swscale: fix crash with dithering due incorrect offset calculation.

ptrdiff_t can be 4 bytes, which leads to the next element being 4-byte
aligned and thus at a different offset than intended. Forcing 8-byte
alignment forces equal offset of dither16/32 on x86-32 and x86-64.

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
pull/2/head
Anton Mitrofanov 14 years ago committed by Ronald S. Bultje
parent fdb94444be
commit 142e76f105
  1. 7
      libswscale/swscale_internal.h

@ -345,10 +345,13 @@ typedef struct SwsContext {
DECLARE_ALIGNED(8, uint64_t, v_temp);
DECLARE_ALIGNED(8, uint64_t, y_temp);
int32_t alpMmxFilter[4*MAX_FILTER_SIZE];
// alignment of these values is not necessary, but merely here
// to maintain the same offset across x8632 and x86-64. Once we
// use proper offset macros in the asm, they can be removed.
DECLARE_ALIGNED(8, ptrdiff_t, uv_off_px); ///< offset (in pixels) between u and v planes
DECLARE_ALIGNED(8, ptrdiff_t, uv_off_byte); ///< offset (in bytes) between u and v planes
uint16_t dither16[8];
uint32_t dither32[8];
DECLARE_ALIGNED(8, uint16_t, dither16)[8];
DECLARE_ALIGNED(8, uint32_t, dither32)[8];
const uint8_t *chrDither8, *lumDither8;

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