1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _V4L2-PIX-FMT-NV12MT: 4 5**************************** 6V4L2_PIX_FMT_NV12MT ('TM12') 7**************************** 8 9Formats with ½ horizontal and vertical chroma resolution. This format 10has two planes - one for luminance and one for chrominance. Chroma 11samples are interleaved. The difference to ``V4L2_PIX_FMT_NV12`` is the 12memory layout. Pixels are grouped in macroblocks of 64x32 size. The 13order of macroblocks in memory is also not standard. 14 15 16Description 17=========== 18 19This is the two-plane versions of the YUV 4:2:0 format where data is 20grouped into 64x32 macroblocks. The three components are separated into 21two sub-images or planes. The Y plane has one byte per pixel and pixels 22are grouped into 64x32 macroblocks. The CbCr plane has the same width, 23in bytes, as the Y plane (and the image), but is half as tall in pixels. 24The chroma plane is also grouped into 64x32 macroblocks. 25 26Width of the buffer has to be aligned to the multiple of 128, and height 27alignment is 32. Every four adjacent buffers - two horizontally and two 28vertically are grouped together and are located in memory in Z or 29flipped Z order. 30 31Layout of macroblocks in memory is presented in the following figure. 32 33 34.. _nv12mt: 35 36.. kernel-figure:: nv12mt.svg 37 :alt: nv12mt.svg 38 :align: center 39 40 V4L2_PIX_FMT_NV12MT macroblock Z shape memory layout 41 42The requirement that width is multiple of 128 is implemented because, 43the Z shape cannot be cut in half horizontally. In case the vertical 44resolution of macroblocks is odd then the last row of macroblocks is 45arranged in a linear order. 46 47In case of chroma the layout is identical. Cb and Cr samples are 48interleaved. Height of the buffer is aligned to 32. 49 50 51.. _nv12mt_ex: 52 53.. kernel-figure:: nv12mt_example.svg 54 :alt: nv12mt_example.svg 55 :align: center 56 57 Example V4L2_PIX_FMT_NV12MT memory layout of macroblocks 58 59Memory layout of macroblocks of ``V4L2_PIX_FMT_NV12MT`` format in most 60extreme case. 61
