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1<refentry id="vidioc-g-dv-timings">
2  <refmeta>
3    <refentrytitle>ioctl VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</refentrytitle>
4    &manvol;
5  </refmeta>
6
7  <refnamediv>
8    <refname>VIDIOC_G_DV_TIMINGS</refname>
9    <refname>VIDIOC_S_DV_TIMINGS</refname>
10    <refpurpose>Get or set custom DV timings for input or output</refpurpose>
11  </refnamediv>
12
13  <refsynopsisdiv>
14    <funcsynopsis>
15      <funcprototype>
16	<funcdef>int <function>ioctl</function></funcdef>
17	<paramdef>int <parameter>fd</parameter></paramdef>
18	<paramdef>int <parameter>request</parameter></paramdef>
19	<paramdef>&v4l2-dv-timings;
20*<parameter>argp</parameter></paramdef>
21      </funcprototype>
22    </funcsynopsis>
23  </refsynopsisdiv>
24
25  <refsect1>
26    <title>Arguments</title>
27
28    <variablelist>
29      <varlistentry>
30	<term><parameter>fd</parameter></term>
31	<listitem>
32	  <para>&fd;</para>
33	</listitem>
34      </varlistentry>
35      <varlistentry>
36	<term><parameter>request</parameter></term>
37	<listitem>
38	  <para>VIDIOC_G_DV_TIMINGS, VIDIOC_S_DV_TIMINGS</para>
39	</listitem>
40      </varlistentry>
41      <varlistentry>
42	<term><parameter>argp</parameter></term>
43	<listitem>
44	  <para></para>
45	</listitem>
46      </varlistentry>
47    </variablelist>
48  </refsect1>
49
50  <refsect1>
51    <title>Description</title>
52    <para>To set custom DV timings for the input or output, applications use the
53<constant>VIDIOC_S_DV_TIMINGS</constant> ioctl and to get the current custom timings,
54applications use the <constant>VIDIOC_G_DV_TIMINGS</constant> ioctl. The detailed timing
55information is filled in using the structure &v4l2-dv-timings;. These ioctls take
56a pointer to the &v4l2-dv-timings; structure as argument. If the ioctl is not supported
57or the timing values are not correct, the driver returns &EINVAL;.</para>
58  </refsect1>
59
60  <refsect1>
61    &return-value;
62
63    <variablelist>
64      <varlistentry>
65	<term><errorcode>EINVAL</errorcode></term>
66	<listitem>
67	  <para>This ioctl is not supported, or the
68<constant>VIDIOC_S_DV_TIMINGS</constant> parameter was unsuitable.</para>
69	</listitem>
70      </varlistentry>
71      <varlistentry>
72	<term><errorcode>EBUSY</errorcode></term>
73	<listitem>
74	  <para>The device is busy and therefore can not change the timings.</para>
75	</listitem>
76      </varlistentry>
77    </variablelist>
78
79    <table pgwide="1" frame="none" id="v4l2-bt-timings">
80      <title>struct <structname>v4l2_bt_timings</structname></title>
81      <tgroup cols="3">
82	&cs-str;
83	<tbody valign="top">
84	  <row>
85	    <entry>__u32</entry>
86	    <entry><structfield>width</structfield></entry>
87	    <entry>Width of the active video in pixels</entry>
88	  </row>
89	  <row>
90	    <entry>__u32</entry>
91	    <entry><structfield>height</structfield></entry>
92	    <entry>Height of the active video in lines</entry>
93	  </row>
94	  <row>
95	    <entry>__u32</entry>
96	    <entry><structfield>interlaced</structfield></entry>
97	    <entry>Progressive (0) or interlaced (1)</entry>
98	  </row>
99	  <row>
100	    <entry>__u32</entry>
101	    <entry><structfield>polarities</structfield></entry>
102	    <entry>This is a bit mask that defines polarities of sync signals.
