From 9c634d6d137fa2024579b2c23fa3f19053e7a910 Mon Sep 17 00:00:00 2001 From: Nicolas Dufresne Date: Mon, 21 Feb 2022 14:12:01 -0500 Subject: 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 Reviewed-by: Ezequiel Garcia Signed-off-by: Hans Verkuil --- Documentation/userspace-api/media/v4l/pixfmt-reserved.rst | 15 ++++----------- .../userspace-api/media/v4l/pixfmt-yuv-planar.rst | 6 ++++++ 2 files changed, 10 insertions(+), 11 deletions(-) (limited to 'Documentation/userspace-api') 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 -- cgit v1.2.3 From 88c63ac741266bf3fc0812578199dfb16a3c31b5 Mon Sep 17 00:00:00 2001 From: Nicolas Dufresne Date: Mon, 21 Feb 2022 14:37:27 -0500 Subject: doc: media: Document VP9 reference_mode miss-placement The reference_mode derived syntax is part of the compressed headers and should have been moved into the corresponding control structure. Document this mistake. The value can be set to 0 if the driver does not require compressed headers information. Signed-off-by: Nicolas Dufresne Reviewed-by: Andrzej Pietrasiewicz Signed-off-by: Hans Verkuil [hverkuil: fix small typo in comment] --- .../userspace-api/media/v4l/ext-ctrls-codec-stateless.rst | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'Documentation/userspace-api') diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst index cc080c4257d0..c6ef05e0d3a4 100644 --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst @@ -1692,7 +1692,12 @@ See section '7.3.1 Tx mode semantics' of the :ref:`vp9` specification for more d * - __u8 - ``reference_mode`` - Specifies the type of inter prediction to be used. See - :ref:`Reference Mode` for more details. + :ref:`Reference Mode` for more details. Note that + this is derived as part of the compressed header parsing process and + for this reason should have been part of + :c:type: `v4l2_ctrl_vp9_compressed_hdr` optional control. It is safe to + set this value to zero if the driver does not require compressed + headers. * - __u8 - ``reserved[7]`` - Applications and drivers must set this to zero. -- cgit v1.2.3