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| author | Michael Niedermayer <michaelni@gmx.at> | 2014-01-26 02:53:17 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2014-01-26 02:57:40 +0100 |
| commit | 7667afffb8dd54595ef2a959c385babd4c9c94cf (patch) | |
| tree | 9e8e1aac81980d15eff6670f92863533d6ed32a5 | |
| parent | 6a92598e149bcc2b5ec0a6c0cd940ef19b9ae86f (diff) | |
| download | ffmpeg-7667afffb8dd54595ef2a959c385babd4c9c94cf.tar.gz | |
avcodec/mpeg12dec: Revert Change to mpeg2_fast_decode_block_non_intra
This fixes the speed regression from 20626f53e9f41cb3db82329ed3db7d773cfa3a8f
and still checks sufficiently to prevent out of allocated memory accesses
due to the index
Before:
1823 decicycles in mpeg2_fast_decode_block_non_intra, 8388493 runs, 115 skips
After:
1808 decicycles in mpeg2_fast_decode_block_non_intra, 8388494 runs, 114 skips
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
| -rw-r--r-- | libavcodec/mpeg12dec.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c index f1899e0f9f..79fc65c03f 100644 --- a/libavcodec/mpeg12dec.c +++ b/libavcodec/mpeg12dec.c @@ -474,7 +474,6 @@ static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s, if (level != 0) { i += run; - check_scantable_index(s, i); j = scantable[i]; level = ((level * 2 + 1) * qscale) >> 1; level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1); @@ -486,7 +485,6 @@ static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s, level = SHOW_SBITS(re, &s->gb, 12); SKIP_BITS(re, &s->gb, 12); i += run; - check_scantable_index(s, i); j = scantable[i]; if (level < 0) { level = ((-level * 2 + 1) * qscale) >> 1; @@ -497,7 +495,7 @@ static inline int mpeg2_fast_decode_block_non_intra(MpegEncContext *s, } block[j] = level; - if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF) + if (((int32_t)GET_CACHE(re, &s->gb)) <= (int32_t)0xBFFFFFFF || i > 63) break; UPDATE_CACHE(re, &s->gb); |