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<refentry id="vidioc-subdev-enum-frame-size">
<refmeta>
<refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refname>
<refpurpose>Enumerate media bus frame sizes</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_frame_size_enum *
<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_ENUM_FRAME_SIZE</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>This ioctl allows applications to enumerate all frame sizes
supported by a sub-device on the given pad for the given media bus format.
Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE;
ioctl.</para>
<para>To enumerate frame sizes applications initialize the
<structfield>pad</structfield>, <structfield>which</structfield> ,
<structfield>code</structfield> and <structfield>index</structfield>
fields of the &v4l2-subdev-mbus-code-enum; and call the
<constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to
the structure. Drivers fill the minimum and maximum frame sizes or return
an &EINVAL; if one of the input parameters is invalid.</para>
<para>Sub-devices that only support discrete frame sizes (such as most
sensors) will return one or more frame sizes with identical minimum and
maximum values.</para>
<para>Not all possible sizes in given [minimum, maximum] ranges need to be
supported. For instance, a scaler that uses a fixed-point scaling ratio
might not be able to produce every frame size between the minimum and
maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to
try the sub-device for an exact supported frame size.</para>
<para>Available frame sizes may depend on the current 'try' formats at other
pads of the sub-device, as well as on the current active links and the
current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more
information about try formats.</para>
<table pgwide="1" frame="none" id="v4l2-subdev-frame-size-enum">
<title>struct <structname>v4l2_subdev_frame_size_enum</structname></title>
<tgroup cols="3">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>index</structfield></entry>
<entry>Number of the format in the enumeration, set by the
application.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>pad</structfield></entry>
<entry>Pad number as reported by the media controller API.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>code</structfield></entry>
<entry>The media bus format code, as defined in
<xref linkend="v4l2-mbus-format" />.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>min_width</structfield></entry>
<entry>Minimum frame width, in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>max_width</structfield></entry>
<entry>Maximum frame width, in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>min_height</structfield></entry>
<entry>Minimum frame height, in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>max_height</structfield></entry>
<entry>Maximum frame height, in pixels.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>which</structfield></entry>
<entry>Frame sizes to be enumerated, from &v4l2-subdev-format-whence;.</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>EINVAL</errorcode></term>
<listitem>
<para>The &v4l2-subdev-frame-size-enum; <structfield>pad</structfield>
references a non-existing pad, the <structfield>code</structfield> is
invalid for the given pad or the <structfield>index</structfield>
field is out of bounds.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
|
