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authorSylwester Nawrocki <s.nawrocki@samsung.com>2011-01-09 07:01:10 -0500
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-03-21 19:31:35 -0400
commit269da4027c9a3466150308a9fe5f2a3a58336cd8 (patch)
tree6b94305caee3a233201852c834b5ba73d7ec5473 /Documentation/DocBook/v4l/pixfmt-yuv420m.xml
parent4a3c9b4f0df43207eb0b4d0da9cb51e185506bd5 (diff)
[media] v4l: Add DocBook documentation for YU12M, NV12M image formats
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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1 <refentry id="V4L2-PIX-FMT-YUV420M">
2 <refmeta>
3 <refentrytitle>V4L2_PIX_FMT_YUV420M ('YU12M')</refentrytitle>
4 &manvol;
5 </refmeta>
6 <refnamediv>
7 <refname> <constant>V4L2_PIX_FMT_YUV420M</constant></refname>
8 <refpurpose>Variation of <constant>V4L2_PIX_FMT_YUV420</constant>
9 with planes non contiguous in memory. </refpurpose>
10 </refnamediv>
11
12 <refsect1>
13 <title>Description</title>
14
15 <para>This is a multi-planar format, as opposed to a packed format.
16The three components are separated into three sub- images or planes.
17
18The Y plane is first. The Y plane has one byte per pixel. The Cb data
19constitutes the second plane which is half the width and half
20the height of the Y plane (and of the image). Each Cb belongs to four
21pixels, a two-by-two square of the image. For example,
22Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>,
23Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and
24Y'<subscript>11</subscript>. The Cr data, just like the Cb plane, is
25in the third plane. </para>
26
27 <para>If the Y plane has pad bytes after each row, then the Cb
28and Cr planes have half as many pad bytes after their rows. In other
29words, two Cx rows (including padding) is exactly as long as one Y row
30(including padding).</para>
31
32 <para><constant>V4L2_PIX_FMT_NV12M</constant> is intended to be
33used only in drivers and applications that support the multi-planar API,
34described in <xref linkend="planar-apis"/>. </para>
35
36 <example>
37 <title><constant>V4L2_PIX_FMT_YVU420M</constant> 4 &times; 4
38pixel image</title>
39
40 <formalpara>
41 <title>Byte Order.</title>
42 <para>Each cell is one byte.
43 <informaltable frame="none">
44 <tgroup cols="5" align="center">
45 <colspec align="left" colwidth="2*" />
46 <tbody valign="top">
47 <row>
48 <entry>start0&nbsp;+&nbsp;0:</entry>
49 <entry>Y'<subscript>00</subscript></entry>
50 <entry>Y'<subscript>01</subscript></entry>
51 <entry>Y'<subscript>02</subscript></entry>
52 <entry>Y'<subscript>03</subscript></entry>
53 </row>
54 <row>
55 <entry>start0&nbsp;+&nbsp;4:</entry>
56 <entry>Y'<subscript>10</subscript></entry>
57 <entry>Y'<subscript>11</subscript></entry>
58 <entry>Y'<subscript>12</subscript></entry>
59 <entry>Y'<subscript>13</subscript></entry>
60 </row>
61 <row>
62 <entry>start0&nbsp;+&nbsp;8:</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>start0&nbsp;+&nbsp;12:</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><entry></entry></row>
76 <row>
77 <entry>start1&nbsp;+&nbsp;0:</entry>
78 <entry>Cb<subscript>00</subscript></entry>
79 <entry>Cb<subscript>01</subscript></entry>
80 </row>
81 <row>
82 <entry>start1&nbsp;+&nbsp;2:</entry>
83 <entry>Cb<subscript>10</subscript></entry>
84 <entry>Cb<subscript>11</subscript></entry>
85 </row>
86 <row><entry></entry></row>
87 <row>
88 <entry>start2&nbsp;+&nbsp;0:</entry>
89 <entry>Cr<subscript>00</subscript></entry>
90 <entry>Cr<subscript>01</subscript></entry>
91 </row>
92 <row>
93 <entry>start2&nbsp;+&nbsp;2:</entry>
94 <entry>Cr<subscript>10</subscript></entry>
95 <entry>Cr<subscript>11</subscript></entry>
96 </row>
97 </tbody>
98 </tgroup>
99 </informaltable>
100 </para>
101 </formalpara>
102
103 <formalpara>
104 <title>Color Sample Location.</title>
105 <para>
106 <informaltable frame="none">
107 <tgroup cols="7" align="center">
108 <tbody valign="top">
109 <row>
110 <entry></entry>
111 <entry>0</entry><entry></entry><entry>1</entry><entry></entry>
112 <entry>2</entry><entry></entry><entry>3</entry>
113 </row>
114 <row>
115 <entry>0</entry>
116 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
117 <entry>Y</entry><entry></entry><entry>Y</entry>
118 </row>
119 <row>
120 <entry></entry>
121 <entry></entry><entry>C</entry><entry></entry><entry></entry>
122 <entry></entry><entry>C</entry><entry></entry>
123 </row>
124 <row>
125 <entry>1</entry>
126 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
127 <entry>Y</entry><entry></entry><entry>Y</entry>
128 </row>
129 <row>
130 <entry></entry>
131 </row>
132 <row>
133 <entry>2</entry>
134 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
135 <entry>Y</entry><entry></entry><entry>Y</entry>
136 </row>
137 <row>
138 <entry></entry>
139 <entry></entry><entry>C</entry><entry></entry><entry></entry>
140 <entry></entry><entry>C</entry><entry></entry>
141 </row>
142 <row>
143 <entry>3</entry>
144 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
145 <entry>Y</entry><entry></entry><entry>Y</entry>
146 </row>
147 </tbody>
148 </tgroup>
149 </informaltable>
150 </para>
151 </formalpara>
152 </example>
153 </refsect1>
154 </refentry>
155
156 <!--
157Local Variables:
158mode: sgml
159sgml-parent-document: "pixfmt.sgml"
160indent-tabs-mode: nil
161End:
162 -->
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-01 16:31:39 -0400