Commit 9c634d6d authored by Nicolas Dufresne's avatar Nicolas Dufresne Committed by Hans Verkuil
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doc: media: Document MM21 tiled format 

MM21 has been documented through two software implementation [0] in libyuv
and [2] GStreamer. This format is similar to other tiled format, though it
uses uneven tile sizes. The luma tiles are 16x32 while the chroma tile have
a subsampled size of 16x16. This is the uncompressed cousin of
V4L2_PIX_FMT_MT21C and shares its tiling pattern and alignment.

[0] https://chromium.googlesource.com/libyuv/libyuv/+/b4ddbaf549a1bf5572bf703fd2862d1eb7380c6a
[1] https://gitlab.freedesktop.org/gstreamer/gstreamer/-/commit/c9b127dae3af4b3fe78468e697cb491902425254



Signed-off-by: default avatarNicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: default avatarEzequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
parent 884c8bd9

Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

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@@ -233,19 +233,12 @@ please make a proposal on the linux-media mailing list. 


      - ``V4L2_PIX_FMT_MT21C``

      - 'MT21'

      - Compressed two-planar YVU420 format used by Mediatek MT8173.

	The compression is lossless.

	It is an opaque intermediate format and the MDP hardware must be

      - Compressed two-planar YVU420 format used by Mediatek MT8173, MT8192,

        MT8195 and more. The compression is lossless. This format have

	similitude with ``V4L2_PIX_FMT_MM21`` in term of alignment and tiling.

	It remains an opaque intermediate format and the MDP hardware must be

	used to convert ``V4L2_PIX_FMT_MT21C`` to ``V4L2_PIX_FMT_NV12M``,

	``V4L2_PIX_FMT_YUV420M`` or ``V4L2_PIX_FMT_YVU420``.

    * .. _V4L2-PIX-FMT-MM21:



      - ``V4L2_PIX_FMT_MM21``

      - 'MM21'

      - Non-compressed, tiled two-planar format used by Mediatek MT8183.

	This is an opaque intermediate format and the MDP3 hardware can be

	used to convert it to other formats.



.. raw:: latex



    \normalsize

Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst

+6 −0
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@@ -296,6 +296,12 @@ tiles linearly in memory. The line stride and image height must be 
aligned to a multiple of 32. The layouts of the luma and chroma planes are

identical.



``V4L2_PIX_FMT_MM21`` store luma pixel in 16x32 tiles, and chroma pixels

in 16x16 tiles. The line stride must be aligned to a multiple of 16 and the

image height must be aligned to a multiple of 32. The number of luma and chroma

tiles are identical, even though the tile size differ. The image is formed of

two non-contiguous planes.



.. _nv12mt:



.. kernel-figure:: nv12mt.svg