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| author | Nicolas Dufresne <nicolas.dufresne@collabora.com> | 2022-02-21 22:12:01 +0300 |
|---|---|---|
| committer | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2022-02-23 10:53:08 +0300 |
| commit | 9c634d6d137fa2024579b2c23fa3f19053e7a910 (patch) | |
| tree | c7c78f8a510ad0e11c6d808a11e7ad54c91c52d8 /Documentation/userspace-api | |
| parent | 884c8bd91828d851ede5489cb5b4134ffc61f965 (diff) | |
| download | linux-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.rst | 15 | ||||
| -rw-r--r-- | Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 6 |
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 |