145 lines
3.1 KiB
ReStructuredText
Executable file
145 lines
3.1 KiB
ReStructuredText
Executable file
.. -*- coding: utf-8; mode: rst -*-
|
|
|
|
.. _V4L2-PIX-FMT-NV12M:
|
|
.. _v4l2-pix-fmt-nv12mt-16x16:
|
|
.. _V4L2-PIX-FMT-NV21M:
|
|
|
|
***********************************************************************************
|
|
V4L2_PIX_FMT_NV12M ('NM12'), V4L2_PIX_FMT_NV21M ('NM21'), V4L2_PIX_FMT_NV12MT_16X16
|
|
***********************************************************************************
|
|
|
|
|
|
V4L2_PIX_FMT_NV21M
|
|
V4L2_PIX_FMT_NV12MT_16X16
|
|
Variation of ``V4L2_PIX_FMT_NV12`` and ``V4L2_PIX_FMT_NV21`` with planes
|
|
non contiguous in memory.
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
This is a multi-planar, two-plane version of the YUV 4:2:0 format. The
|
|
three components are separated into two sub-images or planes.
|
|
``V4L2_PIX_FMT_NV12M`` differs from ``V4L2_PIX_FMT_NV12`` in that the
|
|
two planes are non-contiguous in memory, i.e. the chroma plane do not
|
|
necessarily immediately follows the luma plane. The luminance data
|
|
occupies the first plane. The Y plane has one byte per pixel. In the
|
|
second plane there is a chrominance data with alternating chroma
|
|
samples. The CbCr plane is the same width, in bytes, as the Y plane (and
|
|
of the image), but is half as tall in pixels. Each CbCr pair belongs to
|
|
four pixels. For example, Cb\ :sub:`0`/Cr\ :sub:`0` belongs to
|
|
Y'\ :sub:`00`, Y'\ :sub:`01`, Y'\ :sub:`10`, Y'\ :sub:`11`.
|
|
``V4L2_PIX_FMT_NV12MT_16X16`` is the tiled version of
|
|
``V4L2_PIX_FMT_NV12M`` with 16x16 macroblock tiles. Here pixels are
|
|
arranged in 16x16 2D tiles and tiles are arranged in linear order in
|
|
memory. ``V4L2_PIX_FMT_NV21M`` is the same as ``V4L2_PIX_FMT_NV12M``
|
|
except the Cb and Cr bytes are swapped, the CrCb plane starts with a Cr
|
|
byte.
|
|
|
|
``V4L2_PIX_FMT_NV12M`` is intended to be used only in drivers and
|
|
applications that support the multi-planar API, described in
|
|
:ref:`planar-apis`.
|
|
|
|
If the Y plane has pad bytes after each row, then the CbCr plane has as
|
|
many pad bytes after its rows.
|
|
|
|
**Byte Order.**
|
|
Each cell is one byte.
|
|
|
|
.. flat-table::
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
|
|
* - start0 + 0:
|
|
- Y'\ :sub:`00`
|
|
- Y'\ :sub:`01`
|
|
- Y'\ :sub:`02`
|
|
- Y'\ :sub:`03`
|
|
* - start0 + 4:
|
|
- Y'\ :sub:`10`
|
|
- Y'\ :sub:`11`
|
|
- Y'\ :sub:`12`
|
|
- Y'\ :sub:`13`
|
|
* - start0 + 8:
|
|
- Y'\ :sub:`20`
|
|
- Y'\ :sub:`21`
|
|
- Y'\ :sub:`22`
|
|
- Y'\ :sub:`23`
|
|
* - start0 + 12:
|
|
- Y'\ :sub:`30`
|
|
- Y'\ :sub:`31`
|
|
- Y'\ :sub:`32`
|
|
- Y'\ :sub:`33`
|
|
* -
|
|
* - start1 + 0:
|
|
- Cb\ :sub:`00`
|
|
- Cr\ :sub:`00`
|
|
- Cb\ :sub:`01`
|
|
- Cr\ :sub:`01`
|
|
* - start1 + 4:
|
|
- Cb\ :sub:`10`
|
|
- Cr\ :sub:`10`
|
|
- Cb\ :sub:`11`
|
|
- Cr\ :sub:`11`
|
|
|
|
|
|
**Color Sample Location:**
|
|
|
|
|
|
|
|
.. flat-table::
|
|
:header-rows: 0
|
|
:stub-columns: 0
|
|
|
|
* -
|
|
- 0
|
|
-
|
|
- 1
|
|
- 2
|
|
-
|
|
- 3
|
|
* - 0
|
|
- Y
|
|
-
|
|
- Y
|
|
- Y
|
|
-
|
|
- Y
|
|
* -
|
|
-
|
|
- C
|
|
-
|
|
-
|
|
- C
|
|
-
|
|
* - 1
|
|
- Y
|
|
-
|
|
- Y
|
|
- Y
|
|
-
|
|
- Y
|
|
* -
|
|
* - 2
|
|
- Y
|
|
-
|
|
- Y
|
|
- Y
|
|
-
|
|
- Y
|
|
* -
|
|
-
|
|
- C
|
|
-
|
|
-
|
|
-
|
|
- C
|
|
-
|
|
* - 3
|
|
- Y
|
|
-
|
|
- Y
|
|
- Y
|
|
-
|
|
- Y
|