Michael Niedermayer 74fd2c3ddb 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 <pengbin@visionular.com>
Reviewed-by: Bin Peng <pengbin@visionular.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

2025-05-13 00:20:23 +02:00

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