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/*
This file is part of libextractor.
Copyright (C) 2004, 2005, 2006, 2009, 2012 Vidyut Samanta and Christian Grothoff
libextractor is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
libextractor 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with libextractor; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file plugins/mpeg_extractor.c
* @brief plugin to support MPEG files
* @author Christian Grothoff
*/
#include "platform.h"
#include "extractor.h"
#include <mpeg2dec/mpeg2.h>
/**
* Give meta data to extractor.
*
* @param t type of the meta data
* @param s meta data value in utf8 format
*/
#define ADD(s,t) do { if (0 != ec->proc (ec->cls, "mpeg", t, EXTRACTOR_METAFORMAT_UTF8, "text/plain", s, strlen (s) + 1)) goto EXIT; } while (0)
/**
* Main entry method for the 'video/mpeg' extraction plugin.
*
* @param ec extraction context provided to the plugin
*/
void
EXTRACTOR_mpeg_extract_method (struct EXTRACTOR_ExtractContext *ec)
{
mpeg2dec_t *handle;
const mpeg2_info_t *info;
void *buf;
ssize_t avail;
mpeg2_state_t state;
char format[256];
char lformat[256];
char gop_format[256];
int have_gop;
uint64_t fsize;
unsigned int fail_count;
int did_seek;
int fmt1;
int fmt2;
int mime;
int fpal;
int fntsc;
int fsecam;
int fmac;
if (NULL == (handle = mpeg2_init ()))
return;
if (NULL == (info = mpeg2_info (handle)))
{
mpeg2_close (handle);
return;
}
fsize = ec->get_size (ec->cls);
buf = NULL;
have_gop = 0;
fail_count = 0;
did_seek = 0;
fmt1 = 0;
fmt2 = 0;
mime = 0;
fpal = 0;
fntsc = 0;
fsecam = 0;
fmac = 0;
lformat[0] = '\0';
while (1)
{
state = mpeg2_parse (handle);
switch (state)
{
case STATE_BUFFER:
if (fail_count > 16)
goto EXIT; /* do not read large non-mpeg files */
fail_count++;
if (0 >= (avail = ec->read (ec->cls,
&buf,
16 * 1024)))
goto EXIT;
mpeg2_buffer (handle, buf, buf + avail);
break;
case STATE_SEQUENCE:
fail_count = 0;
format[0] = fsize;
format[0]++;
if (0 == mime)
{
mime = 1;
ADD ("video/mpeg", EXTRACTOR_METATYPE_MIMETYPE);
}
snprintf (format,
sizeof(format), "%ux%u",
info->sequence->width, info->sequence->height);
if (0 != strcmp (lformat,
format))
{
strcpy (lformat,
format);
ADD (format, EXTRACTOR_METATYPE_IMAGE_DIMENSIONS);
}
switch (info->sequence->flags & SEQ_VIDEO_FORMAT_UNSPECIFIED)
{
case SEQ_VIDEO_FORMAT_PAL:
if (0 == fpal)
{
fpal = 1;
ADD ("PAL", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
}
break;
case SEQ_VIDEO_FORMAT_NTSC:
if (0 == fntsc)
{
fntsc = 1;
ADD ("NTSC", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
}
break;
case SEQ_VIDEO_FORMAT_SECAM:
if (0 == fsecam)
{
fsecam = 1;
ADD ("SECAM", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
}
break;
case SEQ_VIDEO_FORMAT_MAC:
if (0 == fmac)
{
fmac = 1;
ADD ("MAC", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
}
break;
default:
break;
}
if ((info->sequence->flags & SEQ_FLAG_MPEG2) > 0)
{
if (0 == fmt1)
{
fmt1 = 1;
ADD ("MPEG2", EXTRACTOR_METATYPE_FORMAT_VERSION);
}
}
else
{
if (0 == fmt2)
{
fmt2 = 1;
ADD ("MPEG1", EXTRACTOR_METATYPE_FORMAT_VERSION);
}
}
if ( (0 == did_seek) &&
(fsize != -1) &&
(fsize > 1024 * 256 * 2) )
{
/* skip to the end of the mpeg for speed */
did_seek = 1;
ec->seek (ec->cls,
fsize - 256 * 1024,
SEEK_SET);
}
break;
case STATE_GOP:
fail_count = 0;
if ( (NULL != info->gop) &&
(0 != info->gop->pictures) )
{
snprintf (gop_format,
sizeof (gop_format),
"%02u:%02u:%02u (%u frames)",
info->gop->hours,
info->gop->minutes,
info->gop->seconds,
info->gop->pictures);
have_gop = 1;
}
break;
case STATE_SLICE:
fail_count = 0;
break;
case STATE_END:
fail_count = 0;
break;
case STATE_INVALID:
goto EXIT;
default:
break;
}
}
EXIT:
if (1 == have_gop)
ADD (gop_format, EXTRACTOR_METATYPE_DURATION);
mpeg2_close (handle);
}
/* end of mpeg_extractor.c */
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