Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 60 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst b/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst
new file mode 100644
index 000000000..172a38256
--- /dev/null
+++ b/Documentation/media/uapi/v4l/pixfmt-nv12mt.rst
@@ -0,0 +1,60 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _V4L2-PIX-FMT-NV12MT:
+
+****************************
+V4L2_PIX_FMT_NV12MT ('TM12')
+****************************
+
+Formats with ½ horizontal and vertical chroma resolution. This format
+has two planes - one for luminance and one for chrominance. Chroma
+samples are interleaved. The difference to ``V4L2_PIX_FMT_NV12`` is the
+memory layout. Pixels are grouped in macroblocks of 64x32 size. The
+order of macroblocks in memory is also not standard.
+
+
+Description
+===========
+
+This is the two-plane versions of the YUV 4:2:0 format where data is
+grouped into 64x32 macroblocks. The three components are separated into
+two sub-images or planes. The Y plane has one byte per pixel and pixels
+are grouped into 64x32 macroblocks. The CbCr plane has the same width,
+in bytes, as the Y plane (and the image), but is half as tall in pixels.
+The chroma plane is also grouped into 64x32 macroblocks.
+
+Width of the buffer has to be aligned to the multiple of 128, and height
+alignment is 32. Every four adjacent buffers - two horizontally and two
+vertically are grouped together and are located in memory in Z or
+flipped Z order.
+
+Layout of macroblocks in memory is presented in the following figure.
+
+
+.. _nv12mt:
+
+.. kernel-figure:: nv12mt.svg
+    :alt:    nv12mt.svg
+    :align:  center
+
+    V4L2_PIX_FMT_NV12MT macroblock Z shape memory layout
+
+The requirement that width is multiple of 128 is implemented because,
+the Z shape cannot be cut in half horizontally. In case the vertical
+resolution of macroblocks is odd then the last row of macroblocks is
+arranged in a linear order.
+
+In case of chroma the layout is identical. Cb and Cr samples are
+interleaved. Height of the buffer is aligned to 32.
+
+
+.. _nv12mt_ex:
+
+.. kernel-figure:: nv12mt_example.svg
+    :alt:    nv12mt_example.svg
+    :align:  center
+
+    Example V4L2_PIX_FMT_NV12MT memory layout of macroblocks
+
+Memory layout of macroblocks of ``V4L2_PIX_FMT_NV12MT`` format in most
+extreme case.