Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxx>
---
Documentation/DocBook/media/v4l/dev-subdev.xml | 95 +++++++--
Documentation/DocBook/media/v4l/v4l2.xml | 1 +
.../media/v4l/vidioc-subdev-g-selection.xml | 226 ++++++++++++++++++++
3 files changed, 302 insertions(+), 20 deletions(-)
create mode 100644 Documentation/DocBook/media/v4l/vidioc-subdev-g-selection.xml
diff --git a/Documentation/DocBook/media/v4l/dev-subdev.xml b/Documentation/DocBook/media/v4l/dev-subdev.xml
index 0916a73..722db60 100644
--- a/Documentation/DocBook/media/v4l/dev-subdev.xml
+++ b/Documentation/DocBook/media/v4l/dev-subdev.xml
@@ -77,7 +77,7 @@
format, frame width and frame height.</para></note>
<para>Image formats are typically negotiated on video capture and output
- devices using the <link linkend="crop">cropping and scaling</link> ioctls.
+ devices using the format and <link linkend="selection">selection</link> ioctls.
The driver is responsible for configuring every block in the video pipeline
according to the requested format at the pipeline input and/or
output.</para>
@@ -276,11 +276,11 @@
</section>
<section>
- <title>Cropping and scaling</title>
+ <title>Selections: cropping, scaling and composition</title>
<para>Many sub-devices support cropping frames on their input or output
pads (or possible even on both). Cropping is used to select the area of
- interest in an image, typically on a video sensor or video decoder. It can
+ interest in an image, typically on an image sensor or a video decoder. It can
also be used as part of digital zoom implementations to select the area of
the image that will be scaled up.</para>
@@ -288,26 +288,81 @@
&v4l2-rect; by the coordinates of the top left corner and the rectangle
size. Both the coordinates and sizes are expressed in pixels.</para>
- <para>The crop rectangle is retrieved and set using the
- &VIDIOC-SUBDEV-G-CROP; and &VIDIOC-SUBDEV-S-CROP; ioctls. Like for pad
- formats, drivers store try and active crop rectangles. The format
- negotiation mechanism applies to crop settings as well.</para>
-
- <para>On input pads, cropping is applied relatively to the current pad
- format. The pad format represents the image size as received by the
- sub-device from the previous block in the pipeline, and the crop rectangle
- represents the sub-image that will be transmitted further inside the
- sub-device for processing. The crop rectangle be entirely containted
- inside the input image size.</para>
-
- <para>Input crop rectangle are reset to their default value when the input
- image format is modified. Drivers should use the input image size as the
- crop rectangle default value, but hardware requirements may prevent this.
- </para>
+ <para>Scaling operation changes the size of the image by scaling
+ it to new dimensions. Some sub-devices support it. The scaled
+ size (width and height) is represented by &v4l2-rect;. In the
+ case of scaling, top and left will always be zero. Scaling is
+ configured using &sub-subdev-g-selection; and
+ <constant>V4L2_SUBDEV_SEL_COMPOSE_ACTIVE</constant> selection
+ target on the sink pad of the subdev. The scaling is performed
+ related to the width and height of the crop rectangle on the
+ subdev's sink pad.</para>
+
+ <para>As for pad formats, drivers store try and active
+ rectangles for the selection targets of ACTIVE type <xref
+ linkend="v4l2-subdev-selection-targets">.</xref></para>
+
+ <para>On sink pads, cropping is applied relatively to the
+ current pad format. The pad format represents the image size as
+ received by the sub-device from the previous block in the
+ pipeline, and the crop rectangle represents the sub-image that
+ will be transmitted further inside the sub-device for
+ processing.</para>
+
+ <para>On source pads, cropping is similar to sink pads, with the
+ exception that the source size from which the cropping is
+ performed, is the COMPOSE rectangle on the sink pad. In both
+ sink and source pads, the crop rectangle must be entirely
+ containted inside the source image size for the crop
+ operation.</para>
+
+ <para>The drivers should always use the closest possible
+ rectangle the user requests on all selection targets, unless
+ specificly told otherwise<xref
+ linkend="v4l2-subdev-selection-flags">.</xref></para>
+ </section>
+
+ <section>
+ <title>Order of configuration and format propagation</title>
+
+ <para>The order of image processing steps will always be from
+ the sink pad towards the source pad. This is also reflected in
+ the order in which the configuration must be performed by the
+ user. The format is propagated within the subdev along the later
+ processing steps. For example, setting the sink pad format
+ causes all the selection rectangles and the source pad format to
+ be set to sink pad format --- if allowed by the hardware, and if
+ not, then closest possible. The coordinates to a step always
+ refer to the active size of the previous step.</para>
+
+ <orderedlist>
+ <listitem>Sink pad format. The user configures the sink pad
+ format. This format defines the parameters of the image the
+ entity receives through the pad for further processing.</listitem>
- <para>Cropping behaviour on output pads is not defined.</para>
+ <listitem>Sink pad active crop selection. The sink pad crop
+ defines the performed to the sink pad format.</listitem>
+ <listitem>Sink pad active compose selection. The sink pad compose
+ rectangle defines the scaling ratio compared to the size of
+ the sink pad crop rectangle.</listitem>
+
+ <listitem>Source pad active crop selection. Crop on the source
+ pad defines crop performed to the image scaled according to
+ the sink pad compose rectangle.</listitem>
+
+ <listitem>Source pad active compose selection. The source pad
+ compose defines the size and location of the compose
+ rectangle.</listitem>
+
+ <listitem>Source pad format. The source pad format defines the
+ output pixel format of the subdev, as well as the other
+ parameters with the exception of the image width and
+ height.</listitem>
+
+ </orderedlist>
</section>
+
</section>
&sub-subdev-formats;
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index affe1ba..3ff11a6 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -529,6 +529,7 @@ and discussions on the V4L mailing list.</revremark>
