130 lines
2.5 KiB
ReStructuredText
130 lines
2.5 KiB
ReStructuredText
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.. -*- coding: utf-8; mode: rst -*-
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.. _V4L2-PIX-FMT-NV12:
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.. _V4L2-PIX-FMT-NV21:
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******************************************************
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V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')
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******************************************************
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V4L2_PIX_FMT_NV21
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Formats with ½ horizontal and vertical chroma resolution, also known as
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YUV 4:2:0. One luminance and one chrominance plane with alternating
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chroma samples as opposed to ``V4L2_PIX_FMT_YVU420``
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Description
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===========
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These are two-plane versions of the YUV 4:2:0 format. The three
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components are separated into two sub-images or planes. The Y plane is
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first. The Y plane has one byte per pixel. For ``V4L2_PIX_FMT_NV12``, a
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combined CbCr plane immediately follows the Y plane in memory. The CbCr
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plane is the same width, in bytes, as the Y plane (and of the image),
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but is half as tall in pixels. Each CbCr pair belongs to four pixels.
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For example, Cb\ :sub:`0`/Cr\ :sub:`0` belongs to Y'\ :sub:`00`,
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Y'\ :sub:`01`, Y'\ :sub:`10`, Y'\ :sub:`11`. ``V4L2_PIX_FMT_NV21`` is
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the same except the Cb and Cr bytes are swapped, the CrCb plane starts
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with a Cr byte.
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If the Y plane has pad bytes after each row, then the CbCr plane has as
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many pad bytes after its rows.
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**Byte Order.**
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Each cell is one byte.
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.. flat-table::
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:header-rows: 0
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:stub-columns: 0
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* - start + 0:
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- Y'\ :sub:`00`
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- Y'\ :sub:`01`
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- Y'\ :sub:`02`
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- Y'\ :sub:`03`
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* - start + 4:
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- Y'\ :sub:`10`
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- Y'\ :sub:`11`
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- Y'\ :sub:`12`
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- Y'\ :sub:`13`
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* - start + 8:
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- Y'\ :sub:`20`
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- Y'\ :sub:`21`
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- Y'\ :sub:`22`
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- Y'\ :sub:`23`
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* - start + 12:
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- Y'\ :sub:`30`
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- Y'\ :sub:`31`
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- Y'\ :sub:`32`
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- Y'\ :sub:`33`
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* - start + 16:
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- Cb\ :sub:`00`
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- Cr\ :sub:`00`
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- Cb\ :sub:`01`
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- Cr\ :sub:`01`
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* - start + 20:
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- Cb\ :sub:`10`
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- Cr\ :sub:`10`
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- Cb\ :sub:`11`
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- Cr\ :sub:`11`
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**Color Sample Location..**
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.. flat-table::
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:header-rows: 0
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:stub-columns: 0
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* -
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- 0
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-
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- 1
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- 2
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-
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- 3
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* - 0
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- Y
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-
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- Y
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- Y
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-
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- Y
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* -
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-
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- C
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-
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-
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- C
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-
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* - 1
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- Y
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-
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- Y
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- Y
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-
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- Y
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* -
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* - 2
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- Y
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-
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- Y
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- Y
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-
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- Y
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* -
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-
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- C
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-
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-
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- C
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-
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* - 3
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- Y
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-
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- Y
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- Y
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-
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- Y
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