--- /dev/null
+<section id="v4l2-selections-common">
+
+ <title>Common selection definitions</title>
+
+ <para>While the <link linkend="selection-api">V4L2 selection
+ API</link> and <link linkend="v4l2-subdev-selections">V4L2 subdev
+ selection APIs</link> are very similar, there's one fundamental
+ difference between the two. On sub-device API, the selection
+ rectangle refers to the media bus format, and is bound to a
+ sub-device's pad. On the V4L2 interface the selection rectangles
+ refer to the in-memory pixel format.</para>
+
+ <para>This section defines the common definitions of the
+ selection interfaces on the two APIs.</para>
+
+ <section id="v4l2-selection-targets">
+
+ <title>Selection targets</title>
+
+ <para>The precise meaning of the selection targets may be
+ dependent on which of the two interfaces they are used.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-selection-targets-table">
+ <title>Selection target definitions</title>
+ <tgroup cols="5">
+ <colspec colname="c1" />
+ <colspec colname="c2" />
+ <colspec colname="c3" />
+ <colspec colname="c4" />
+ <colspec colname="c5" />
+ &cs-def;
+ <thead>
+ <row rowsep="1">
+ <entry align="left">Target name</entry>
+ <entry align="left">id</entry>
+ <entry align="left">Definition</entry>
+ <entry align="left">Valid for V4L2</entry>
+ <entry align="left">Valid for V4L2 subdev</entry>
+ </row>
+ </thead>
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_SEL_TGT_CROP</constant></entry>
+ <entry>0x0000</entry>
+ <entry>Crop rectangle. Defines the cropped area.</entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_CROP_DEFAULT</constant></entry>
+ <entry>0x0001</entry>
+ <entry>Suggested cropping rectangle that covers the "whole picture".</entry>
+ <entry>Yes</entry>
+ <entry>No</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_CROP_BOUNDS</constant></entry>
+ <entry>0x0002</entry>
+ <entry>Bounds of the crop rectangle. All valid crop
+ rectangles fit inside the crop bounds rectangle.
+ </entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_NATIVE_SIZE</constant></entry>
+ <entry>0x0003</entry>
+ <entry>The native size of the device, e.g. a sensor's
+ pixel array. <structfield>left</structfield> and
+ <structfield>top</structfield> fields are zero for this
+ target. Setting the native size will generally only make
+ sense for memory to memory devices where the software can
+ create a canvas of a given size in which for example a
+ video frame can be composed. In that case
+ V4L2_SEL_TGT_NATIVE_SIZE can be used to configure the size
+ of that canvas.
+ </entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_COMPOSE</constant></entry>
+ <entry>0x0100</entry>
+ <entry>Compose rectangle. Used to configure scaling
+ and composition.</entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_COMPOSE_DEFAULT</constant></entry>
+ <entry>0x0101</entry>
+ <entry>Suggested composition rectangle that covers the "whole picture".</entry>
+ <entry>Yes</entry>
+ <entry>No</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_COMPOSE_BOUNDS</constant></entry>
+ <entry>0x0102</entry>
+ <entry>Bounds of the compose rectangle. All valid compose
+ rectangles fit inside the compose bounds rectangle.</entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_TGT_COMPOSE_PADDED</constant></entry>
+ <entry>0x0103</entry>
+ <entry>The active area and all padding pixels that are inserted or
+ modified by hardware.</entry>
+ <entry>Yes</entry>
+ <entry>No</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </section>
+
+ <section id="v4l2-selection-flags">
+
+ <title>Selection flags</title>
+
+ <table pgwide="1" frame="none" id="v4l2-selection-flags-table">
+ <title>Selection flag definitions</title>
+ <tgroup cols="5">
+ <colspec colname="c1" />
+ <colspec colname="c2" />
+ <colspec colname="c3" />
+ <colspec colname="c4" />
+ <colspec colname="c5" />
+ &cs-def;
+ <thead>
+ <row rowsep="1">
+ <entry align="left">Flag name</entry>
+ <entry align="left">id</entry>
+ <entry align="left">Definition</entry>
+ <entry align="left">Valid for V4L2</entry>
+ <entry align="left">Valid for V4L2 subdev</entry>
+ </row>
+ </thead>
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_SEL_FLAG_GE</constant></entry>
+ <entry>(1 << 0)</entry>
+ <entry>Suggest the driver it should choose greater or
+ equal rectangle (in size) than was requested. Albeit the
+ driver may choose a lesser size, it will only do so due to
+ hardware limitations. Without this flag (and
+ <constant>V4L2_SEL_FLAG_LE</constant>) the
+ behaviour is to choose the closest possible
+ rectangle.</entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_FLAG_LE</constant></entry>
+ <entry>(1 << 1)</entry>
+ <entry>Suggest the driver it
+ should choose lesser or equal rectangle (in size) than was
+ requested. Albeit the driver may choose a greater size, it
+ will only do so due to hardware limitations.</entry>
+ <entry>Yes</entry>
+ <entry>Yes</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SEL_FLAG_KEEP_CONFIG</constant></entry>
+ <entry>(1 << 2)</entry>
+ <entry>The configuration must not be propagated to any
+ further processing steps. If this flag is not given, the
+ configuration is propagated inside the subdevice to all
+ further processing steps.</entry>
+ <entry>No</entry>
+ <entry>Yes</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </section>
+
+</section>
Code Review / kvmfornfv.git / blobdiff