2.6.24. V4L2_PIX_FMT_NV12M (‘NM12’), V4L2_PIX_FMT_NV21M (‘NM21’), V4L2_PIX_FMT_NV12MT_16X16

V4L2_PIX_FMT_NV21M V4L2_PIX_FMT_NV12MT_16X16 Variation of V4L2_PIX_FMT_NV12 and V4L2_PIX_FMT_NV21 with planes non contiguous in memory. Description

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 memory. V4L2_PIX_FMT_NV21M is the same as V4L2_PIX_FMT_NV12M except the Cb and Cr bytes are swapped, the CrCb plane starts with a Cr byte.

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:

  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