aboutsummaryrefslogtreecommitdiff
path: root/Documentation/DocBook/v4l/vidioc-g-sliced-vbi-cap.xml
blob: 10e721b17374d6bbd718b3b8f21f4dbe8f838dc6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
<refentry id="vidioc-g-sliced-vbi-cap">
  <refmeta>
    <refentrytitle>ioctl VIDIOC_G_SLICED_VBI_CAP</refentrytitle>
    &manvol;
  </refmeta>

  <refnamediv>
    <refname>VIDIOC_G_SLICED_VBI_CAP</refname>
    <refpurpose>Query sliced VBI capabilities</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_sliced_vbi_cap *<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_G_SLICED_VBI_CAP</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><parameter>argp</parameter></term>
	<listitem>
	  <para></para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Description</title>

    <para>To find out which data services are supported by a sliced
VBI capture or output device, applications initialize the
<structfield>type</structfield> field of a &v4l2-sliced-vbi-cap;,
clear the <structfield>reserved</structfield> array and
call the <constant>VIDIOC_G_SLICED_VBI_CAP</constant> ioctl. The
driver fills in the remaining fields or returns an &EINVAL; if the
sliced VBI API is unsupported or <structfield>type</structfield>
is invalid.</para>

    <para>Note the <structfield>type</structfield> field was added,
and the ioctl changed from read-only to write-read, in Linux 2.6.19.</para>

    <table pgwide="1" frame="none" id="v4l2-sliced-vbi-cap">
      <title>struct <structname>v4l2_sliced_vbi_cap</structname></title>
      <tgroup cols="5">
	<colspec colname="c1" colwidth="3*" />
	<colspec colname="c2" colwidth="3*" />
	<colspec colname="c3" colwidth="2*" />
	<colspec colname="c4" colwidth="2*" />
	<colspec colname="c5" colwidth="2*" />
	<spanspec spanname="hspan" namest="c3" nameend="c5" />
	<tbody valign="top">
	  <row>
	    <entry>__u16</entry>
	    <entry><structfield>service_set</structfield></entry>
	    <entry spanname="hspan">A set of all data services
supported by the driver. Equal to the union of all elements of the
<structfield>service_lines </structfield> array.</entry>
	  </row>
	  <row>
	    <entry>__u16</entry>
	    <entry><structfield>service_lines</structfield>[2][24]</entry>
	    <entry spanname="hspan">Each element of this array
contains a set of data services the hardware can look for or insert
into a particular scan line. Data services are defined in <xref
		linkend="vbi-services" />. Array indices map to ITU-R
line numbers (see also <xref
		linkend="vbi-525" /> and <xref
linkend="vbi-625" />) as follows:</entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry>Element</entry>
	    <entry>525 line systems</entry>
	    <entry>625 line systems</entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry><structfield>service_lines</structfield>[0][1]</entry>
	    <entry align="center">1</entry>
	    <entry align="center">1</entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry><structfield>service_lines</structfield>[0][23]</entry>
	    <entry align="center">23</entry>
	    <entry align="center">23</entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry><structfield>service_lines</structfield>[1][1]</entry>
	    <entry align="center">264</entry>
	    <entry align="center">314</entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry><structfield>service_lines</structfield>[1][23]</entry>
	    <entry align="center">286</entry>
	    <entry align="center">336</entry>
	  </row>
	  <row>
	    <entry></entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry spanname="hspan">The number of VBI lines the
hardware can capture or output per frame, or the number of services it
can identify on a given line may be limited. For example on PAL line
16 the hardware may be able to look for a VPS or Teletext signal, but
not both at the same time. Applications can learn about these limits
using the &VIDIOC-S-FMT; ioctl as described in <xref
		linkend="sliced" />.</entry>
	  </row>
	  <row>
	    <entry></entry>
	  </row>
	  <row>
	    <entry></entry>
	    <entry></entry>
	    <entry spanname="hspan">Drivers must set
<structfield>service_lines</structfield>[0][0] and
<structfield>service_lines</structfield>[1][0] to zero.</entry>
	  </row>
	  <row>
	    <entry>&v4l2-buf-type;</entry>
	    <entry><structfield>type</structfield></entry>
	    <entry>Type of the data stream, see <xref
		  linkend="v4l2-buf-type" />. Should be
<constant>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</constant> or
<constant>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</constant>.</entry>
	  </row>
	  <row>
	    <entry>__u32</entry>
	    <entry><structfield>reserved</structfield>[3]</entry>
	    <entry spanname="hspan">This array is reserved for future
extensions. Applications and drivers must set it to zero.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

