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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:02 EST.

1	<refentry id="vidioc-g-sliced-vbi-cap">
2	  <refmeta>
3	    <refentrytitle>ioctl VIDIOC_G_SLICED_VBI_CAP</refentrytitle>
4	    &manvol;
5	  </refmeta>
6	
7	  <refnamediv>
8	    <refname>VIDIOC_G_SLICED_VBI_CAP</refname>
9	    <refpurpose>Query sliced VBI capabilities</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_sliced_vbi_cap *<parameter>argp</parameter></paramdef>
19	      </funcprototype>
20	    </funcsynopsis>
21	  </refsynopsisdiv>
22	
23	  <refsect1>
24	    <title>Arguments</title>
25	
26	    <variablelist>
27	      <varlistentry>
28		<term><parameter>fd</parameter></term>
29		<listitem>
30		  <para>&fd;</para>
31		</listitem>
32	      </varlistentry>
33	      <varlistentry>
34		<term><parameter>request</parameter></term>
35		<listitem>
36		  <para>VIDIOC_G_SLICED_VBI_CAP</para>
37		</listitem>
38	      </varlistentry>
39	      <varlistentry>
40		<term><parameter>argp</parameter></term>
41		<listitem>
42		  <para></para>
43		</listitem>
44	      </varlistentry>
45	    </variablelist>
46	  </refsect1>
47	
48	  <refsect1>
49	    <title>Description</title>
50	
51	    <para>To find out which data services are supported by a sliced
52	VBI capture or output device, applications initialize the
53	<structfield>type</structfield> field of a &v4l2-sliced-vbi-cap;,
54	clear the <structfield>reserved</structfield> array and
55	call the <constant>VIDIOC_G_SLICED_VBI_CAP</constant> ioctl. The
56	driver fills in the remaining fields or returns an &EINVAL; if the
57	sliced VBI API is unsupported or <structfield>type</structfield>
58	is invalid.</para>
59	
60	    <para>Note the <structfield>type</structfield> field was added,
61	and the ioctl changed from read-only to write-read, in Linux 2.6.19.</para>
62	
63	    <table pgwide="1" frame="none" id="v4l2-sliced-vbi-cap">
64	      <title>struct <structname>v4l2_sliced_vbi_cap</structname></title>
65	      <tgroup cols="5">
66		<colspec colname="c1" colwidth="3*" />
67		<colspec colname="c2" colwidth="3*" />
68		<colspec colname="c3" colwidth="2*" />
69		<colspec colname="c4" colwidth="2*" />
70		<colspec colname="c5" colwidth="2*" />
71		<spanspec spanname="hspan" namest="c3" nameend="c5" />
72		<tbody valign="top">
73		  <row>
74		    <entry>__u16</entry>
75		    <entry><structfield>service_set</structfield></entry>
76		    <entry spanname="hspan">A set of all data services
77	supported by the driver. Equal to the union of all elements of the
78	<structfield>service_lines </structfield> array.</entry>
79		  </row>
80		  <row>
81		    <entry>__u16</entry>
82		    <entry><structfield>service_lines</structfield>[2][24]</entry>
83		    <entry spanname="hspan">Each element of this array
84	contains a set of data services the hardware can look for or insert
85	into a particular scan line. Data services are defined in <xref
86			linkend="vbi-services" />. Array indices map to ITU-R
87	line numbers (see also <xref
88			linkend="vbi-525" /> and <xref
89	linkend="vbi-625" />) as follows:</entry>
90		  </row>
91		  <row>
92		    <entry></entry>
93		    <entry></entry>
94		    <entry>Element</entry>
95		    <entry>525 line systems</entry>
96		    <entry>625 line systems</entry>
97		  </row>
98		  <row>
99		    <entry></entry>
100		    <entry></entry>
101		    <entry><structfield>service_lines</structfield>[0][1]</entry>
102		    <entry align="center">1</entry>
103		    <entry align="center">1</entry>
104		  </row>
105		  <row>
106		    <entry></entry>
107		    <entry></entry>
108		    <entry><structfield>service_lines</structfield>[0][23]</entry>
109		    <entry align="center">23</entry>
110		    <entry align="center">23</entry>
111		  </row>
112		  <row>
113		    <entry></entry>
114		    <entry></entry>
115		    <entry><structfield>service_lines</structfield>[1][1]</entry>
116		    <entry align="center">264</entry>
117		    <entry align="center">314</entry>
118		  </row>
119		  <row>
120		    <entry></entry>
121		    <entry></entry>
122		    <entry><structfield>service_lines</structfield>[1][23]</entry>
123		    <entry align="center">286</entry>
124		    <entry align="center">336</entry>
125		  </row>
126		  <row>
127		    <entry></entry>
128		  </row>
129		  <row>
130		    <entry></entry>
131		    <entry></entry>
132		    <entry spanname="hspan">The number of VBI lines the
