--- /dev/null
+ <refentry>
+ <refmeta>
+ <refentrytitle>V4L2_PIX_FMT_NV12M ('NM12'), V4L2_PIX_FMT_NV21M ('NM21'), V4L2_PIX_FMT_NV12MT_16X16</refentrytitle>
+ &manvol;
+ </refmeta>
+ <refnamediv>
+ <refname id="V4L2-PIX-FMT-NV12M"><constant>V4L2_PIX_FMT_NV12M</constant></refname>
+ <refname id="V4L2-PIX-FMT-NV21M"><constant>V4L2_PIX_FMT_NV21M</constant></refname>
+ <refname id="V4L2-PIX-FMT-NV12MT-16X16"><constant>V4L2_PIX_FMT_NV12MT_16X16</constant></refname>
+ <refpurpose>Variation of <constant>V4L2_PIX_FMT_NV12</constant> and <constant>V4L2_PIX_FMT_NV21</constant> with planes
+ non contiguous in memory. </refpurpose>
+ </refnamediv>
+ <refsect1>
+ <title>Description</title>
+
+ <para>This is a multi-planar, two-plane version of the YUV 4:2:0 format.
+The three components are separated into two sub-images or planes.
+<constant>V4L2_PIX_FMT_NV12M</constant> differs from <constant>V4L2_PIX_FMT_NV12
+</constant> in that the two planes are non-contiguous in memory, i.e. the chroma
+plane do not necessarily immediately follows the luma plane.
+The luminance data occupies the first plane. The Y plane has one byte per pixel.
+In the second plane there is a chrominance data with alternating chroma samples.
+The CbCr plane is the same width, in bytes, as the Y plane (and of the image),
+but is half as tall in pixels. Each CbCr pair belongs to four pixels. For example,
+Cb<subscript>0</subscript>/Cr<subscript>0</subscript> belongs to
+Y'<subscript>00</subscript>, Y'<subscript>01</subscript>,
+Y'<subscript>10</subscript>, Y'<subscript>11</subscript>.
+<constant>V4L2_PIX_FMT_NV12MT_16X16</constant> is the tiled version of
+<constant>V4L2_PIX_FMT_NV12M</constant> with 16x16 macroblock tiles. Here pixels
+are arranged in 16x16 2D tiles and tiles are arranged in linear order in memory.
+<constant>V4L2_PIX_FMT_NV21M</constant> is the same as <constant>V4L2_PIX_FMT_NV12M</constant>
+except the Cb and Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para>
+
+ <para><constant>V4L2_PIX_FMT_NV12M</constant> is intended to be
+used only in drivers and applications that support the multi-planar API,
+described in <xref linkend="planar-apis"/>. </para>
+
+ <para>If the Y plane has pad bytes after each row, then the
+CbCr plane has as many pad bytes after its rows.</para>
+
+ <example>
+ <title><constant>V4L2_PIX_FMT_NV12M</constant> 4 × 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 + 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 + 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 + 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 + 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 + 0:</entry>
+ <entry>Cb<subscript>00</subscript></entry>
+ <entry>Cr<subscript>00</subscript></entry>
+ <entry>Cb<subscript>01</subscript></entry>
+ <entry>Cr<subscript>01</subscript></entry>
+ </row>
+ <row>
+ <entry>start1 + 4:</entry>
+ <entry>Cb<subscript>10</subscript></entry>
+ <entry>Cr<subscript>10</subscript></entry>
+ <entry>Cb<subscript>11</subscript></entry>
+ <entry>Cr<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>
Code Review / kvmfornfv.git / blobdiff