aboutsummaryrefslogtreecommitdiff
path: root/Documentation/DocBook/media/v4l/pixfmt-nv12.xml
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/DocBook/media/v4l/pixfmt-nv12.xml')
-rw-r--r--Documentation/DocBook/media/v4l/pixfmt-nv12.xml143
1 files changed, 143 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv12.xml b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml
new file mode 100644
index 00000000..84dd4fd7
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/pixfmt-nv12.xml
@@ -0,0 +1,143 @@
+ <refentry>
+ <refmeta>
+ <refentrytitle>V4L2_PIX_FMT_NV12 ('NV12'), V4L2_PIX_FMT_NV21 ('NV21')</refentrytitle>
+ &manvol;
+ </refmeta>
+ <refnamediv>
+ <refname id="V4L2-PIX-FMT-NV12"><constant>V4L2_PIX_FMT_NV12</constant></refname>
+ <refname id="V4L2-PIX-FMT-NV21"><constant>V4L2_PIX_FMT_NV21</constant></refname>
+ <refpurpose>Formats with &frac12; horizontal and vertical
+chroma resolution, also known as YUV 4:2:0. One luminance and one
+chrominance plane with alternating chroma samples as opposed to
+<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose>
+ </refnamediv>
+ <refsect1>
+ <title>Description</title>
+
+ <para>These are two-plane versions of the YUV 4:2:0 format.
+The three components are separated into two sub-images or planes. The
+Y plane is first. The Y plane has one byte per pixel. For
+<constant>V4L2_PIX_FMT_NV12</constant>, a combined CbCr plane
+immediately follows the Y plane in memory. 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_NV21</constant> is the same except the Cb and
+Cr bytes are swapped, the CrCb plane starts with a Cr byte.</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_NV12</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>start&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>start&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>start&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>start&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>start&nbsp;+&nbsp;16:</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>start&nbsp;+&nbsp;20:</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>