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1b3bb57456
Luma and chroma qtables need to be written into two 16-register blocks, each table consisting of 64 bytes total. The blocks are contiguous and start at offset 0 for luma and at offset 0x40 for chroma. The seemingly innocent optimization of writing the two blocks using one loop causes side effects which result in improper values of quantization tables being used by the hardware during encoding. Visually this results in macroblocking artifacts around contrasting edges in encoded images. The artifacts look like horizontally flipped shadows of the said edges. Changing the write operations to non-relaxed variant doesn't help. This patch removes this premature optimization and after this change the macroblocking artifacts around contrasting edges are gone. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com> Tested-by: Ezequiel Garcia <ezequiel@collabora.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.