&sub-subdev-g-crop;
&sub-subdev-g-fmt;
&sub-subdev-g-frame-interval;
+ &sub-subdev-g-selection;
&sub-subscribe-event;
<!-- End of ioctls. -->
&sub-mmap;
diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-selection.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-selection.xml
new file mode 100644
index 0000000..5fbcd65
--- /dev/null
+++ b/Documentation/DocBook/media/v4l/vidioc-subdev-g-selection.xml
@@ -0,0 +1,226 @@
+<refentry id="vidioc-subdev-g-selection">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_SUBDEV_G_SELECTION</refname>
+ <refname>VIDIOC_SUBDEV_S_SELECTION</refname>
+ <refpurpose>Get or set selection rectangles on a subdev pad</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>int <function>ioctl</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>int <parameter>request</parameter></paramdef>
+ <paramdef>struct v4l2_subdev_selection *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>fd</parameter></term>
+ <listitem>
+ <para>&fd;</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>request</parameter></term>
+ <listitem>
+ <para>VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para></para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <note>
+ <title>Experimental</title>
+ <para>This is an <link linkend="experimental">experimental</link>
+ interface and may change in the future.</para>
+ </note>
+
+ <para>The selections are used to configure various image
+ processing functionality performed by the subdevs which affect the
+ image size. This currently includes cropping, scaling and
+ composition.</para>
+
+ <para>The selections replace the crop API &sub-subdev-g-crop;. All
+ the function of the crop API, and more, are supported by the
+ selections API.</para>
+
+ <para>See <xref linkend="subdev">Sub-device interface</xref> for
+ more information on how each selection target affects the image
+ processing pipeline inside the subdevice.</para>
+
+ <section>
+ <title>Types of selection targets</title>
+
+ <para>The are four types of selection targets: active, default,
+ bounds and padding. The ACTIVE targets are the targets which
+ configure the hardware. The DEFAULT target provides the default
+ for the ACTIVE selection. The BOUNDS target will return the
+ maximum width and height of the target. The PADDED target
+ provides the width and height for the padded image, and is
+ directly affected by the ACTIVE target. The PADDED targets may
+ be configurable depending on the hardware.</para>
+ </section>
+
+ <table pgwide="1" frame="none" id="v4l2-subdev-selection-targets">
+ <title>V4L2 subdev selection targets</title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_CROP_ACTIVE</constant></entry>
+ <entry>0</entry>
+ <entry>Active crop. Defines the cropping
+ performed by the processing step.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_CROP_DEFAULT</constant></entry>
+ <entry>1</entry>
+ <entry>Default crop rectangle.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_CROP_BOUNDS</constant></entry>
+ <entry>2</entry>
+ <entry>Bounds of the crop rectangle.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_COMPOSE_ACTIVE</constant></entry>
+ <entry>256</entry>
+ <entry>Active compose rectangle. Used to configure scaling
+ on sink pads and composition on source pads.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_COMPOSE_DEFAULT</constant></entry>
+ <entry>257</entry>
+ <entry>Default compose rectangle.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_TGT_COMPOSE_BOUNDS</constant></entry>
+ <entry>258</entry>
+ <entry>Bounds of the compose rectangle.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="v4l2-subdev-selection-flags">
+ <title>V4L2 subdev selection flags</title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_FLAG_SIZE_GE</constant></entry>
+ <entry>(1 << 0)</entry>
+ <entry>Suggest the driver it should choose greater or
+ equal rectangle (in size) than was requested.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_FLAG_SIZE_LE</constant></entry>
+ <entry>(1 << 1)</entry>
+ <entry>Suggest the driver it should choose lesser or
+ equal rectangle (in size) than was requested.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_SUBDEV_SEL_FLAG_KEEP_CONFIG</constant></entry>
+ <entry>(1 << 2)</entry>
+ <entry>The configuration should 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>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="v4l2-subdev-selection">
+ <title>struct <structname>v4l2_subdev_selection</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>which</structfield></entry>
+ <entry>Active or try selection, from
+ &v4l2-subdev-format-whence;.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>pad</structfield></entry>
+ <entry>Pad number as reported by the media framework.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>target</structfield></entry>
+ <entry>Target selection rectangle. See
+ <xref linkend="v4l2-subdev-selection-targets">.</xref>.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>flags</structfield></entry>
+ <entry>Flags. See
+ <xref linkend="v4l2-subdev-selection-flags">.</xref></entry>
+ </row>
+ <row>
+ <entry>&v4l2-rect;</entry>
+ <entry><structfield>rect</structfield></entry>
+ <entry>Crop rectangle boundaries, in pixels.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[8]</entry>
+ <entry>Reserved for future extensions. Applications and drivers must
+ set the array to zero.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EBUSY</errorcode></term>
+ <listitem>
+ <para>The selection rectangle can't be changed because the
+ pad is currently busy. This can be caused, for instance, by
+ an active video stream on the pad. The ioctl must not be
+ retried without performing another action to fix the problem
+ first. Only returned by
+ <constant>VIDIOC_SUBDEV_S_SELECTION</constant></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The &v4l2-subdev-selection;
+ <structfield>pad</structfield> references a non-existing
+ pad, the <structfield>which</structfield> field references a
+ non-existing format, or the selection target is not
+ supported on the given subdev pad.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
--
1.7.2.5
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