140 lines
4.7 KiB
XML
140 lines
4.7 KiB
XML
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<refentry id="V4L2-PIX-FMT-M420">
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<refmeta>
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<refentrytitle>V4L2_PIX_FMT_M420 ('M420')</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname><constant>V4L2_PIX_FMT_M420</constant></refname>
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<refpurpose>Format with ½ horizontal and vertical chroma
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resolution, also known as YUV 4:2:0. Hybrid plane line-interleaved
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layout.</refpurpose>
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</refnamediv>
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<refsect1>
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<title>Description</title>
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<para>M420 is a YUV format with ½ horizontal and vertical chroma
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subsampling (YUV 4:2:0). Pixels are organized as interleaved luma and
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chroma planes. Two lines of luma data are followed by one line of chroma
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data.</para>
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<para>The luma plane has one byte per pixel. The chroma plane contains
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interleaved CbCr pixels subsampled by ½ in the horizontal and
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vertical directions. Each CbCr pair belongs to four pixels. For example,
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Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to
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Y'<subscript>00</subscript>, Y'<subscript>01</subscript>,
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Y'<subscript>10</subscript>, Y'<subscript>11</subscript>.</para>
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<para>All line lengths are identical: if the Y lines include pad bytes
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so do the CbCr lines.</para>
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<example>
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<title><constant>V4L2_PIX_FMT_M420</constant> 4 × 4
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pixel image</title>
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<formalpara>
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<title>Byte Order.</title>
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<para>Each cell is one byte.
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<informaltable frame="none">
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<tgroup cols="5" align="center">
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<colspec align="left" colwidth="2*" />
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<tbody valign="top">
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<row>
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<entry>start + 0:</entry>
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<entry>Y'<subscript>00</subscript></entry>
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<entry>Y'<subscript>01</subscript></entry>
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<entry>Y'<subscript>02</subscript></entry>
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<entry>Y'<subscript>03</subscript></entry>
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</row>
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<row>
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<entry>start + 4:</entry>
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<entry>Y'<subscript>10</subscript></entry>
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<entry>Y'<subscript>11</subscript></entry>
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<entry>Y'<subscript>12</subscript></entry>
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<entry>Y'<subscript>13</subscript></entry>
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</row>
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<row>
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<entry>start + 8:</entry>
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<entry>Cb<subscript>00</subscript></entry>
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<entry>Cr<subscript>00</subscript></entry>
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<entry>Cb<subscript>01</subscript></entry>
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<entry>Cr<subscript>01</subscript></entry>
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</row>
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<row>
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<entry>start + 16:</entry>
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<entry>Y'<subscript>20</subscript></entry>
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<entry>Y'<subscript>21</subscript></entry>
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<entry>Y'<subscript>22</subscript></entry>
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<entry>Y'<subscript>23</subscript></entry>
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</row>
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<row>
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<entry>start + 20:</entry>
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<entry>Y'<subscript>30</subscript></entry>
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<entry>Y'<subscript>31</subscript></entry>
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<entry>Y'<subscript>32</subscript></entry>
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<entry>Y'<subscript>33</subscript></entry>
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</row>
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<row>
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<entry>start + 24:</entry>
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<entry>Cb<subscript>10</subscript></entry>
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<entry>Cr<subscript>10</subscript></entry>
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<entry>Cb<subscript>11</subscript></entry>
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<entry>Cr<subscript>11</subscript></entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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</formalpara>
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<formalpara>
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<title>Color Sample Location.</title>
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<para>
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<informaltable frame="none">
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<tgroup cols="7" align="center">
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<tbody valign="top">
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<row>
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<entry></entry>
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<entry>0</entry><entry></entry><entry>1</entry><entry></entry>
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<entry>2</entry><entry></entry><entry>3</entry>
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</row>
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<row>
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<entry>0</entry>
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<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
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<entry>Y</entry><entry></entry><entry>Y</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry><entry>C</entry><entry></entry><entry></entry>
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<entry></entry><entry>C</entry><entry></entry>
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</row>
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<row>
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<entry>1</entry>
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<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
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<entry>Y</entry><entry></entry><entry>Y</entry>
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</row>
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<row>
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<entry></entry>
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</row>
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<row>
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<entry>2</entry>
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<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
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<entry>Y</entry><entry></entry><entry>Y</entry>
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</row>
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<row>
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<entry></entry>
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<entry></entry><entry>C</entry><entry></entry><entry></entry>
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<entry></entry><entry>C</entry><entry></entry>
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</row>
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<row>
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<entry>3</entry>
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<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
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<entry>Y</entry><entry></entry><entry>Y</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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</formalpara>
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</example>
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</refsect1>
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</refentry>
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