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Based on kernel version 3.16. Page generated on 2014-08-06 21:38 EST.

1	    <refentry id="V4L2-PIX-FMT-M420">
2	      <refmeta>
3		<refentrytitle>V4L2_PIX_FMT_M420 ('M420')</refentrytitle>
4		&manvol;
5	      </refmeta>
6	      <refnamediv>
7		<refname><constant>V4L2_PIX_FMT_M420</constant></refname>
8		<refpurpose>Format with &frac12; horizontal and vertical chroma
9		resolution, also known as YUV 4:2:0. Hybrid plane line-interleaved
10		layout.</refpurpose>
11	      </refnamediv>
12	      <refsect1>
13		<title>Description</title>
14	
15		<para>M420 is a YUV format with &frac12; horizontal and vertical chroma
16		subsampling (YUV 4:2:0). Pixels are organized as interleaved luma and
17		chroma planes. Two lines of luma data are followed by one line of chroma
18		data.</para>
19		<para>The luma plane has one byte per pixel. The chroma plane contains
20		interleaved CbCr pixels subsampled by &frac12; in the horizontal and
21		vertical directions. Each CbCr pair belongs to four pixels. For example,
22	Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to
23	Y'<subscript>00</subscript>, Y'<subscript>01</subscript>,
24	Y'<subscript>10</subscript>, Y'<subscript>11</subscript>.</para>
25	
26		<para>All line lengths are identical: if the Y lines include pad bytes
27		so do the CbCr lines.</para>
28	
29		<example>
30		  <title><constant>V4L2_PIX_FMT_M420</constant> 4 &times; 4
31	pixel image</title>
32	
33		  <formalpara>
34		    <title>Byte Order.</title>
35		    <para>Each cell is one byte.
36			<informaltable frame="none">
37			<tgroup cols="5" align="center">
38			  <colspec align="left" colwidth="2*" />
39			  <tbody valign="top">
40			    <row>
41			      <entry>start&nbsp;+&nbsp;0:</entry>
42			      <entry>Y'<subscript>00</subscript></entry>
43			      <entry>Y'<subscript>01</subscript></entry>
44			      <entry>Y'<subscript>02</subscript></entry>
45			      <entry>Y'<subscript>03</subscript></entry>
46			    </row>
47			    <row>
48			      <entry>start&nbsp;+&nbsp;4:</entry>
49			      <entry>Y'<subscript>10</subscript></entry>
50			      <entry>Y'<subscript>11</subscript></entry>
51			      <entry>Y'<subscript>12</subscript></entry>
52			      <entry>Y'<subscript>13</subscript></entry>
53			    </row>
54			    <row>
55			      <entry>start&nbsp;+&nbsp;8:</entry>
56			      <entry>Cb<subscript>00</subscript></entry>
57			      <entry>Cr<subscript>00</subscript></entry>
58			      <entry>Cb<subscript>01</subscript></entry>
59			      <entry>Cr<subscript>01</subscript></entry>
60			    </row>
61			    <row>
62			      <entry>start&nbsp;+&nbsp;16:</entry>
63			      <entry>Y'<subscript>20</subscript></entry>
64			      <entry>Y'<subscript>21</subscript></entry>
65			      <entry>Y'<subscript>22</subscript></entry>
66			      <entry>Y'<subscript>23</subscript></entry>
67			    </row>
68			    <row>
69			      <entry>start&nbsp;+&nbsp;20:</entry>
70			      <entry>Y'<subscript>30</subscript></entry>
71			      <entry>Y'<subscript>31</subscript></entry>
72			      <entry>Y'<subscript>32</subscript></entry>
73			      <entry>Y'<subscript>33</subscript></entry>
74			    </row>
75			    <row>
76			      <entry>start&nbsp;+&nbsp;24:</entry>
77			      <entry>Cb<subscript>10</subscript></entry>
78			      <entry>Cr<subscript>10</subscript></entry>
79			      <entry>Cb<subscript>11</subscript></entry>
80			      <entry>Cr<subscript>11</subscript></entry>
81			    </row>
82			  </tbody>
83			</tgroup>
84			</informaltable>
85		      </para>
86		  </formalpara>
87	
88		  <formalpara>
89		    <title>Color Sample Location.</title>
90		    <para>
91			<informaltable frame="none">
92			<tgroup cols="7" align="center">
93			  <tbody valign="top">
94			    <row>
95			      <entry></entry>
96			      <entry>0</entry><entry></entry><entry>1</entry><entry></entry>
97			      <entry>2</entry><entry></entry><entry>3</entry>
98			    </row>
99			    <row>
100			      <entry>0</entry>
101			      <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
102			      <entry>Y</entry><entry></entry><entry>Y</entry>
103			    </row>
104			    <row>
105			      <entry></entry>
106			      <entry></entry><entry>C</entry><entry></entry><entry></entry>
107			      <entry></entry><entry>C</entry><entry></entry>
108			    </row>
109			    <row>
110			      <entry>1</entry>
111			      <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
112			      <entry>Y</entry><entry></entry><entry>Y</entry>
113			    </row>
114			    <row>
115			      <entry></entry>
116			    </row>
117			    <row>
118			      <entry>2</entry>
119			      <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
120			      <entry>Y</entry><entry></entry><entry>Y</entry>
121			    </row>
122			    <row>
123			      <entry></entry>
124			      <entry></entry><entry>C</entry><entry></entry><entry></entry>
125			      <entry></entry><entry>C</entry><entry></entry>
126			    </row>
127			    <row>
128			      <entry>3</entry>
129			      <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
130			      <entry>Y</entry><entry></entry><entry>Y</entry>
131			    </row>
132			  </tbody>
133			</tgroup>
134			</informaltable>
135		      </para>
136		  </formalpara>
137		</example>
138	      </refsect1>
139	    </refentry>
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