2.10.24. V4L2_PIX_FMT_NV12M (‘NM12’), V4L2_PIX_FMT_NV21M (‘NM21’), V4L2_PIX_FMT_NV12MT_16X16¶
V4L2_PIX_FMT_NV21 with planes
non contiguous in memory.
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, Cb0/Cr0 belongs to
Y’00, Y’01, Y’10, Y’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
V4L2_PIX_FMT_NV21M is the same as
except the Cb and Cr bytes are swapped, the CrCb plane starts with a Cr
V4L2_PIX_FMT_NV12M is intended to be used only in drivers and
applications that support the multi-planar API, described in
Single- and multi-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.
|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:||Cb00||Cr00||Cb01||Cr01|
|start1 + 4:||Cb10||Cr10||Cb11||Cr11|
Color Sample Location..