103bit 0 (V4L2_DV_VSYNC_POS_POL) is for vertical sync polarity and bit 1 (V4L2_DV_HSYNC_POS_POL) is for horizontal sync polarity. If the bit is set
104(1) it is positive polarity and if is cleared (0), it is negative polarity.</entry>
105	  </row>
106	  <row>
107	    <entry>__u64</entry>
108	    <entry><structfield>pixelclock</structfield></entry>
109	    <entry>Pixel clock in Hz. Ex. 74.25MHz->74250000</entry>
110	  </row>
111	  <row>
112	    <entry>__u32</entry>
113	    <entry><structfield>hfrontporch</structfield></entry>
114	    <entry>Horizontal front porch in pixels</entry>
115	  </row>
116	  <row>
117	    <entry>__u32</entry>
118	    <entry><structfield>hsync</structfield></entry>
119	    <entry>Horizontal sync length in pixels</entry>
120	  </row>
121	  <row>
122	    <entry>__u32</entry>
123	    <entry><structfield>hbackporch</structfield></entry>
124	    <entry>Horizontal back porch in pixels</entry>
125	  </row>
126	  <row>
127	    <entry>__u32</entry>
128	    <entry><structfield>vfrontporch</structfield></entry>
129	    <entry>Vertical front porch in lines</entry>
130	  </row>
131	  <row>
132	    <entry>__u32</entry>
133	    <entry><structfield>vsync</structfield></entry>
134	    <entry>Vertical sync length in lines</entry>
135	  </row>
136	  <row>
137	    <entry>__u32</entry>
138	    <entry><structfield>vbackporch</structfield></entry>
139	    <entry>Vertical back porch in lines</entry>
140	  </row>
141	  <row>
142	    <entry>__u32</entry>
143	    <entry><structfield>il_vfrontporch</structfield></entry>
144	    <entry>Vertical front porch in lines for bottom field of interlaced field formats</entry>
145	  </row>
146	  <row>
147	    <entry>__u32</entry>
148	    <entry><structfield>il_vsync</structfield></entry>
149	    <entry>Vertical sync length in lines for bottom field of interlaced field formats</entry>
150	  </row>
151	  <row>
152	    <entry>__u32</entry>
153	    <entry><structfield>il_vbackporch</structfield></entry>
154	    <entry>Vertical back porch in lines for bottom field of interlaced field formats</entry>
155	  </row>
156	</tbody>
157      </tgroup>
158    </table>
159
160    <table pgwide="1" frame="none" id="v4l2-dv-timings">
161      <title>struct <structname>v4l2_dv_timings</structname></title>
162      <tgroup cols="4">
163	&cs-str;
164	<tbody valign="top">
165	  <row>
166	    <entry>__u32</entry>
167	    <entry><structfield>type</structfield></entry>
168	    <entry></entry>
169	    <entry>Type of DV timings as listed in <xref linkend="dv-timing-types"/>.</entry>
170	  </row>
171	  <row>
172	    <entry>union</entry>
173	    <entry><structfield></structfield></entry>
174	    <entry></entry>
175	  </row>
176	  <row>
177	    <entry></entry>
178	    <entry>&v4l2-bt-timings;</entry>
179	    <entry><structfield>bt</structfield></entry>
180	    <entry>Timings defined by BT.656/1120 specifications</entry>
181	  </row>
182	  <row>
183	    <entry></entry>
184	    <entry>__u32</entry>
185	    <entry><structfield>reserved</structfield>[32]</entry>
186	    <entry></entry>
187	  </row>
188	</tbody>
189      </tgroup>
190    </table>
191
192    <table pgwide="1" frame="none" id="dv-timing-types">
193      <title>DV Timing types</title>
194      <tgroup cols="3">
195	&cs-str;
196	<tbody valign="top">
197	  <row>
198	    <entry>Timing type</entry>
199	    <entry>value</entry>
200	    <entry>Description</entry>
201	  </row>
202	  <row>
203	    <entry></entry>
204	    <entry></entry>
205	    <entry></entry>
206	  </row>
207	  <row>
208	    <entry>V4L2_DV_BT_656_1120</entry>
209	    <entry>0</entry>
210	    <entry>BT.656/1120 timings</entry>
211	  </row>
212	</tbody>
213      </tgroup>
214    </table>
215  </refsect1>
216</refentry>
217
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