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+<refentry id="vidioc-enum-framesizes">
+
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_ENUM_FRAMESIZES</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_ENUM_FRAMESIZES</refname>
+ <refpurpose>Enumerate 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_frmsizeenum *<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_ENUM_FRAMESIZES</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para>Pointer to a &v4l2-frmsizeenum; that contains an index
+and pixel format and receives a frame width and height.</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
+(&ie; width and height in pixels) that the device supports for the
+given pixel format.</para>
+ <para>The supported pixel formats can be obtained by using the
+&VIDIOC-ENUM-FMT; function.</para>
+ <para>The return value and the content of the
+<structfield>v4l2_frmsizeenum.type</structfield> field depend on the
+type of frame sizes the device supports. Here are the semantics of the
+function for the different cases:</para>
+
+ <itemizedlist>
+ <listitem>
+ <para><emphasis role="bold">Discrete:</emphasis> The function
+returns success if the given index value (zero-based) is valid. The
+application should increase the index by one for each call until
+<constant>EINVAL</constant> is returned. The
+<structfield>v4l2_frmsizeenum.type</structfield> field is set to
+<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> by the driver. Of the
+union only the <structfield>discrete</structfield> member is
+valid.</para>
+ </listitem>
+ <listitem>
+ <para><emphasis role="bold">Step-wise:</emphasis> The function
+returns success if the given index value is zero and
+<constant>EINVAL</constant> for any other index value. The
+<structfield>v4l2_frmsizeenum.type</structfield> field is set to
+<constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant> by the driver. Of the
+union only the <structfield>stepwise</structfield> member is
+valid.</para>
+ </listitem>
+ <listitem>
+ <para><emphasis role="bold">Continuous:</emphasis> This is a
+special case of the step-wise type above. The function returns success
+if the given index value is zero and <constant>EINVAL</constant> for
+any other index value. The
+<structfield>v4l2_frmsizeenum.type</structfield> field is set to
+<constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant> by the driver. Of
+the union only the <structfield>stepwise</structfield> member is valid
+and the <structfield>step_width</structfield> and
+<structfield>step_height</structfield> values are set to 1.</para>
+ </listitem>
+ </itemizedlist>
+
+ <para>When the application calls the function with index zero, it
+must check the <structfield>type</structfield> field to determine the
+type of frame size enumeration the device supports. Only for the
+<constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant> type does it make
+sense to increase the index value to receive more frame sizes.</para>
+ <para>Note that the order in which the frame sizes are returned
+has no special meaning. In particular does it not say anything about
+potential default format sizes.</para>
+ <para>Applications can assume that the enumeration data does not
+change without any interaction from the application itself. This means
+that the enumeration data is consistent if the application does not
+perform any other ioctl calls while it runs the frame size
+enumeration.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Structs</title>
+
+ <para>In the structs below, <emphasis>IN</emphasis> denotes a
+value that has to be filled in by the application,
+<emphasis>OUT</emphasis> denotes values that the driver fills in. The
+application should zero out all members except for the
+<emphasis>IN</emphasis> fields.</para>
+
+ <table pgwide="1" frame="none" id="v4l2-frmsize-discrete">
+ <title>struct <structname>v4l2_frmsize_discrete</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>width</structfield></entry>
+ <entry>Width of the frame [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>height</structfield></entry>
+ <entry>Height of the frame [pixel].</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="v4l2-frmsize-stepwise">
+ <title>struct <structname>v4l2_frmsize_stepwise</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>min_width</structfield></entry>
+ <entry>Minimum frame width [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>max_width</structfield></entry>
+ <entry>Maximum frame width [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>step_width</structfield></entry>
+ <entry>Frame width step size [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>min_height</structfield></entry>
+ <entry>Minimum frame height [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>max_height</structfield></entry>
+ <entry>Maximum frame height [pixel].</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>step_height</structfield></entry>
+ <entry>Frame height step size [pixel].</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <table pgwide="1" frame="none" id="v4l2-frmsizeenum">
+ <title>struct <structname>v4l2_frmsizeenum</structname></title>
+ <tgroup cols="4">
+ <colspec colname="c1" />
+ <colspec colname="c2" />
+ <colspec colname="c3" />
+ <colspec colname="c4" />
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>index</structfield></entry>
+ <entry></entry>
+ <entry>IN: Index of the given frame size in the enumeration.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>pixel_format</structfield></entry>
+ <entry></entry>
+ <entry>IN: Pixel format for which the frame sizes are enumerated.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>type</structfield></entry>
+ <entry></entry>
+ <entry>OUT: Frame size type the device supports.</entry>
+ </row>
+ <row>
+ <entry>union</entry>
+ <entry></entry>
+ <entry></entry>
+ <entry>OUT: Frame size with the given index.</entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry>&v4l2-frmsize-discrete;</entry>
+ <entry><structfield>discrete</structfield></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry></entry>
+ <entry>&v4l2-frmsize-stepwise;</entry>
+ <entry><structfield>stepwise</structfield></entry>
+ <entry></entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved[2]</structfield></entry>
+ <entry></entry>
+ <entry>Reserved space for future use.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ <title>Enums</title>
+
+ <table pgwide="1" frame="none" id="v4l2-frmsizetypes">
+ <title>enum <structname>v4l2_frmsizetypes</structname></title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_FRMSIZE_TYPE_DISCRETE</constant></entry>
+ <entry>1</entry>
+ <entry>Discrete frame size.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_FRMSIZE_TYPE_CONTINUOUS</constant></entry>
+ <entry>2</entry>
+ <entry>Continuous frame size.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_FRMSIZE_TYPE_STEPWISE</constant></entry>
+ <entry>3</entry>
+ <entry>Step-wise defined frame size.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <para>See the description section above for a list of return
+values that <varname>errno</varname> can have.</para>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->
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