summaryrefslogtreecommitdiff
path: root/Documentation/userspace-api/media/v4l/pixfmt-nv12.rst
blob: 19d47b38e02a54515ff113213a18d511631435ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
.. Permission is granted to copy, distribute and/or modify this
.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections

.. _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