    <!-- See also dev-sliced-vbi.sgml -->
    <table pgwide="1" frame="none" id="vbi-services">
      <title>Sliced VBI services</title>
      <tgroup cols="5">
	<colspec colname="c1" colwidth="2*" />
	<colspec colname="c2" colwidth="1*" />
	<colspec colname="c3" colwidth="1*" />
	<colspec colname="c4" colwidth="2*" />
	<colspec colname="c5" colwidth="2*" />
	<spanspec spanname='rlp' namest='c3' nameend='c5' />
	<thead>
	  <row>
	    <entry>Symbol</entry>
	    <entry>Value</entry>
	    <entry>Reference</entry>
	    <entry>Lines, usually</entry>
	    <entry>Payload</entry>
	  </row>
	</thead>
	<tbody valign="top">
	  <row>
	    <entry><constant>V4L2_SLICED_TELETEXT_B</constant> (Teletext
System B)</entry>
	    <entry>0x0001</entry>
	    <entry><xref linkend="ets300706" />, <xref linkend="itu653" /></entry>
	    <entry>PAL/SECAM line 7-22, 320-335 (second field 7-22)</entry>
	    <entry>Last 42 of the 45 byte Teletext packet, that is
without clock run-in and framing code, lsb first transmitted.</entry>
	  </row>
	  <row>
	    <entry><constant>V4L2_SLICED_VPS</constant></entry>
	    <entry>0x0400</entry>
	    <entry><xref linkend="ets300231" /></entry>
	    <entry>PAL line 16</entry>
	    <entry>Byte number 3 to 15 according to Figure 9 of
ETS&nbsp;300&nbsp;231, lsb first transmitted.</entry>
	  </row>
	  <row>
	    <entry><constant>V4L2_SLICED_CAPTION_525</constant></entry>
	    <entry>0x1000</entry>
	    <entry><xref linkend="eia608" /></entry>
	    <entry>NTSC line 21, 284 (second field 21)</entry>
	    <entry>Two bytes in transmission order, including parity
bit, lsb first transmitted.</entry>
	  </row>
	  <row>
	    <entry><constant>V4L2_SLICED_WSS_625</constant></entry>
	    <entry>0x4000</entry>
	    <entry><xref linkend="en300294" />, <xref linkend="itu1119" /></entry>
	    <entry>PAL/SECAM line 23</entry>
	    <entry><screen>
Byte        0                 1
     msb         lsb  msb           lsb
Bit  7 6 5 4 3 2 1 0  x x 13 12 11 10 9
</screen></entry>
	  </row>
	  <row>
	    <entry><constant>V4L2_SLICED_VBI_525</constant></entry>
	    <entry>0x1000</entry>
	    <entry spanname="rlp">Set of services applicable to 525
line systems.</entry>
	  </row>
	  <row>
	    <entry><constant>V4L2_SLICED_VBI_625</constant></entry>
	    <entry>0x4401</entry>
	    <entry spanname="rlp">Set of services applicable to 625
line systems.</entry>
	  </row>
	</tbody>
      </tgroup>
    </table>

  </refsect1>

  <refsect1>
    &return-value;

    <variablelist>
      <varlistentry>
	<term><errorcode>EINVAL</errorcode></term>
	<listitem>
	  <para>The device does not support sliced VBI capturing or
output, or the value in the <structfield>type</structfield> field is
wrong.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
</refentry>

<!--
Local Variables:
mode: sgml
sgml-parent-document: "v4l2.sgml"
indent-tabs-mode: nil
End:
-->