1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API"><link rel="up" href="yuv-formats.html" title="YUV Formats"><link rel="prev" href="V4L2-PIX-FMT-YUV411P.html" title="V4L2_PIX_FMT_YUV411P ('411P')"><link rel="next" href="re31.html" title="V4L2_PIX_FMT_NV12M ('NM12'), V4L2_PIX_FMT_NV21M ('NM21'), V4L2_PIX_FMT_NV12MT_16X16"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="V4L2-PIX-FMT-YUV411P.html">Prev</a> </td><th width="60%" align="center">YUV Formats</th><td width="20%" align="right"> <a accesskey="n" href="re31.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="idp1102451140"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p><code class="constant">V4L2_PIX_FMT_NV12</code>, <code class="constant">V4L2_PIX_FMT_NV21</code> — Formats with ½ horizontal and vertical 2chroma resolution, also known as YUV 4:2:0. One luminance and one 3chrominance plane with alternating chroma samples as opposed to 4<code class="constant">V4L2_PIX_FMT_YVU420</code></p></div><div class="refsect1"><a name="idp1102449196"></a><h2>Description</h2><p>These are two-plane versions of the YUV 4:2:0 format. 5The three components are separated into two sub-images or planes. The 6Y plane is first. The Y plane has one byte per pixel. For 7<code class="constant">V4L2_PIX_FMT_NV12</code>, a combined CbCr plane 8immediately follows the Y plane in memory. The CbCr plane is the same 9width, in bytes, as the Y plane (and of the image), but is half as 10tall in pixels. Each CbCr pair belongs to four pixels. For example, 11Cb<sub>0</sub>/Cr<sub>0</sub> belongs to 12Y'<sub>00</sub>, Y'<sub>01</sub>, 13Y'<sub>10</sub>, Y'<sub>11</sub>. 14<code class="constant">V4L2_PIX_FMT_NV21</code> is the same except the Cb and 15Cr bytes are swapped, the CrCb plane starts with a Cr byte.</p><p>If the Y plane has pad bytes after each row, then the 16CbCr plane has as many pad bytes after its rows.</p><div class="example"><a name="idp1102454540"></a><p class="title"><b>Example 2.27. <code class="constant">V4L2_PIX_FMT_NV12</code> 4 × 4 17pixel image</b></p><div class="example-contents"><p><b>Byte Order. </b>Each cell is one byte. 18 </p><div class="informaltable"><table border="0"><colgroup><col align="left"><col><col><col><col></colgroup><tbody valign="top"><tr><td align="left" valign="top">start + 0:</td><td align="center" valign="top">Y'<sub>00</sub></td><td align="center" valign="top">Y'<sub>01</sub></td><td align="center" valign="top">Y'<sub>02</sub></td><td align="center" valign="top">Y'<sub>03</sub></td></tr><tr><td align="left" valign="top">start + 4:</td><td align="center" valign="top">Y'<sub>10</sub></td><td align="center" valign="top">Y'<sub>11</sub></td><td align="center" valign="top">Y'<sub>12</sub></td><td align="center" valign="top">Y'<sub>13</sub></td></tr><tr><td align="left" valign="top">start + 8:</td><td align="center" valign="top">Y'<sub>20</sub></td><td align="center" valign="top">Y'<sub>21</sub></td><td align="center" valign="top">Y'<sub>22</sub></td><td align="center" valign="top">Y'<sub>23</sub></td></tr><tr><td align="left" valign="top">start + 12:</td><td align="center" valign="top">Y'<sub>30</sub></td><td align="center" valign="top">Y'<sub>31</sub></td><td align="center" valign="top">Y'<sub>32</sub></td><td align="center" valign="top">Y'<sub>33</sub></td></tr><tr><td align="left" valign="top">start + 16:</td><td align="center" valign="top">Cb<sub>00</sub></td><td align="center" valign="top">Cr<sub>00</sub></td><td align="center" valign="top">Cb<sub>01</sub></td><td align="center" valign="top">Cr<sub>01</sub></td></tr><tr><td align="left" valign="top">start + 20:</td><td align="center" valign="top">Cb<sub>10</sub></td><td align="center" valign="top">Cr<sub>10</sub></td><td align="center" valign="top">Cb<sub>11</sub></td><td align="center" valign="top">Cr<sub>11</sub></td></tr></tbody></table></div><p> 19 </p><p><b>Color Sample Location. </b> 20 </p><div class="informaltable"><table border="0"><colgroup><col><col><col><col><col><col><col></colgroup><tbody valign="top"><tr><td align="center" valign="top"> </td><td align="center" valign="top">0</td><td align="center" valign="top"> </td><td align="center" valign="top">1</td><td align="center" valign="top"> </td><td align="center" valign="top">2</td><td align="center" valign="top"> </td><td align="center" valign="top">3</td></tr><tr><td align="center" valign="top">0</td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td></tr><tr><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top">C</td><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top">C</td><td align="center" valign="top"> </td></tr><tr><td align="center" valign="top">1</td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td></tr><tr><td align="center" valign="top"> </td><td class="auto-generated"> </td><td class="auto-generated"> </td><td class="auto-generated"> </td><td class="auto-generated"> </td><td class="auto-generated"> </td><td class="auto-generated"> </td></tr><tr><td align="center" valign="top">2</td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td></tr><tr><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top">C</td><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top"> </td><td align="center" valign="top">C</td><td align="center" valign="top"> </td></tr><tr><td align="center" valign="top">3</td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td><td align="center" valign="top"> </td><td align="center" valign="top">Y</td></tr></tbody></table></div><p> 21 </p></div></div><br class="example-break"></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="V4L2-PIX-FMT-YUV411P.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="yuv-formats.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re31.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">V4L2_PIX_FMT_YUV411P ('411P') </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> V4L2_PIX_FMT_NV12M ('NM12'), V4L2_PIX_FMT_NV21M ('NM21'), V4L2_PIX_FMT_NV12MT_16X16</td></tr></table></div></body></html> 22