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h264: Move slice_table clean out of frame_start

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Fixes inconsistency ultimately leading to an out of array read

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 746016598d)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer
2013-03-30 16:04:07 +01:00
parent b9058f58bd
commit 3f2efac0fe
1 changed files with 9 additions and 5 deletions
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14
libavcodec/h264.c
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@@ -1782,11 +1782,6 @@ int ff_h264_frame_start(H264Context *h)
h->block_offset[48 + 32 + i] = (4 * ((scan8[i] - scan8[0]) & 7) << pixel_shift) + 8 * h->uvlinesize * ((scan8[i] - scan8[0]) >> 3);
}
/* Some macroblocks can be accessed before they're available in case
* of lost slices, MBAFF or threading. */
memset(h->slice_table, -1,
(h->mb_height * h->mb_stride - 1) * sizeof(*h->slice_table));
// s->decode = (h->flags & CODEC_FLAG_PSNR) || !s->encoding ||
// h->cur_pic.f.reference /* || h->contains_intra */ || 1;
@@ -3499,6 +3494,15 @@ static int decode_slice_header(H264Context *h, H264Context *h0)
} else {
release_unused_pictures(h, 0);
}
/* Some macroblocks can be accessed before they're available in case
* of lost slices, MBAFF or threading. */
if (FIELD_PICTURE) {
for(i = (h->picture_structure == PICT_BOTTOM_FIELD); i<h->mb_height; i++)
memset(h->slice_table + i*h->mb_stride, -1, (h->mb_stride - (i+1==h->mb_height)) * sizeof(*h->slice_table));
} else {
memset(h->slice_table, -1,
(h->mb_height * h->mb_stride - 1) * sizeof(*h->slice_table));
}
}
if (h != h0 && (ret = clone_slice(h, h0)) < 0)
return ret;