1 <refentry id="V4L2-PIX-FMT-M420"> 2 <refmeta> 3 <refentrytitle>V4L2_PIX_FMT_M420 ('M420')</refentrytitle> 4 &manvol; 5 </refmeta> 6 <refnamediv> 7 <refname><constant>V4L2_PIX_FMT_M420</constant></refname> 8 <refpurpose>Format with ½ horizontal and vertical chroma 9 resolution, also known as YUV 4:2:0. Hybrid plane line-interleaved 10 layout.</refpurpose> 11 </refnamediv> 12 <refsect1> 13 <title>Description</title> 14 15 <para>M420 is a YUV format with ½ horizontal and vertical chroma 16 subsampling (YUV 4:2:0). Pixels are organized as interleaved luma and 17 chroma planes. Two lines of luma data are followed by one line of chroma 18 data.</para> 19 <para>The luma plane has one byte per pixel. The chroma plane contains 20 interleaved CbCr pixels subsampled by ½ in the horizontal and 21 vertical directions. Each CbCr pair belongs to four pixels. For example, 22Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to 23Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, 24Y'<subscript>10</subscript>, Y'<subscript>11</subscript>.</para> 25 26 <para>All line lengths are identical: if the Y lines include pad bytes 27 so do the CbCr lines.</para> 28 29 <example> 30 <title><constant>V4L2_PIX_FMT_M420</constant> 4 × 4 31pixel image</title> 32 33 <formalpara> 34 <title>Byte Order.</title> 35 <para>Each cell is one byte. 36 <informaltable frame="none"> 37 <tgroup cols="5" align="center"> 38 <colspec align="left" colwidth="2*" /> 39 <tbody valign="top"> 40 <row> 41 <entry>start + 0:</entry> 42 <entry>Y'<subscript>00</subscript></entry> 43 <entry>Y'<subscript>01</subscript></entry> 44 <entry>Y'<subscript>02</subscript></entry> 45 <entry>Y'<subscript>03</subscript></entry> 46 </row> 47 <row> 48 <entry>start + 4:</entry> 49 <entry>Y'<subscript>10</subscript></entry> 50 <entry>Y'<subscript>11</subscript></entry> 51 <entry>Y'<subscript>12</subscript></entry> 52 <entry>Y'<subscript>13</subscript></entry> 53 </row> 54 <row> 55 <entry>start + 8:</entry> 56 <entry>Cb<subscript>00</subscript></entry> 57 <entry>Cr<subscript>00</subscript></entry> 58 <entry>Cb<subscript>01</subscript></entry> 59 <entry>Cr<subscript>01</subscript></entry> 60 </row> 61 <row> 62 <entry>start + 16:</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>start + 20:</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> 76 <entry>start + 24:</entry> 77 <entry>Cb<subscript>10</subscript></entry> 78 <entry>Cr<subscript>10</subscript></entry> 79 <entry>Cb<subscript>11</subscript></entry> 80 <entry>Cr<subscript>11</subscript></entry> 81 </row> 82 </tbody> 83 </tgroup> 84 </informaltable> 85 </para> 86 </formalpara> 87 88 <formalpara> 89 <title>Color Sample Location.</title> 90 <para> 91 <informaltable frame="none"> 92 <tgroup cols="7" align="center"> 93 <tbody valign="top"> 94 <row> 95 <entry></entry> 96 <entry>0</entry><entry></entry><entry>1</entry><entry></entry> 97 <entry>2</entry><entry></entry><entry>3</entry> 98 </row> 99 <row> 100 <entry>0</entry> 101 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> 102 <entry>Y</entry><entry></entry><entry>Y</entry> 103 </row> 104 <row> 105 <entry></entry> 106 <entry></entry><entry>C</entry><entry></entry><entry></entry> 107 <entry></entry><entry>C</entry><entry></entry> 108 </row> 109 <row> 110 <entry>1</entry> 111 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> 112 <entry>Y</entry><entry></entry><entry>Y</entry> 113 </row> 114 <row> 115 <entry></entry> 116 </row> 117 <row> 118 <entry>2</entry> 119 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> 120 <entry>Y</entry><entry></entry><entry>Y</entry> 121 </row> 122 <row> 123 <entry></entry> 124 <entry></entry><entry>C</entry><entry></entry><entry></entry> 125 <entry></entry><entry>C</entry><entry></entry> 126 </row> 127 <row> 128 <entry>3</entry> 129 <entry>Y</entry><entry></entry><entry>Y</entry><entry></entry> 130 <entry>Y</entry><entry></entry><entry>Y</entry> 131 </row> 132 </tbody> 133 </tgroup> 134 </informaltable> 135 </para> 136 </formalpara> 137 </example> 138 </refsect1> 139 </refentry> 140