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| author | Reinhard Nißl <rnissl@gmx.de> | 2007-04-11 22:47:14 +0200 |
|---|---|---|
| committer | Reinhard Nißl <rnissl@gmx.de> | 2007-04-11 22:47:14 +0200 |
| commit | 70340520422bd57265c125c9114bf0804a0fcfb6 (patch) | |
| tree | 5efba528e073e406fc9c88c31e4f14e8bbaa129f | |
| parent | c552e457732c3c7b84b66ed8548713be52561487 (diff) | |
| download | xine-lib-70340520422bd57265c125c9114bf0804a0fcfb6.tar.gz xine-lib-70340520422bd57265c125c9114bf0804a0fcfb6.tar.bz2 | |
Improve MPEG2 detection to have it ready for correct aspect ratio
determination.
The current code detects MPEG2 when parsing the sequence extention
which appears only in MPEG2 streams. But this is to late for correct
aspect ratio determination which happens earlier and therefore
assumes MPEG1. The result is a totally wrong aspect ratio.
To fix this issue, the next start code (which is already available
at that time) is passed to parse_chunk() too, which can then be
used to detect a MPEG2 extension start code early enough before
the aspect ratio is determined.
| -rw-r--r-- | src/libmpeg2/decode.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/src/libmpeg2/decode.c b/src/libmpeg2/decode.c index a2bb868df..3b19feda1 100644 --- a/src/libmpeg2/decode.c +++ b/src/libmpeg2/decode.c @@ -236,7 +236,7 @@ static void remember_metainfo (mpeg2dec_t *mpeg2dec) { } static inline int parse_chunk (mpeg2dec_t * mpeg2dec, int code, - uint8_t * buffer) + uint8_t * buffer, int next_code) { picture_t * picture; int is_frame_done; @@ -393,6 +393,11 @@ static inline int parse_chunk (mpeg2dec_t * mpeg2dec, int code, /* abort(); */ break; } + + /* according to ISO/IEC 13818-2, an extension start code will follow. + * Otherwise the stream follows ISO/IEC 11172-2 which means MPEG1 */ + picture->mpeg1 = (next_code != 0xb5); + if (mpeg2dec->force_aspect) picture->aspect_ratio_information = mpeg2dec->force_aspect; if (mpeg2dec->is_sequence_needed ) { @@ -638,7 +643,7 @@ int mpeg2_decode_data (mpeg2dec_t * mpeg2dec, uint8_t * current, uint8_t * end, current = copy_chunk (mpeg2dec, current, end); if (current == NULL) break; - ret += parse_chunk (mpeg2dec, code, mpeg2dec->chunk_buffer); + ret += parse_chunk (mpeg2dec, code, mpeg2dec->chunk_buffer, mpeg2dec->code); } libmpeg2_accel_frame_completion(&mpeg2dec->accel, mpeg2dec->frame_format, @@ -805,7 +810,7 @@ void mpeg2_close (mpeg2dec_t * mpeg2dec) void mpeg2_find_sequence_header (mpeg2dec_t * mpeg2dec, uint8_t * current, uint8_t * end){ - uint8_t code; + uint8_t code, next_code; picture_t *picture = mpeg2dec->picture; mpeg2dec->seek_mode = 1; @@ -815,6 +820,7 @@ void mpeg2_find_sequence_header (mpeg2dec_t * mpeg2dec, current = copy_chunk (mpeg2dec, current, end); if (current == NULL) return ; + next_code = mpeg2dec->code; /* printf ("looking for sequence header... %02x\n", code); */ @@ -825,6 +831,11 @@ void mpeg2_find_sequence_header (mpeg2dec_t * mpeg2dec, printf ("libmpeg2: bad sequence header\n"); continue; } + + /* according to ISO/IEC 13818-2, an extension start code will follow. + * Otherwise the stream follows ISO/IEC 11172-2 which means MPEG1 */ + picture->mpeg1 = (next_code != 0xb5); + if (mpeg2dec->force_aspect) picture->aspect_ratio_information = mpeg2dec->force_aspect; if (mpeg2dec->is_sequence_needed) { |