aboutsummaryrefslogtreecommitdiff
path: root/Documentation/DocBook/media/v4l/pixfmt-m420.xml
blob: ce4bc019e5c0351ee86ec12abff513571c9bf32f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
    <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 &frac12; 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 &frac12; 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 &frac12; 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 &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>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&nbsp;+&nbsp;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&nbsp;+&nbsp;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&nbsp;+&nbsp;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>

  <!--
Local Variables:
mode: sgml
sgml-parent-document: "pixfmt.sgml"
indent-tabs-mode: nil
End:
  -->