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added mpeg ts support

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This commit is contained in:
Mathias Panzenböck 2013-01-29 00:45:20 +01:00
parent 41d9aaf905
commit f6db42aa32
4 changed files with 266 additions and 5 deletions
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6
README.md
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@ -122,6 +122,7 @@ files.
mpg123 MPEG layer 1/2/3 files (MP1, MP2, MP3)
mpeg1 MPEG 1 System Streams
mpegps MPEG 2 Program Streams
mpegts MPEG 2 Transport Streams
mp4 MP4 files (M4A, M4V, 3GPP etc.)
ogg Ogg files (Vorbis, Opus, Theora, etc.)
png Portable Network Graphics files
@ -136,8 +137,9 @@ files.
MP3 files usually have an ID3v2 tag at the start, so using the
'id3v2' format is the better option anyway.
The detection accuracy of MOD files is not much better and thus
the 'mpg123' and 'mod' formats are per default disabled.
The detection accuracy of MOD files is not much better and of MPEG TS
it is even worse and thus the 'mpg123', 'mpegts' and 'mod' formats
are per default disabled.
NOTE: When using only the 'mpg123' format but not 'id3v2' any ID3v2
tag will be stripped. ID3v1 tags will still be kept.

15
src/mediaextract.c
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@ -155,6 +155,7 @@ static int usage(int argc, char **argv)
" mpg123 MPEG layer 1/2/3 files (MP1, MP2, MP3)\n"
" mpeg1 MPEG 1 System Streams\n"
" mpegps MPEG 2 Program Streams\n"
" mpegts MPEG 2 Transport Streams\n"
" mp4 MP4 files (M4A, M4V, 3GPP etc.)\n"
" ogg Ogg files (Vorbis, Opus, Theora, etc.)\n"
" png Portable Network Graphics files\n"
@ -169,8 +170,9 @@ static int usage(int argc, char **argv)
" MP3 files usually have an ID3v2 tag at the start, so using the\n"
" 'id3v2' format is the better option anyway.\n"
"\n"
" The detection accuracy of MOD files is not much better and thus\n"
" the 'mpg123' and 'mod' formats are per default disabled.\n"
" The detection accuracy of MOD files is not much better and of MPEG TS\n"
" it is even worse and thus the 'mpg123', 'mpegts' and 'mod' formats\n"
" are per default disabled.\n"
"\n"
" NOTE: When using only the 'mpg123' format but not 'id3v2' any ID3v2\n"
" tag will be stripped. ID3v1 tags will still be kept.\n"
@ -442,7 +444,14 @@ int do_extract(const uint8_t *filedata, size_t filesize, const struct extract_op
continue;
}
if (formats & (MPEG1 | MPEGPS | MPEGVS | MPEGTS) && IS_MPEG_MAGIC(magic) && mpeg_isfile(ptr, input_len, formats, &length))
if (formats & (MPEG1 | MPEGPS | MPEGVS) && IS_MPEG_MAGIC(magic) && mpeg_isfile(ptr, input_len, formats, &length))
{
WRITE_FILE(ptr, length, "mpg");
ptr += length;
continue;
}
if (formats & MPEGTS && IS_MPEG_TS_MAGIC(ptr) && mpeg_isfile(ptr, input_len, formats, &length))
{
WRITE_FILE(ptr, length, "mpg");
ptr += length;

