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Based on kernel version 3.13. Page generated on 2014-01-20 22:02 EST.

1	<refentry id="vidioc-subdev-enum-frame-size">
2	  <refmeta>
3	    <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refentrytitle>
4	    &manvol;
5	  </refmeta>
6	
7	  <refnamediv>
8	    <refname>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refname>
9	    <refpurpose>Enumerate media bus frame sizes</refpurpose>
10	  </refnamediv>
11	
12	  <refsynopsisdiv>
13	    <funcsynopsis>
14	      <funcprototype>
15		<funcdef>int <function>ioctl</function></funcdef>
16		<paramdef>int <parameter>fd</parameter></paramdef>
17		<paramdef>int <parameter>request</parameter></paramdef>
18		<paramdef>struct v4l2_subdev_frame_size_enum *
19		<parameter>argp</parameter></paramdef>
20	      </funcprototype>
21	    </funcsynopsis>
22	  </refsynopsisdiv>
23	
24	  <refsect1>
25	    <title>Arguments</title>
26	
27	    <variablelist>
28	      <varlistentry>
29		<term><parameter>fd</parameter></term>
30		<listitem>
31		  <para>&fd;</para>
32		</listitem>
33	      </varlistentry>
34	      <varlistentry>
35		<term><parameter>request</parameter></term>
36		<listitem>
37		  <para>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</para>
38		</listitem>
39	      </varlistentry>
40	      <varlistentry>
41		<term><parameter>argp</parameter></term>
42		<listitem>
43		  <para></para>
44		</listitem>
45	      </varlistentry>
46	    </variablelist>
47	  </refsect1>
48	
49	  <refsect1>
50	    <title>Description</title>
51	
52	    <note>
53	      <title>Experimental</title>
54	      <para>This is an <link linkend="experimental">experimental</link>
55	      interface and may change in the future.</para>
56	    </note>
57	
58	    <para>This ioctl allows applications to enumerate all frame sizes
59	    supported by a sub-device on the given pad for the given media bus format.
60	    Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE;
61	    ioctl.</para>
62	
63	    <para>To enumerate frame sizes applications initialize the
64	    <structfield>pad</structfield>, <structfield>code</structfield> and
65	    <structfield>index</structfield> fields of the
66	    &v4l2-subdev-mbus-code-enum; and call the
67	    <constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to
68	    the structure. Drivers fill the minimum and maximum frame sizes or return
69	    an &EINVAL; if one of the input parameters is invalid.</para>
70	
71	    <para>Sub-devices that only support discrete frame sizes (such as most
72	    sensors) will return one or more frame sizes with identical minimum and
73	    maximum values.</para>
74	
75	    <para>Not all possible sizes in given [minimum, maximum] ranges need to be
76	    supported. For instance, a scaler that uses a fixed-point scaling ratio
77	    might not be able to produce every frame size between the minimum and
78	    maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to
79	    try the sub-device for an exact supported frame size.</para>
80	
81	    <para>Available frame sizes may depend on the current 'try' formats at other
82	    pads of the sub-device, as well as on the current active links and the
83	    current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more
84	    information about try formats.</para>
85	
86	    <table pgwide="1" frame="none" id="v4l2-subdev-frame-size-enum">
87	      <title>struct <structname>v4l2_subdev_frame_size_enum</structname></title>
88	      <tgroup cols="3">
89		&cs-str;
90		<tbody valign="top">
91		  <row>
92		    <entry>__u32</entry>
93		    <entry><structfield>index</structfield></entry>
94		    <entry>Number of the format in the enumeration, set by the
95		    application.</entry>
96		  </row>
97		  <row>
98		    <entry>__u32</entry>
99		    <entry><structfield>pad</structfield></entry>
100		    <entry>Pad number as reported by the media controller API.</entry>
101		  </row>
102		  <row>
103		    <entry>__u32</entry>
104		    <entry><structfield>code</structfield></entry>
105		    <entry>The media bus format code, as defined in
106		    <xref linkend="v4l2-mbus-format" />.</entry>
107		  </row>
108		  <row>
109		    <entry>__u32</entry>
110		    <entry><structfield>min_width</structfield></entry>
111		    <entry>Minimum frame width, in pixels.</entry>
112		  </row>
113		  <row>
114		    <entry>__u32</entry>
115		    <entry><structfield>max_width</structfield></entry>
116		    <entry>Maximum frame width, in pixels.</entry>
117		  </row>
118		  <row>
119		    <entry>__u32</entry>
120		    <entry><structfield>min_height</structfield></entry>
121		    <entry>Minimum frame height, in pixels.</entry>
122		  </row>
123		  <row>
124		    <entry>__u32</entry>
125		    <entry><structfield>max_height</structfield></entry>
126		    <entry>Maximum frame height, in pixels.</entry>
127		  </row>
128		  <row>
129		    <entry>__u32</entry>
130		    <entry><structfield>reserved</structfield>[9]</entry>
131		    <entry>Reserved for future extensions. Applications and drivers must
132		    set the array to zero.</entry>
133		  </row>
134		</tbody>
135	      </tgroup>
136	    </table>
137	  </refsect1>
138	
139	  <refsect1>
140	    &return-value;
141	
142	    <variablelist>
143	      <varlistentry>
144		<term><errorcode>EINVAL</errorcode></term>
145		<listitem>
146		  <para>The &v4l2-subdev-frame-size-enum; <structfield>pad</structfield>
147		  references a non-existing pad, the <structfield>code</structfield> is
148		  invalid for the given pad or the <structfield>index</structfield>
149		  field is out of bounds.</para>
150		</listitem>
151	      </varlistentry>
152	    </variablelist>
153	  </refsect1>
154	</refentry>
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