ffmpeg | branch: release/4.4 | Michael Niedermayer <mich...@niedermayer.cc> | Wed Apr 16 02:25:00 2025 +0200| [eb74fe6908eda63a848f3849d4936ae0d902dad0] | committer: Michael Niedermayer
avcodec/h264_mb: Fix tmp_cr for arm When decoding a bitstream with weighted-bipred enabled, the results on ARM and x86 platforms may differ. The reason for the inconsistency is that the value of STRIDE_ALIGN differs between platforms. And STRIDE_ALIGN is set to the buffer stride of temporary buffers for U and V components in mc_part_weighted. If the buffer stride is 32 or 64 (as on x86 platforms), the U and V pixels can be interleaved row by row without overlapping, resulting in correct output. However, on ARM platforms where the stride is 16, the V component did overwrite part of the U component's pixels, leading to incorrect predicted pixels. The bug can be reproduced by the following bitstream. https://trac.ffmpeg.org/attachment/ticket/11357/inter_weighted_bipred2.264 Fixes: ticket 11357 Commit-msg-mostly-by: Bin Peng <peng...@visionular.com> Reviewed-by: Bin Peng <peng...@visionular.com> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> (cherry picked from commit 74fd2c3ddbaf1fef5c4777784aa72b5747ad389c) Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=eb74fe6908eda63a848f3849d4936ae0d902dad0 --- libavcodec/h264_mb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/h264_mb.c b/libavcodec/h264_mb.c index 3cd17b7e4b..226c0ff09a 100644 --- a/libavcodec/h264_mb.c +++ b/libavcodec/h264_mb.c @@ -406,7 +406,7 @@ static av_always_inline void mc_part_weighted(const H264Context *h, H264SliceCon /* don't optimize for luma-only case, since B-frames usually * use implicit weights => chroma too. */ uint8_t *tmp_cb = sl->bipred_scratchpad; - uint8_t *tmp_cr = sl->bipred_scratchpad + (16 << pixel_shift); + uint8_t *tmp_cr = sl->bipred_scratchpad + (8 << pixel_shift + (chroma_idc == 3)); uint8_t *tmp_y = sl->bipred_scratchpad + 16 * sl->mb_uvlinesize; int refn0 = sl->ref_cache[0][scan8[n]]; int refn1 = sl->ref_cache[1][scan8[n]]; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
