vc1: properly zero coded_block[] edges on new slice entry.

Previously, we would leave the left edge uninitialized, which led to
CBP prediction errors on slice edges, e.g. in SA10098.vc1.
(cherry picked from commit d4b9974465baf893e90527a366e7a7411ded1ef8)

Signed-off-by: Anton Khirnov <anton@khirnov.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c
index 8fca2da738..b17ce30b5c 100644
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@@ -3020,7 +3020,7 @@ static void vc1_decode_i_blocks_adv(VC1Context *v)
         s->mb_x = 0;
         ff_init_block_index(s);
         memset(&s->coded_block[s->block_index[0]-s->b8_stride], 0,
-               s->b8_stride * sizeof(*s->coded_block));
+               (1 + s->b8_stride) * sizeof(*s->coded_block));
     }
     for(; s->mb_y < s->end_mb_y; s->mb_y++) {
         s->mb_x = 0;