54f38fcae5
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").
As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.
Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
151 lines
3.0 KiB
ReStructuredText
151 lines
3.0 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/userspace-api/media/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _V4L2-PIX-FMT-YVU420:
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.. _V4L2-PIX-FMT-YUV420:
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**********************************************************
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V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12')
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**********************************************************
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V4L2_PIX_FMT_YUV420
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Planar formats with ½ horizontal and vertical chroma resolution, also
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known as YUV 4:2:0
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Description
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===========
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These are planar formats, as opposed to a packed format. The three
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components are separated into three sub- images or planes. The Y plane
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is first. The Y plane has one byte per pixel. For
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``V4L2_PIX_FMT_YVU420``, the Cr plane immediately follows the Y plane in
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memory. The Cr plane is half the width and half the height of the Y
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plane (and of the image). Each Cr belongs to four pixels, a two-by-two
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square of the image. For example, Cr\ :sub:`0` belongs to Y'\ :sub:`00`,
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Y'\ :sub:`01`, Y'\ :sub:`10`, and Y'\ :sub:`11`. Following the Cr plane
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is the Cb plane, just like the Cr plane. ``V4L2_PIX_FMT_YUV420`` is the
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same except the Cb plane comes first, then the Cr plane.
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If the Y plane has pad bytes after each row, then the Cr and Cb planes
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have half as many pad bytes after their rows. In other words, two Cx
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rows (including padding) is exactly as long as one Y row (including
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padding).
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**Byte Order.**
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Each cell is one byte.
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.. flat-table::
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:header-rows: 0
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:stub-columns: 0
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* - start + 0:
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- Y'\ :sub:`00`
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- Y'\ :sub:`01`
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- Y'\ :sub:`02`
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- Y'\ :sub:`03`
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* - start + 4:
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- Y'\ :sub:`10`
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- Y'\ :sub:`11`
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- Y'\ :sub:`12`
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- Y'\ :sub:`13`
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* - start + 8:
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- Y'\ :sub:`20`
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- Y'\ :sub:`21`
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- Y'\ :sub:`22`
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- Y'\ :sub:`23`
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* - start + 12:
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- Y'\ :sub:`30`
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- Y'\ :sub:`31`
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- Y'\ :sub:`32`
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- Y'\ :sub:`33`
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* - start + 16:
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- Cr\ :sub:`00`
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- Cr\ :sub:`01`
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* - start + 18:
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- Cr\ :sub:`10`
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- Cr\ :sub:`11`
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* - start + 20:
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- Cb\ :sub:`00`
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- Cb\ :sub:`01`
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* - start + 22:
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- Cb\ :sub:`10`
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- Cb\ :sub:`11`
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**Color Sample Location:**
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.. flat-table::
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:header-rows: 0
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:stub-columns: 0
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* -
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- 0
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-
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- 1
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-
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- 2
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* - 0
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- Y
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- Y
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- Y
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-
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- Y
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* -
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- C
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- C
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* - 1
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- Y
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- Y
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- Y
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- Y
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- Y
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- Y
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* -
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- C
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* - 3
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- Y
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- Y
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- Y
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- Y
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