130 lines
2.5 KiB
ReStructuredText
130 lines
2.5 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
|
|
|
|
.. _V4L2-PIX-FMT-NV12:
|
|
.. _V4L2-PIX-FMT-NV21:
|
|
|
|
******************************************************
|
|
V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')
|
|
******************************************************
|
|
|
|
|
|
V4L2_PIX_FMT_NV21
|
|
Formats with ½ horizontal and vertical chroma resolution, also known as
|
|
YUV 4:2:0. One luminance and one chrominance plane with alternating
|
|
chroma samples as opposed to ``V4L2_PIX_FMT_YVU420``
|
|
|
|
|
|
Description
|
|
===========
|
|
|
|
These are two-plane versions of the YUV 4:2:0 format. The three
|
|
components are separated into two sub-images or planes. The Y plane is
|
|
first. The Y plane has one byte per pixel. For ``V4L2_PIX_FMT_NV12``, a
|
|
combined CbCr plane immediately follows the Y plane in memory. 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_NV21`` is
|
|
the same except the Cb and Cr bytes are swapped, the CrCb plane starts
|
|
with a Cr byte.
|
|
|
|
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
|
|
|
|
* - start + 0:
|
|
- Y'\ :sub:`00`
|
|
- Y'\ :sub:`01`
|
|
- Y'\ :sub:`02`
|
|
- Y'\ :sub:`03`
|
|
* - start + 4:
|
|
- Y'\ :sub:`10`
|
|
- Y'\ :sub:`11`
|
|
- Y'\ :sub:`12`
|
|
- Y'\ :sub:`13`
|
|
* - start + 8:
|
|
- Y'\ :sub:`20`
|
|
- Y'\ :sub:`21`
|
|
- Y'\ :sub:`22`
|
|
- Y'\ :sub:`23`
|
|
* - start + 12:
|
|
- Y'\ :sub:`30`
|
|
- Y'\ :sub:`31`
|
|
- Y'\ :sub:`32`
|
|
- Y'\ :sub:`33`
|
|
* - start + 16:
|
|
- Cb\ :sub:`00`
|
|
- Cr\ :sub:`00`
|
|
- Cb\ :sub:`01`
|
|
- Cr\ :sub:`01`
|
|
* - start + 20:
|
|
- 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
|