`V4L2_PIX_FMT_YUV420M`

— Variation of `V4L2_PIX_FMT_YUV420`

with planes non contiguous in memory.

This is a multi-planar format, as opposed to a packed format.
The three components are separated into three sub- images or planes.
The Y plane is first. The Y plane has one byte per pixel. The Cb data
constitutes the second plane which is half the width and half
the height of the Y plane (and of the image). Each Cb belongs to four
pixels, a two-by-two square of the image. For example,
Cb_{0} belongs to Y'_{00},
Y'_{01}, Y'_{10}, and
Y'_{11}. The Cr data, just like the Cb plane, is
in the third plane.

If the Y plane has pad bytes after each row, then the Cb and Cr planes have half as many pad bytes after their rows. In other words, two Cx rows (including padding) is exactly as long as one Y row (including padding).

`V4L2_PIX_FMT_YUV420M`

is intended to be
used only in drivers and applications that support the multi-planar API,
described in the section called “Single- and multi-planar APIs”.

**Example 2.22. V4L2_PIX_FMT_YUV420M 4 × 4
pixel image**

**Byte Order. **Each cell is one byte.

start0 + 0: | Y'_{00} | Y'_{01} | Y'_{02} | Y'_{03} |

start0 + 4: | Y'_{10} | Y'_{11} | Y'_{12} | Y'_{13} |

start0 + 8: | Y'_{20} | Y'_{21} | Y'_{22} | Y'_{23} |

start0 + 12: | Y'_{30} | Y'_{31} | Y'_{32} | Y'_{33} |

start1 + 0: | Cb_{00} | Cb_{01} | ||

start1 + 2: | Cb_{10} | Cb_{11} | ||

start2 + 0: | Cr_{00} | Cr_{01} | ||

start2 + 2: | Cr_{10} | Cr_{11} |

**Color Sample Location. **

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 |