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authorNicolas Dufresne <nicolas.dufresne@collabora.com>2022-02-21 22:12:01 +0300
committerHans Verkuil <hverkuil-cisco@xs4all.nl>2022-02-23 10:53:08 +0300
commit9c634d6d137fa2024579b2c23fa3f19053e7a910 (patch)
treec7c78f8a510ad0e11c6d808a11e7ad54c91c52d8 /Documentation/userspace-api
parent884c8bd91828d851ede5489cb5b4134ffc61f965 (diff)
downloadlinux-9c634d6d137fa2024579b2c23fa3f19053e7a910.tar.xz
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: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Diffstat (limited to 'Documentation/userspace-api')
-rw-r--r--Documentation/userspace-api/media/v4l/pixfmt-reserved.rst15
-rw-r--r--Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst6
2 files changed, 10 insertions, 11 deletions
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
index 2f2133b4cd9c..cabfa34b7db5 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
@@ -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
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
index 3a09d93d405b..570791fbc5c8 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
@@ -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