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