path: root/Documentation/DocBook/media/v4l/pixfmt-yuv411p.xml

    <refentry id="V4L2-PIX-FMT-YUV411P">
      <refmeta>
	<refentrytitle>V4L2_PIX_FMT_YUV411P ('411P')</refentrytitle>
	&manvol;
      </refmeta>
      <refnamediv>
	<refname><constant>V4L2_PIX_FMT_YUV411P</constant></refname>
	<refpurpose>Format with &frac14; horizontal chroma resolution,
also known as YUV 4:1:1. Planar layout as opposed to
<constant>V4L2_PIX_FMT_Y41P</constant></refpurpose>
      </refnamediv>
      <refsect1>
	<title>Description</title>

	<para>This format is not commonly used. This is a planar
format similar to the 4:2:2 planar format except with half as many
chroma. The three components are separated into three sub-images or
planes. The Y plane is first. The Y plane has one byte per pixel. The
Cb plane immediately follows the Y plane in memory. The Cb plane is
&frac14; the width of the Y plane (and of the image). Each Cb belongs
to 4 pixels all on the same row. For example,
Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>,
Y'<subscript>01</subscript>, Y'<subscript>02</subscript> and
Y'<subscript>03</subscript>. Following the Cb plane is the Cr plane,
just like the Cb plane.</para>

	<para>If the Y plane has pad bytes after each row, then the Cr
and Cb planes have &frac14; as many pad bytes after their rows. In
other words, four C x rows (including padding) is exactly as long as
one Y row (including padding).</para>

	<example>
	  <title><constant>V4L2_PIX_FMT_YUV411P</constant> 4 &times; 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&nbsp;+&nbsp;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&nbsp;+&nbsp;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&nbsp;+&nbsp;8:</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&nbsp;+&nbsp;12:</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&nbsp;+&nbsp;16:</entry>
		      <entry>Cb<subscript>00</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;17:</entry>
		      <entry>Cb<subscript>10</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;18:</entry>
		      <entry>Cb<subscript>20</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;19:</entry>
		      <entry>Cb<subscript>30</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;20:</entry>
		      <entry>Cr<subscript>00</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;21:</entry>
		      <entry>Cr<subscript>10</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;22:</entry>
		      <entry>Cr<subscript>20</subscript></entry>
		    </row>
		    <row>
		      <entry>start&nbsp;+&nbsp;23:</entry>
		      <entry>Cr<subscript>30</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>C</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry>
		    </row>
		    <row>
		      <entry>1</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry>
		    </row>
		    <row>
		      <entry>2</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry>
		    </row>
		    <row>
		      <entry>3</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
		      <entry>Y</entry><entry></entry><entry>Y</entry>
		    </row>
		  </tbody>
		</tgroup>
		</informaltable>
	      </para>
	  </formalpara>
	</example>
      </refsect1>
    </refentry>

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