224
src/mpeg.c Normal file
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@ -0,0 +1,224 @@
#include "mpeg.h"
// See: http://www.andrewduncan.ws/MPEG/MPEG-2_Picts.html
// http://lostcode.wikidot.com/transportstream
// http://en.wikipedia.org/wiki/MPEG_transport_stream
// http://dmr.ath.cx/notes/mpeg1.html
static size_t mpeg_ispacket(const uint8_t *data, size_t input_len)
{
if (input_len < 6)
return 0;
uint32_t magic = MAGIC(data);
if (magic < MPEG_PKG_MIN_MAGIC || magic > MPEG_PKG_MAX_MAGIC)
return 0;
size_t length = 6 + ((data[4] << 8) | data[5]);
if (length <= 6 || length > input_len)
return 0;
// truncated file?
if (length > input_len)
return input_len;
return length;
}
static size_t mpeg_ispack(const uint8_t *data, size_t input_len, enum fileformat *format)
{
if (input_len < 12 || MAGIC(data) != MPEG_MAGIC)
return 0;
size_t length = 12;
switch (data[4] >> 6)
{
case 0: // MPEG 1
*format = MPEG1;
break;
case 1: // MPEG 2
if (input_len < 14)
return 0;
// stuffing
length = 14 + (data[13] & 0x3);
if (length > input_len)
return 0;
if (!(data[4] & 0x4) || !(data[ 6] & 0x4) || !(data[8] & 0x4) ||
!(data[9] & 0x1) || !(data[12] & 0x3))
return 0;
*format = MPEGPS;
break;
default:
return 0;
}
const uint8_t *ptr = data + length;
const uint8_t *end = data + input_len - 6;
while (ptr < end)
{
size_t pkglen = mpeg_ispacket(ptr, input_len - length);
if (pkglen == 0)
break;
length += pkglen;
ptr += pkglen;
}
return length;
}
static size_t mpeg_ispacks(const uint8_t *data, size_t input_len, int formats)
{
enum fileformat format = NONE;
size_t length = mpeg_ispack(data, input_len, &format);
if (length == 0 || (format & formats) == 0)
return 0;
while (length < input_len)
{
// ignore up to 64 nil bytes
size_t maxskip = input_len - length;
if (maxskip > 66) maxskip = length + 66;
else maxskip += length;
size_t i = length;
while (i < maxskip && data[i] == 0)
++ i;
// there are 2 nil bytes at the start of the magic
if ((i - length) < 2)
break;
length = i - 2;
enum fileformat nextformat = NONE;
size_t nextlen = mpeg_ispack(data + length, input_len - length, &nextformat);
if (nextlen == 0 || nextformat != format)
break;
length += nextlen;
}
if (length <= input_len - 4 && MAGIC(data + length) == MPEG_END_MAGIC)
length += 4;
return length;
}
#if 0
// TODO: find out how to determine the sizes of all the parts of a MPEG VS
static size_t mpeg_isvshdr(const uint8_t *data, size_t input_len)
{
if (input_len < 12 || MAGIC(data) != MPEG_VS_HDR_MAGIC)
return 0;
size_t width = (data[4] << 4) | (data[5] >> 4);
size_t height = (data[5] << 4) | data[6];
size_t bitrate = (data[8] << 10) | (data[9] << 2) | (data[10] >> 6);
if (!width || !height || !bitrate || !(data[10] & 0x20))
return 0;
if (data[11] & 0x2)
{
if (input_len < 76)
return 0;
if (data[75] & 0x1)
{
if (input_len < 140)
return 0;
return 140;
}
return 76;
}
return 12;
}
static size_t mpeg_isvs(const uint8_t *data, size_t input_len)
{
size_t length = mpeg_isvshdr(data, input_length);
if (!length)
return 0;
// TODO
return length;
}
#endif
static size_t mpeg_istspack(const uint8_t *data, size_t input_len)
{
// There are versions with 192 and 208 bytes that prepend/append
// a 4 byte timecode or 20 byte for error correction. Because
// I don't have any example files and don't know how to detect
// these variations I haven't implemented them for now. See:
// http://lostcode.wikidot.com/transportstream
if (input_len < 188 || data[0] != MPEG_TS_SYNC_BYTE || !(data[3] & 0x30))
return 0;
if (data[3] & 0x20)
{
size_t hdrlen = data[4];
if (hdrlen == 0 || hdrlen > 183)
return 0;
}
return 188;
}
static size_t mpeg_ists(const uint8_t *data, size_t input_len)
{
size_t length = 0;
while (length < input_len)
{
size_t pkglen = mpeg_istspack(data + length, input_len - length);
if (!pkglen)
break;
length += pkglen;
}
return length;
}
int mpeg_isfile(const uint8_t *data, size_t input_len, int formats, size_t *lengthptr)
{
size_t length = 0;
if (formats & (MPEG1 | MPEGPS))
length = mpeg_ispacks(data, input_len, formats);
// if (!length && formats & MPEGVS)
// length = mpeg_isvs(data, input_len);
if (!length && formats & MPEGTS)
length = mpeg_ists(data, input_len);
if (length)
{
if (lengthptr)
*lengthptr = length;
return 1;
}
return 0;
}

26
src/mpeg.h Normal file
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@ -0,0 +1,26 @@
#ifndef MEDIAEXTRACT_MPEG2_H__
#define MEDIAEXTRACT_MPEG2_H__
#include "mediaextract.h"
#define MPEG_MAGIC MAGIC("\0\0\x01\xBA")
#define MPEG_SYSHDR_MAGIC MAGIC("\0\0\x01\xBB")
#define MPEG_PKG_MIN_MAGIC MAGIC("\x00\x00\x01\xBB")
#define MPEG_PKG_MAX_MAGIC MAGIC("\x00\x00\x01\xFF")
#define MPEG_END_MAGIC MAGIC("\0\0\x01\xB9")
#define MPEG_VS_HDR_MAGIC MAGIC("\0\0\x01\xB3")
#define MPEG_VS_EXT_MAGIC MAGIC("\0\0\x01\xB5")
#define MPEG_VS_GRP_MAGIC MAGIC("\0\0\x01\xB8")
#define MPEG_VS_PCT_MAGIC MAGIC("\0\0\x01\x00")
#define MPEG_VS_END_MAGIC MAGIC("\0\0\x01\xB7")
#define MPEG_VS_MAGIC MPEG_VS_HDR_MAGIC
#define MPEG_TS_SYNC_BYTE 0x47
#define IS_MPEG_MAGIC(magic) ((magic) == MPEG_MAGIC)
#define IS_MPEG_TS_MAGIC(ptr) ((ptr)[0] == MPEG_TS_SYNC_BYTE && (ptr)[3] & 0x30)
int mpeg_isfile(const uint8_t *data, size_t input_len, int formats, size_t *lengthptr);
#endif /* MEDIAEXTRACT_MPEG2_H__ */