Documentation/DocBook/v4l/pixfmt-yuv411p.xml

   1     <refentry id="V4L2-PIX-FMT-YUV411P">
   2       <refmeta>
   3         <refentrytitle>V4L2_PIX_FMT_YUV411P ('411P')</refentrytitle>
   4         &manvol;
   5       </refmeta>
   6       <refnamediv>
   7         <refname><constant>V4L2_PIX_FMT_YUV411P</constant></refname>
   8         <refpurpose>Format with &frac14; horizontal chroma resolution,
   9 also known as YUV 4:1:1. Planar layout as opposed to
  10 <constant>V4L2_PIX_FMT_Y41P</constant></refpurpose>
  11       </refnamediv>
  12       <refsect1>
  13         <title>Description</title>
  14
  15         <para>This format is not commonly used. This is a planar
  16 format similar to the 4:2:2 planar format except with half as many
  17 chroma. The three components are separated into three sub-images or
  18 planes. The Y plane is first. The Y plane has one byte per pixel. The
  19 Cb plane immediately follows the Y plane in memory. The Cb plane is
  20 &frac14; the width of the Y plane (and of the image). Each Cb belongs
  21 to 4 pixels all on the same row. For example,
  22 Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>,
  23 Y'<subscript>01</subscript>, Y'<subscript>02</subscript> and
  24 Y'<subscript>03</subscript>. Following the Cb plane is the Cr plane,
  25 just like the Cb plane.</para>
  26
  27         <para>If the Y plane has pad bytes after each row, then the Cr
  28 and Cb planes have &frac14; as many pad bytes after their rows. In
  29 other words, four C x rows (including padding) is exactly as long as
  30 one Y row (including padding).</para>
  31
  32         <example>
  33           <title><constant>V4L2_PIX_FMT_YUV411P</constant> 4 &times; 4
  34 pixel image</title>
  35
  36           <formalpara>
  37             <title>Byte Order.</title>
  38             <para>Each cell is one byte.
  39                 <informaltable frame="none">
  40                 <tgroup cols="5" align="center">
  41                   <colspec align="left" colwidth="2*" />
  42                   <tbody valign="top">
  43                     <row>
  44                       <entry>start&nbsp;+&nbsp;0:</entry>
  45                       <entry>Y'<subscript>00</subscript></entry>
  46                       <entry>Y'<subscript>01</subscript></entry>
  47                       <entry>Y'<subscript>02</subscript></entry>
  48                       <entry>Y'<subscript>03</subscript></entry>
  49                     </row>
  50                     <row>
  51                       <entry>start&nbsp;+&nbsp;4:</entry>
  52                       <entry>Y'<subscript>10</subscript></entry>
  53                       <entry>Y'<subscript>11</subscript></entry>
  54                       <entry>Y'<subscript>12</subscript></entry>
  55                       <entry>Y'<subscript>13</subscript></entry>
  56                     </row>
  57                     <row>
  58                       <entry>start&nbsp;+&nbsp;8:</entry>
  59                       <entry>Y'<subscript>20</subscript></entry>
  60                       <entry>Y'<subscript>21</subscript></entry>
  61                       <entry>Y'<subscript>22</subscript></entry>
  62                       <entry>Y'<subscript>23</subscript></entry>
  63                     </row>
  64                     <row>
  65                       <entry>start&nbsp;+&nbsp;12:</entry>
  66                       <entry>Y'<subscript>30</subscript></entry>
  67                       <entry>Y'<subscript>31</subscript></entry>
  68                       <entry>Y'<subscript>32</subscript></entry>
  69                       <entry>Y'<subscript>33</subscript></entry>
  70                     </row>
  71                     <row>
  72                       <entry>start&nbsp;+&nbsp;16:</entry>
  73                       <entry>Cb<subscript>00</subscript></entry>
  74                     </row>
  75                     <row>
  76                       <entry>start&nbsp;+&nbsp;17:</entry>
  77                       <entry>Cb<subscript>10</subscript></entry>
  78                     </row>
  79                     <row>
  80                       <entry>start&nbsp;+&nbsp;18:</entry>
  81                       <entry>Cb<subscript>20</subscript></entry>
  82                     </row>
  83                     <row>
  84                       <entry>start&nbsp;+&nbsp;19:</entry>
  85                       <entry>Cb<subscript>30</subscript></entry>
  86                     </row>
  87                     <row>
  88                       <entry>start&nbsp;+&nbsp;20:</entry>
  89                       <entry>Cr<subscript>00</subscript></entry>
  90                     </row>
  91                     <row>
  92                       <entry>start&nbsp;+&nbsp;21:</entry>
  93                       <entry>Cr<subscript>10</subscript></entry>
  94                     </row>
  95                     <row>
  96                       <entry>start&nbsp;+&nbsp;22:</entry>
  97                       <entry>Cr<subscript>20</subscript></entry>
  98                     </row>
  99                     <row>
 100                       <entry>start&nbsp;+&nbsp;23:</entry>
 101                       <entry>Cr<subscript>30</subscript></entry>
 102                     </row>
 103                   </tbody>
 104                 </tgroup>
 105                 </informaltable>
 106               </para>
 107           </formalpara>
 108
 109           <formalpara>
 110             <title>Color Sample Location.</title>
 111             <para>
 112                 <informaltable frame="none">
 113                 <tgroup cols="7" align="center">
 114                   <tbody valign="top">
 115                     <row>
 116                       <entry></entry>
 117                       <entry>0</entry><entry></entry><entry>1</entry><entry></entry>
 118                       <entry>2</entry><entry></entry><entry>3</entry>
 119                     </row>
 120                     <row>
 121                       <entry>0</entry>
 122                       <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
 123                       <entry>Y</entry><entry></entry><entry>Y</entry>
 124                     </row>
 125                     <row>
 126                       <entry>1</entry>
 127                       <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
 128                       <entry>Y</entry><entry></entry><entry>Y</entry>
 129                     </row>
 130                     <row>
 131                       <entry>2</entry>
 132                       <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
 133                       <entry>Y</entry><entry></entry><entry>Y</entry>
 134                     </row>
 135                     <row>
 136                       <entry>3</entry>
 137                       <entry>Y</entry><entry></entry><entry>Y</entry><entry>C</entry>
 138                       <entry>Y</entry><entry></entry><entry>Y</entry>
 139                     </row>
 140                   </tbody>
 141                 </tgroup>
 142                 </informaltable>
 143               </para>
 144           </formalpara>
 145         </example>
 146       </refsect1>
 147     </refentry>
 148
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