Documentation/linux_tv/media/v4l/pixfmt-nv12.rst

.. -*- coding: utf-8; mode: rst -*-

.. _V4L2-PIX-FMT-NV12:

******************************************************
V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')
******************************************************

*man V4L2_PIX_FMT_NV12(2)*

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
    :widths:       2 1 1 1 1


    -  .. row 1

       -  start + 0:

       -  Y'\ :sub:`00`

       -  Y'\ :sub:`01`

       -  Y'\ :sub:`02`

       -  Y'\ :sub:`03`

    -  .. row 2

       -  start + 4:

       -  Y'\ :sub:`10`

       -  Y'\ :sub:`11`

       -  Y'\ :sub:`12`

       -  Y'\ :sub:`13`

    -  .. row 3

       -  start + 8:

       -  Y'\ :sub:`20`

       -  Y'\ :sub:`21`

       -  Y'\ :sub:`22`

       -  Y'\ :sub:`23`

    -  .. row 4

       -  start + 12:

       -  Y'\ :sub:`30`

       -  Y'\ :sub:`31`

       -  Y'\ :sub:`32`

       -  Y'\ :sub:`33`

    -  .. row 5

       -  start + 16:

       -  Cb\ :sub:`00`

       -  Cr\ :sub:`00`

       -  Cb\ :sub:`01`

       -  Cr\ :sub:`01`

    -  .. row 6

       -  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


    -  .. row 1

       -  
       -  0

       -  
       -  1

       -  2

       -  
       -  3

    -  .. row 2

       -  0

       -  Y

       -  
       -  Y

       -  Y

       -  
       -  Y

    -  .. row 3

       -  
       -  
       -  C

       -  
       -  
       -  C

       -  

    -  .. row 4

       -  1

       -  Y
       -  

       -  Y

       -  Y

       -  
       -  Y

    -  .. row 5

       -  

    -  .. row 6

       -  2

       -  Y
       -  

       -  Y

       -  Y

       -  
       -  Y

    -  .. row 7

       -  
       -  
       -  C

       -  
       -  
       -  C

       -  

    -  .. row 8

       -  3

       -  Y

       -  
       -  Y

       -  Y

       -  
       -  Y