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---
r: 330986
b: refs/heads/master
c: 8ab0238
h: refs/heads/master
v: v3
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Shaik Ameer Basha authored and Mauro Carvalho Chehab committed Sep 15, 2012
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: aa15f47714e0e98ae78c1516c2fc989fd375fe3b
refs/heads/master: 8ab023812b2b5e81bb1876a925541bceaf62538a
154 changes: 154 additions & 0 deletions trunk/Documentation/DocBook/media/v4l/pixfmt-yvu420m.xml
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<refentry id="V4L2-PIX-FMT-YVU420M">
<refmeta>
<refentrytitle>V4L2_PIX_FMT_YVU420M ('YM21')</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname> <constant>V4L2_PIX_FMT_YVU420M</constant></refname>
<refpurpose>Variation of <constant>V4L2_PIX_FMT_YVU420</constant>
with planes non contiguous in memory. </refpurpose>
</refnamediv>

<refsect1>
<title>Description</title>

<para>This is a multi-planar format, as opposed to a packed format.
The three components are separated into three sub-images or planes.

The Y plane is first. The Y plane has one byte per pixel. The Cr data
constitutes the second plane which is half the width and half
the height of the Y plane (and of the image). Each Cr belongs to four
pixels, a two-by-two square of the image. For example,
Cr<subscript>0</subscript> belongs to Y'<subscript>00</subscript>,
Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and
Y'<subscript>11</subscript>. The Cb data, just like the Cr plane, constitutes
the third plane. </para>

<para>If the Y plane has pad bytes after each row, then the Cr
and Cb planes have half as many pad bytes after their rows. In other
words, two Cx rows (including padding) is exactly as long as one Y row
(including padding).</para>

<para><constant>V4L2_PIX_FMT_YVU420M</constant> is intended to be
used only in drivers and applications that support the multi-planar API,
described in <xref linkend="planar-apis"/>. </para>

<example>
<title><constant>V4L2_PIX_FMT_YVU420M</constant> 4 &times; 4
pixel image</title>

<formalpara>
<title>Byte Order.</title>
<para>Each cell is one byte.
<informaltable frame="none">
<tgroup cols="5" align="center">
<colspec align="left" colwidth="2*" />
<tbody valign="top">
<row>
<entry>start0&nbsp;+&nbsp;0:</entry>
<entry>Y'<subscript>00</subscript></entry>
<entry>Y'<subscript>01</subscript></entry>
<entry>Y'<subscript>02</subscript></entry>
<entry>Y'<subscript>03</subscript></entry>
</row>
<row>
<entry>start0&nbsp;+&nbsp;4:</entry>
<entry>Y'<subscript>10</subscript></entry>
<entry>Y'<subscript>11</subscript></entry>
<entry>Y'<subscript>12</subscript></entry>
<entry>Y'<subscript>13</subscript></entry>
</row>
<row>
<entry>start0&nbsp;+&nbsp;8:</entry>
<entry>Y'<subscript>20</subscript></entry>
<entry>Y'<subscript>21</subscript></entry>
<entry>Y'<subscript>22</subscript></entry>
<entry>Y'<subscript>23</subscript></entry>
</row>
<row>
<entry>start0&nbsp;+&nbsp;12:</entry>
<entry>Y'<subscript>30</subscript></entry>
<entry>Y'<subscript>31</subscript></entry>
<entry>Y'<subscript>32</subscript></entry>
<entry>Y'<subscript>33</subscript></entry>
</row>
<row><entry></entry></row>
<row>
<entry>start1&nbsp;+&nbsp;0:</entry>
<entry>Cr<subscript>00</subscript></entry>
<entry>Cr<subscript>01</subscript></entry>
</row>
<row>
<entry>start1&nbsp;+&nbsp;2:</entry>
<entry>Cr<subscript>10</subscript></entry>
<entry>Cr<subscript>11</subscript></entry>
</row>
<row><entry></entry></row>
<row>
<entry>start2&nbsp;+&nbsp;0:</entry>
<entry>Cb<subscript>00</subscript></entry>
<entry>Cb<subscript>01</subscript></entry>
</row>
<row>
<entry>start2&nbsp;+&nbsp;2:</entry>
<entry>Cb<subscript>10</subscript></entry>
<entry>Cb<subscript>11</subscript></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</formalpara>

<formalpara>
<title>Color Sample Location.</title>
<para>
<informaltable frame="none">
<tgroup cols="7" align="center">
<tbody valign="top">
<row>
<entry></entry>
<entry>0</entry><entry></entry><entry>1</entry><entry></entry>
<entry>2</entry><entry></entry><entry>3</entry>
</row>
<row>
<entry>0</entry>
<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
<entry>Y</entry><entry></entry><entry>Y</entry>
</row>
<row>
<entry></entry>
<entry></entry><entry>C</entry><entry></entry><entry></entry>
<entry></entry><entry>C</entry><entry></entry>
</row>
<row>
<entry>1</entry>
<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
<entry>Y</entry><entry></entry><entry>Y</entry>
</row>
<row>
<entry></entry>
</row>
<row>
<entry>2</entry>
<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
<entry>Y</entry><entry></entry><entry>Y</entry>
</row>
<row>
<entry></entry>
<entry></entry><entry>C</entry><entry></entry><entry></entry>
<entry></entry><entry>C</entry><entry></entry>
</row>
<row>
<entry>3</entry>
<entry>Y</entry><entry></entry><entry>Y</entry><entry></entry>
<entry>Y</entry><entry></entry><entry>Y</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</formalpara>
</example>
</refsect1>
</refentry>
1 change: 1 addition & 0 deletions trunk/Documentation/DocBook/media/v4l/pixfmt.xml
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Expand Up @@ -708,6 +708,7 @@ information.</para>
&sub-y41p;
&sub-yuv420;
&sub-yuv420m;
&sub-yvu420m;
&sub-yuv410;
&sub-yuv422p;
&sub-yuv411p;
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1 change: 1 addition & 0 deletions trunk/include/linux/videodev2.h
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Expand Up @@ -368,6 +368,7 @@ struct v4l2_pix_format {

/* three non contiguous planes - Y, Cb, Cr */
#define V4L2_PIX_FMT_YUV420M v4l2_fourcc('Y', 'M', '1', '2') /* 12 YUV420 planar */
#define V4L2_PIX_FMT_YVU420M v4l2_fourcc('Y', 'M', '2', '1') /* 12 YVU420 planar */

/* Bayer formats - see http://www.siliconimaging.com/RGB%20Bayer.htm */
#define V4L2_PIX_FMT_SBGGR8 v4l2_fourcc('B', 'A', '8', '1') /* 8 BGBG.. GRGR.. */
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