragment_size);
long i;
for(i = 0; i < bytes; i += fragment_size)
{
if(i + fragment_size > bytes) fragment_size = bytes - i;
if(!fread(buffer, 1, fragment_size, in))
{
perror("copy_data");
}
if(!fwrite(buffer, 1, fragment_size, out))
{
perror("copy_data");
}
}
free(buffer);
}
void split_video(char *path, long default_fragment_size)
{
long current_byte = 0;
int result = 0;
int i = 0;
long total_bytes;
FILE *in = fopen(path, "r");
char *sequence_hdr;
long sequence_hdr_size;
unsigned long header = 0;
long header_start;
long header_end;
if(!in)
{
perror("split_file");
return;
}
fseek(in, 0, SEEK_END);
total_bytes = ftell(in);
fseek(in, 0, SEEK_SET);
// Copy sequence header
do{
header <<= 8;
header = (header & 0xffffffff) | getc(in);
}while(header != MPEG3_SEQUENCE_START_CODE && !feof(in));
header_start = ftell(in) - 4;
do{
header <<= 8;
header = (header & 0xffffffff) | getc(in);
}while(header != MPEG3_GOP_START_CODE && !feof(in));
header_end = ftell(in) - 4;
sequence_hdr_size = header_end - header_start;
sequence_hdr = malloc(sequence_hdr_size);
fseek(in, header_start, SEEK_SET);
fread(sequence_hdr, 1, sequence_hdr_size, in);
fseek(in, 0, SEEK_SET);
while(current_byte < total_bytes && !result)
{
FILE *out;
char outpath[1024];
long fragment_size;
sprintf(outpath, "%s%02d", path, i);
out = fopen(outpath, "w");
if(!out)
{
perror("split_file");
break;
}
// Default fragment size
fragment_size = default_fragment_size;
// Corrected fragment size
if(current_byte + fragment_size >= total_bytes)
{
fragment_size = total_bytes - current_byte;
}
else
{
header = 0;
// Get GOP header
fseek(in, current_byte + fragment_size, SEEK_SET);
do
{
fseek(in, -1, SEEK_CUR);
header >>= 8;
header |= ((unsigned long)fgetc(in)) << 24;
fseek(in, -1, SEEK_CUR);
}while(ftell(in) > 0 && header != MPEG3_GOP_START_CODE);
fragment_size = ftell(in) - current_byte;
fseek(in, current_byte, SEEK_SET);
}
// Put sequence header
if(current_byte > 0)
{
fwrite(sequence_hdr, 1, sequence_hdr_size, out);
}
// Put data
copy_data(out, in, fragment_size);
fclose(out);
i++;
current_byte += fragment_size;
}
free(sequence_hdr);
}
int main(int argc, char *argv[])
{
long bytes = 0;
int i;
if(argc < 2)
{
fprintf(stderr, "Split elementary streams into chunks of bytes.\n"
"Usage: mpeg3split -b bytes <infile>\n");
exit(1);
}
for(i = 1; i < argc; i++)
{
if(!strcmp(argv[i], "-b"))
{
if(i < argc - 1)
{
i++;
bytes = atol(argv[i]);
}
else
{
fprintf(stderr, "-b must be paired with a value\n");
exit(1);
}
}
else
if(bytes > 0)
{
// Split a file
split_video(argv[i], bytes);
}
else
{
fprintf(stderr, "No value for bytes specified,\n");
exit(1);
}
}
}
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