133	hardware can capture or output per frame, or the number of services it
134	can identify on a given line may be limited. For example on PAL line
135	16 the hardware may be able to look for a VPS or Teletext signal, but
136	not both at the same time. Applications can learn about these limits
137	using the &VIDIOC-S-FMT; ioctl as described in <xref
138			linkend="sliced" />.</entry>
139		  </row>
140		  <row>
141		    <entry></entry>
142		  </row>
143		  <row>
144		    <entry></entry>
145		    <entry></entry>
146		    <entry spanname="hspan">Drivers must set
147	<structfield>service_lines</structfield>[0][0] and
148	<structfield>service_lines</structfield>[1][0] to zero.</entry>
149		  </row>
150		  <row>
151		    <entry>__u32</entry>
152		    <entry><structfield>type</structfield></entry>
153		    <entry>Type of the data stream, see <xref
154			  linkend="v4l2-buf-type" />. Should be
155	<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or
156	<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>.</entry>
157		  </row>
158		  <row>
159		    <entry>__u32</entry>
160		    <entry><structfield>reserved</structfield>[3]</entry>
161		    <entry spanname="hspan">This array is reserved for future
162	extensions. Applications and drivers must set it to zero.</entry>
163		  </row>
164		</tbody>
165	      </tgroup>
166	    </table>
167	
168	    <!-- See also dev-sliced-vbi.sgml -->
169	    <table pgwide="1" frame="none" id="vbi-services">
170	      <title>Sliced VBI services</title>
171	      <tgroup cols="5">
172		<colspec colname="c1" colwidth="2*" />
173		<colspec colname="c2" colwidth="1*" />
174		<colspec colname="c3" colwidth="1*" />
175		<colspec colname="c4" colwidth="2*" />
176		<colspec colname="c5" colwidth="2*" />
177		<spanspec spanname='rlp' namest='c3' nameend='c5' />
178		<thead>
179		  <row>
180		    <entry>Symbol</entry>
181		    <entry>Value</entry>
182		    <entry>Reference</entry>
183		    <entry>Lines, usually</entry>
184		    <entry>Payload</entry>
185		  </row>
186		</thead>
187		<tbody valign="top">
188		  <row>
189		    <entry><constant>V4L2_SLICED_TELETEXT_B</constant> (Teletext
190	System B)</entry>
191		    <entry>0x0001</entry>
192		    <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry>
193		    <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry>
194		    <entry>Last 42 of the 45 byte Teletext packet, that is
195	without clock run-in and framing code, lsb first transmitted.</entry>
196		  </row>
197		  <row>
198		    <entry><constant>V4L2_SLICED_VPS</constant></entry>
199		    <entry>0x0400</entry>
200		    <entry><xref linkend="ets300231" /></entry>
201		    <entry>PAL line 16</entry>
202		    <entry>Byte number 3 to 15 according to Figure 9 of
203	ETS&nbsp;300&nbsp;231, lsb first transmitted.</entry>
204		  </row>
205		  <row>
206		    <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry>
207		    <entry>0x1000</entry>
208		    <entry><xref linkend="eia608" /></entry>
209		    <entry>NTSC line 21, 284 (second field 21)</entry>
210		    <entry>Two bytes in transmission order, including parity
211	bit, lsb first transmitted.</entry>
212		  </row>
213		  <row>
214		    <entry><constant>V4L2_SLICED_WSS_625</constant></entry>
215		    <entry>0x4000</entry>
216		    <entry><xref linkend="en300294" />, <xref linkend="itu1119" /></entry>
217		    <entry>PAL/SECAM line 23</entry>
218		    <entry><screen>
219	Byte        0                 1
220	     msb         lsb  msb           lsb
221	Bit  7 6 5 4 3 2 1 0  x x 13 12 11 10 9
222	</screen></entry>
223		  </row>
224		  <row>
225		    <entry><constant>V4L2_SLICED_VBI_525</constant></entry>
226		    <entry>0x1000</entry>
227		    <entry spanname="rlp">Set of services applicable to 525
228	line systems.</entry>
229		  </row>
230		  <row>
231		    <entry><constant>V4L2_SLICED_VBI_625</constant></entry>
232		    <entry>0x4401</entry>
233		    <entry spanname="rlp">Set of services applicable to 625
234	line systems.</entry>
235		  </row>
236		</tbody>
237	      </tgroup>
238	    </table>
239	
240	  </refsect1>
241	
242	  <refsect1>
243	    &return-value;
244	
245	    <variablelist>
246	      <varlistentry>
247		<term><errorcode>EINVAL</errorcode></term>
248		<listitem>
249		  <para>The value in the <structfield>type</structfield> field is
250	wrong.</para>
251		</listitem>
252	      </varlistentry>
253	    </variablelist>
254	  </refsect1>
255	</refentry>
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