Download-Tools/mkvtoolnix
1
0
Fork 0
mirror of https://gitlab.com/mbunkus/mkvtoolnix.git synced 2025-02-26 08:22:31 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fine-tuned the MPEG1/2 ES detection.

Browse Source
This commit is contained in:
Moritz Bunkus 2008-10-04 18:53:24 +00:00
parent 1e02fb1c9b
commit 0f86603685
2 changed files with 34 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/common/mpeg4_common.h
View File

@ -33,6 +33,8 @@
#define MPEGVIDEO_MPEG_PROGRAM_END_CODE 0x000001b9
#define MPEGVIDEO_EXT_START_CODE 0x000001b5
#define MPEGVIDEO_PICTURE_START_CODE 0x00000100
#define MPEGVIDEO_FIRST_SLICE_START_CODE 0x00000101
#define MPEGVIDEO_LAST_SLICE_START_CODE 0x000001af
/** Start code for a MPEG-4 part 2 visual object sequence start marker */
#define MPEGVIDEO_VOS_START_CODE 0x000001b0

43
src/input/r_mpeg_es.cpp
View File

@ -64,30 +64,51 @@ mpeg_es_reader_c::probe_file(mm_io_c *io,
if (!mpeg_is_start_code(value))
return 0;
bool sequence_start_code_found = false;
bool picture_start_code_found = false;
bool gop_start_code_found = false;
bool sequence_start_code_found = false;
bool ext_start_code_found = false;
bool picture_start_code_found = false;
bool slice_start_code_found = false;
bool ok = false;
// Let's look for a MPEG ES start code inside the first 1 MB.
int i;
for (i = 4; i < num_read - 1; i++) {
if (MPEGVIDEO_SEQUENCE_START_CODE == value)
sequence_start_code_found = true;
else if (MPEGVIDEO_PICTURE_START_CODE == value)
picture_start_code_found = true;
else if (MPEGVIDEO_GOP12_START_CODE == value)
gop_start_code_found = true;
if (mpeg_is_start_code(value)) {
mxverb(3, boost::format("mpeg_es_detection: start code found; fourth byte: 0x%|1$02x|\n") % (value & 0xff));
if (sequence_start_code_found && picture_start_code_found && gop_start_code_found)
break;
if (MPEGVIDEO_SEQUENCE_START_CODE == value)
sequence_start_code_found = true;
else if (MPEGVIDEO_PICTURE_START_CODE == value)
picture_start_code_found = true;
else if (MPEGVIDEO_GOP12_START_CODE == value)
gop_start_code_found = true;
else if (MPEGVIDEO_EXT_START_CODE == value)
gop_start_code_found = true;
else if ((MPEGVIDEO_FIRST_SLICE_START_CODE >= value) && (MPEGVIDEO_LAST_SLICE_START_CODE <= value))
slice_start_code_found = true;
ok = sequence_start_code_found && picture_start_code_found && (gop_start_code_found || ext_start_code_found || slice_start_code_found);
if (ok)
break;
}
value <<= 8;
value |= buf[i];
}
mxverb(3,
boost::format("mpeg_es_detection: sequence %1% picture %2% gop %3% ext %4% slice %5%\n")
% sequence_start_code_found % picture_start_code_found % gop_start_code_found % ext_start_code_found % slice_start_code_found);
safefree(buf);
if (!(sequence_start_code_found && picture_start_code_found && gop_start_code_found))
if (!ok)
return 0;
// Let's try to read one frame.