Documentation/DocBook/v4l/pixfmt-yuv422p.xml

   1     <refentry id="V4L2-PIX-FMT-YUV422P">
   2       <refmeta>
   3         <refentrytitle>V4L2_PIX_FMT_YUV422P ('422P')</refentrytitle>
   4         &manvol;
   5       </refmeta>
   6       <refnamediv>
   7         <refname><constant>V4L2_PIX_FMT_YUV422P</constant></refname>
   8         <refpurpose>Format with &frac12; horizontal chroma resolution,
   9 also known as YUV 4:2:2. Planar layout as opposed to
  10 <constant>V4L2_PIX_FMT_YUYV</constant></refpurpose>
  11       </refnamediv>
  12       <refsect1>
  13         <title>Description</title>
  14
  15         <para>This format is not commonly used. This is a planar
  16 version of the YUYV format. The three components are separated into
  17 three sub-images or planes. The Y plane is first. The Y plane has one
  18 byte per pixel. The Cb plane immediately follows the Y plane in
  19 memory. The Cb plane is half the width of the Y plane (and of the
  20 image). Each Cb belongs to two pixels. For example,
  21 Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>,
  22 Y'<subscript>01</subscript>. Following the Cb plane is the Cr plane,
  23 just like the Cb plane.</para>
  24
  25         <para>If the Y plane has pad bytes after each row, then the Cr
  26 and Cb planes have half as many pad bytes after their rows. In other
  27 words, two Cx rows (including padding) is exactly as long as one Y row
  28 (including padding).</para>
  29
  30         <example>
  31           <title><constant>V4L2_PIX_FMT_YUV422P</constant> 4 &times; 4
  32 pixel image</title>
  33
  34           <formalpara>
  35             <title>Byte Order.</title>
  36             <para>Each cell is one byte.
  37                 <informaltable frame="none">
  38                 <tgroup cols="5" align="center">
  39                   <colspec align="left" colwidth="2*" />
  40                   <tbody valign="top">
  41                     <row>
  42                       <entry>start&nbsp;+&nbsp;0:</entry>
  43                       <entry>Y'<subscript>00</subscript></entry>
  44                       <entry>Y'<subscript>01</subscript></entry>
  45                       <entry>Y'<subscript>02</subscript></entry>
  46                       <entry>Y'<subscript>03</subscript></entry>
  47                     </row>
  48                     <row>
  49                       <entry>start&nbsp;+&nbsp;4:</entry>
  50                       <entry>Y'<subscript>10</subscript></entry>
  51                       <entry>Y'<subscript>11</subscript></entry>
  52                       <entry>Y'<subscript>12</subscript></entry>
  53                       <entry>Y'<subscript>13</subscript></entry>
  54                     </row>
  55                     <row>
  56                       <entry>start&nbsp;+&nbsp;8:</entry>
  57                       <entry>Y'<subscript>20</subscript></entry>
  58                       <entry>Y'<subscript>21</subscript></entry>
  59                       <entry>Y'<subscript>22</subscript></entry>
  60                       <entry>Y'<subscript>23</subscript></entry>
  61                     </row>
  62                     <row>
  63                       <entry>start&nbsp;+&nbsp;12:</entry>
  64                       <entry>Y'<subscript>30</subscript></entry>
  65                       <entry>Y'<subscript>31</subscript></entry>
  66                       <entry>Y'<subscript>32</subscript></entry>
  67                       <entry>Y'<subscript>33</subscript></entry>
  68                     </row>
  69                     <row>
  70                       <entry>start&nbsp;+&nbsp;16:</entry>
  71                       <entry>Cb<subscript>00</subscript></entry>
  72                       <entry>Cb<subscript>01</subscript></entry>
  73                     </row>
  74                     <row>
  75                       <entry>start&nbsp;+&nbsp;18:</entry>
  76                       <entry>Cb<subscript>10</subscript></entry>
  77                       <entry>Cb<subscript>11</subscript></entry>
  78                     </row>
  79                     <row>
  80                       <entry>start&nbsp;+&nbsp;20:</entry>
  81                       <entry>Cb<subscript>20</subscript></entry>
  82                       <entry>Cb<subscript>21</subscript></entry>
  83                     </row>
  84                     <row>
  85                       <entry>start&nbsp;+&nbsp;22:</entry>
  86                       <entry>Cb<subscript>30</subscript></entry>
  87                       <entry>Cb<subscript>31</subscript></entry>
  88                     </row>
  89                     <row>
  90                       <entry>start&nbsp;+&nbsp;24:</entry>
  91                       <entry>Cr<subscript>00</subscript></entry>
  92                       <entry>Cr<subscript>01</subscript></entry>
  93                     </row>
  94                     <row>
  95                       <entry>start&nbsp;+&nbsp;26:</entry>
  96                       <entry>Cr<subscript>10</subscript></entry>
  97                       <entry>Cr<subscript>11</subscript></entry>
  98                     </row>
  99                     <row>
 100                       <entry>start&nbsp;+&nbsp;28:</entry>
 101                       <entry>Cr<subscript>20</subscript></entry>
 102                       <entry>Cr<subscript>21</subscript></entry>
 103                     </row>
 104                     <row>
 105                       <entry>start&nbsp;+&nbsp;30:</entry>
 106                       <entry>Cr<subscript>30</subscript></entry>
 107                       <entry>Cr<subscript>31</subscript></entry>
 108                     </row>
 109                   </tbody>
 110                 </tgroup>
 111                 </informaltable>
 112               </para>
 113           </formalpara>
 114
 115           <formalpara>
 116             <title>Color Sample Location.</title>
 117             <para>
 118                 <informaltable frame="none">
 119                 <tgroup cols="7" align="center">
 120                   <tbody valign="top">
 121                     <row>
 122                       <entry></entry>
 123                       <entry>0</entry><entry></entry><entry>1</entry><entry></entry>
 124                       <entry>2</entry><entry></entry><entry>3</entry>
 125                     </row>
 126                     <row>
 127                       <entry>0</entry>
 128                       <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry>
 129                       <entry>Y</entry><entry>C</entry><entry>Y</entry>
 130                     </row>
 131                     <row>
 132                       <entry>1</entry>
 133                       <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry>
 134                       <entry>Y</entry><entry>C</entry><entry>Y</entry>
 135                     </row>
 136                     <row>
 137                       <entry>2</entry>
 138                       <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry>
 139                       <entry>Y</entry><entry>C</entry><entry>Y</entry>
 140                     </row>
 141                     <row>
 142                       <entry>3</entry>
 143                       <entry>Y</entry><entry>C</entry><entry>Y</entry><entry></entry>
 144                       <entry>Y</entry><entry>C</entry><entry>Y</entry>
 145                     </row>
 146                   </tbody>
 147                 </tgroup>
 148                 </informaltable>
 149               </para>
 150           </formalpara>
 151         </example>
 152       </refsect1>
 153     </refentry>
 154
 155   <!--
 156 Local Variables:
 157 mode: sgml
 158 sgml-parent-document: "pixfmt.sgml"
 159 indent-tabs-mode: nil
 160 End:
 161   -->