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diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst new file mode 100644 index 000000000000..80c14d4f5acb --- /dev/null +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst @@ -0,0 +1,159 @@ +.. Permission is granted to copy, distribute and/or modify this +.. document under the terms of the GNU Free Documentation License, +.. Version 1.1 or any later version published by the Free Software +.. Foundation, with no Invariant Sections, no Front-Cover Texts +.. and no Back-Cover Texts. A copy of the license is included at +.. Documentation/userspace-api/media/fdl-appendix.rst. +.. +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections + +.. _V4L2-PIX-FMT-YUV420M: +.. _v4l2-pix-fmt-yvu420m: + +************************************************************ +V4L2_PIX_FMT_YUV420M ('YM12'), V4L2_PIX_FMT_YVU420M ('YM21') +************************************************************ + + +V4L2_PIX_FMT_YVU420M +Variation of ``V4L2_PIX_FMT_YUV420`` and ``V4L2_PIX_FMT_YVU420`` with +planes non contiguous in memory. + + +Description +=========== + +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. For +``V4L2_PIX_FMT_YUV420M`` 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\ :sub:`0` belongs to Y'\ :sub:`00`, Y'\ :sub:`01`, +Y'\ :sub:`10`, and Y'\ :sub:`11`. The Cr data, just like the Cb plane, +is in the third plane. + +``V4L2_PIX_FMT_YVU420M`` is the same except the Cr data is stored in the +second plane and the Cb data 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`` and ``V4L2_PIX_FMT_YVU420M`` are intended to be +used only in drivers and applications that support the multi-planar API, +described in :ref:`planar-apis`. + +**Byte Order.** +Each cell is one byte. + + + + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + * - start0 + 0: + - Y'\ :sub:`00` + - Y'\ :sub:`01` + - Y'\ :sub:`02` + - Y'\ :sub:`03` + * - start0 + 4: + - Y'\ :sub:`10` + - Y'\ :sub:`11` + - Y'\ :sub:`12` + - Y'\ :sub:`13` + * - start0 + 8: + - Y'\ :sub:`20` + - Y'\ :sub:`21` + - Y'\ :sub:`22` + - Y'\ :sub:`23` + * - start0 + 12: + - Y'\ :sub:`30` + - Y'\ :sub:`31` + - Y'\ :sub:`32` + - Y'\ :sub:`33` + * - + * - start1 + 0: + - Cb\ :sub:`00` + - Cb\ :sub:`01` + * - start1 + 2: + - Cb\ :sub:`10` + - Cb\ :sub:`11` + * - + * - start2 + 0: + - Cr\ :sub:`00` + - Cr\ :sub:`01` + * - start2 + 2: + - Cr\ :sub:`10` + - Cr\ :sub:`11` + + +**Color Sample Location:** + + + +.. flat-table:: + :header-rows: 0 + :stub-columns: 0 + + * - + - 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 |