[FFmpeg-devel] [PATCH] Fix VP8 aliasing problems.
Luca Barbato
lu_zero
Fri Jan 28 16:06:51 CET 2011
On 01/28/2011 03:51 PM, Ronald S. Bultje wrote:
> Replace * (uint32_t *) buf accesses with AV_WN32A/AV_COPY32.
> ---
> libavcodec/vp8.c | 12 ++++++------
> 1 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
> index 3691f15..66a7c4d 100644
> --- a/libavcodec/vp8.c
> +++ b/libavcodec/vp8.c
> @@ -1132,9 +1132,9 @@ void intra_predict(VP8Context *s, uint8_t *dst[3], VP8Macroblock *mb,
> linesize = 8;
> if (!(mb_y + y)) {
> copy_dst[3] = 127U;
> - * (uint32_t *) (copy_dst + 4) = 127U * 0x01010101U;
> + AV_WN32A(copy_dst+4, 127U * 0x01010101U);
> } else {
> - * (uint32_t *) (copy_dst + 4) = * (uint32_t *) (ptr+4*x-s->linesize);
> + AV_COPY32(copy_dst+4, ptr+4*x-s->linesize);
> if (!(mb_x + x)) {
> copy_dst[3] = 129U;
> } else {
> @@ -1158,10 +1158,10 @@ void intra_predict(VP8Context *s, uint8_t *dst[3], VP8Macroblock *mb,
> }
> s->hpc.pred4x4[mode](dst, topright, linesize);
> if (copy) {
> - * (uint32_t *) (ptr+4*x) = * (uint32_t *) (copy_dst + 12);
> - * (uint32_t *) (ptr+4*x+s->linesize) = * (uint32_t *) (copy_dst + 20);
> - * (uint32_t *) (ptr+4*x+s->linesize*2) = * (uint32_t *) (copy_dst + 28);
> - * (uint32_t *) (ptr+4*x+s->linesize*3) = * (uint32_t *) (copy_dst + 36);
> + AV_COPY32(ptr+4*x , copy_dst+12);
> + AV_COPY32(ptr+4*x+s->linesize , copy_dst+20);
> + AV_COPY32(ptr+4*x+s->linesize*2, copy_dst+28);
> + AV_COPY32(ptr+4*x+s->linesize*3, copy_dst+36);
> }
>
> nnz = s->non_zero_count_cache[y][x];
Looks fine.
--
Luca Barbato
Gentoo/linux
http://dev.gentoo.org/~lu_zero
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