Documentation/DocBook/v4l/pixfmt-nv16.xml

   1     <refentry>
   2       <refmeta>
   3         <refentrytitle>V4L2_PIX_FMT_NV16 ('NV16'), V4L2_PIX_FMT_NV61 ('NV61')</refentrytitle>
   4         &manvol;
   5       </refmeta>
   6       <refnamediv>
   7         <refname id="V4L2-PIX-FMT-NV16"><constant>V4L2_PIX_FMT_NV16</constant></refname>
   8         <refname id="V4L2-PIX-FMT-NV61"><constant>V4L2_PIX_FMT_NV61</constant></refname>
   9         <refpurpose>Formats with &frac12; horizontal
  10 chroma resolution, also known as YUV 4:2:2. One luminance and one
  11 chrominance plane with alternating chroma samples as opposed to
  12 <constant>V4L2_PIX_FMT_YVU420</constant></refpurpose>
  13       </refnamediv>
  14       <refsect1>
  15         <title>Description</title>
  16
  17         <para>These are two-plane versions of the YUV 4:2:2 format.
  18 The three components are separated into two sub-images or planes. The
  19 Y plane is first. The Y plane has one byte per pixel. For
  20 <constant>V4L2_PIX_FMT_NV16</constant>, a combined CbCr plane
  21 immediately follows the Y plane in memory.  The CbCr plane is the same
  22 width and height, in bytes, as the Y plane (and of the image).
  23 Each CbCr pair belongs to two pixels. For example,
  24 Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to
  25 Y'<subscript>00</subscript>, Y'<subscript>01</subscript>.
  26 <constant>V4L2_PIX_FMT_NV61</constant> is the same except the Cb and
  27 Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para>
  28
  29         <para>If the Y plane has pad bytes after each row, then the
  30 CbCr plane has as many pad bytes after its rows.</para>
  31
  32         <example>
  33           <title><constant>V4L2_PIX_FMT_NV16</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                       <entry>Cr<subscript>00</subscript></entry>
  75                       <entry>Cb<subscript>01</subscript></entry>
  76                       <entry>Cr<subscript>01</subscript></entry>
  77                     </row>
  78                     <row>
  79                       <entry>start&nbsp;+&nbsp;20:</entry>
  80                       <entry>Cb<subscript>10</subscript></entry>
  81                       <entry>Cr<subscript>10</subscript></entry>
  82                       <entry>Cb<subscript>11</subscript></entry>
  83                       <entry>Cr<subscript>11</subscript></entry>
  84                     </row>
  85                     <row>
  86                       <entry>start&nbsp;+&nbsp;24:</entry>
  87                       <entry>Cb<subscript>20</subscript></entry>
  88                       <entry>Cr<subscript>20</subscript></entry>
  89                       <entry>Cb<subscript>21</subscript></entry>
  90                       <entry>Cr<subscript>21</subscript></entry>
  91                     </row>
  92                     <row>
  93                       <entry>start&nbsp;+&nbsp;28:</entry>
  94                       <entry>Cb<subscript>30</subscript></entry>
  95                       <entry>Cr<subscript>30</subscript></entry>
  96                       <entry>Cb<subscript>31</subscript></entry>
  97                       <entry>Cr<subscript>31</subscript></entry>
  98                     </row>
  99                   </tbody>
 100                 </tgroup>
 101                 </informaltable>
 102               </para>
 103           </formalpara>
 104
 105           <formalpara>
 106             <title>Color Sample Location.</title>
 107             <para>
 108                 <informaltable frame="none">
 109                 <tgroup cols="7" align="center">
 110                   <tbody valign="top">
 111                     <row>
 112                       <entry></entry>
 113                       <entry>0</entry><entry></entry><entry>1</entry><entry></entry>
 114                       <entry>2</entry><entry></entry><entry>3</entry>
 115                     </row>
 116                     <row>
 117                       <entry>0</entry>
 118                       <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
 119                       <entry>Y</entry><entry></entry><entry>Y</entry>
 120                     </row>
 121                     <row>
 122                       <entry></entry>
 123                       <entry></entry><entry>C</entry><entry></entry><entry></entry>
 124                       <entry></entry><entry>C</entry><entry></entry>
 125                     </row>
 126                     <row>
 127                       <entry>1</entry>
 128                       <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
 129                       <entry>Y</entry><entry></entry><entry>Y</entry>
 130                     </row>
 131                     <row>
 132                       <entry></entry>
 133                       <entry></entry><entry>C</entry><entry></entry><entry></entry>
 134                       <entry></entry><entry>C</entry><entry></entry>
 135                     </row>
 136                     <row>
 137                       <entry></entry>
 138                     </row>
 139                     <row>
 140                       <entry>2</entry>
 141                       <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
 142                       <entry>Y</entry><entry></entry><entry>Y</entry>
 143                     </row>
 144                     <row>
 145                       <entry></entry>
 146                       <entry></entry><entry>C</entry><entry></entry><entry></entry>
 147                       <entry></entry><entry>C</entry><entry></entry>
 148                     </row>
 149                     <row>
 150                       <entry>3</entry>
 151                       <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
 152                       <entry>Y</entry><entry></entry><entry>Y</entry>
 153                     </row>
 154                     <row>
 155                       <entry></entry>
 156                       <entry></entry><entry>C</entry><entry></entry><entry></entry>
 157                       <entry></entry><entry>C</entry><entry></entry>
 158                     </row>
 159                   </tbody>
 160                 </tgroup>
 161                 </informaltable>
 162               </para>
 163           </formalpara>
 164         </example>
 165       </refsect1>
 166     </refentry>
 167
 168   <!--
 169 Local Variables:
 170 mode: sgml
 171 sgml-parent-document: "pixfmt.sgml"
 172 indent-tabs-mode: nil
 173 End:
 174   -->