1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> 2<HTML 3><HEAD 4><TITLE 5>ioctl VIDIOC_OVERLAY</TITLE 6><META 7NAME="GENERATOR" 8CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK 9REL="HOME" 10TITLE="Video for Linux Two API Specification" 11HREF="book1.htm"><LINK 12REL="UP" 13TITLE="Function Reference" 14HREF="r7624.htm"><LINK 15REL="PREVIOUS" 16TITLE="ioctl VIDIOC_LOG_STATUS" 17HREF="r12784.htm"><LINK 18REL="NEXT" 19TITLE="ioctl VIDIOC_QBUF, VIDIOC_DQBUF" 20HREF="r12878.htm"></HEAD 21><BODY 22CLASS="REFENTRY" 23BGCOLOR="#FFFFFF" 24TEXT="#000000" 25LINK="#0000FF" 26VLINK="#840084" 27ALINK="#0000FF" 28><DIV 29CLASS="NAVHEADER" 30><TABLE 31SUMMARY="Header navigation table" 32WIDTH="100%" 33BORDER="0" 34CELLPADDING="0" 35CELLSPACING="0" 36><TR 37><TH 38COLSPAN="3" 39ALIGN="center" 40>Video for Linux Two API Specification: Revision 0.24</TH 41></TR 42><TR 43><TD 44WIDTH="10%" 45ALIGN="left" 46VALIGN="bottom" 47><A 48HREF="r12784.htm" 49ACCESSKEY="P" 50>Prev</A 51></TD 52><TD 53WIDTH="80%" 54ALIGN="center" 55VALIGN="bottom" 56></TD 57><TD 58WIDTH="10%" 59ALIGN="right" 60VALIGN="bottom" 61><A 62HREF="r12878.htm" 63ACCESSKEY="N" 64>Next</A 65></TD 66></TR 67></TABLE 68><HR 69ALIGN="LEFT" 70WIDTH="100%"></DIV 71><H1 72><A 73NAME="VIDIOC-OVERLAY" 74></A 75>ioctl VIDIOC_OVERLAY</H1 76><DIV 77CLASS="REFNAMEDIV" 78><A 79NAME="AEN12820" 80></A 81><H2 82>Name</H2 83>VIDIOC_OVERLAY -- Start or stop video overlay</DIV 84><DIV 85CLASS="REFSYNOPSISDIV" 86><A 87NAME="AEN12823" 88></A 89><H2 90>Synopsis</H2 91><DIV 92CLASS="FUNCSYNOPSIS" 93><P 94></P 95><A 96NAME="AEN12824" 97></A 98><P 99><CODE 100><CODE 101CLASS="FUNCDEF" 102>int ioctl</CODE 103>(int fd, int request, const int *argp);</CODE 104></P 105><P 106></P 107></DIV 108></DIV 109><DIV 110CLASS="REFSECT1" 111><A 112NAME="AEN12834" 113></A 114><H2 115>Arguments</H2 116><P 117></P 118><DIV 119CLASS="VARIABLELIST" 120><DL 121><DT 122><CODE 123CLASS="PARAMETER" 124>fd</CODE 125></DT 126><DD 127><P 128>File descriptor returned by <A 129HREF="r14090.htm" 130><CODE 131CLASS="FUNCTION" 132>open()</CODE 133></A 134>.</P 135></DD 136><DT 137><CODE 138CLASS="PARAMETER" 139>request</CODE 140></DT 141><DD 142><P 143>VIDIOC_OVERLAY</P 144></DD 145><DT 146><CODE 147CLASS="PARAMETER" 148>argp</CODE 149></DT 150><DD 151><P 152></P 153></DD 154></DL 155></DIV 156></DIV 157><DIV 158CLASS="REFSECT1" 159><A 160NAME="AEN12854" 161></A 162><H2 163>Description</H2 164><P 165>This ioctl is part of the <A 166HREF="x6570.htm" 167>video 168 overlay</A 169> I/O method. Applications call 170 <CODE 171CLASS="CONSTANT" 172>VIDIOC_OVERLAY</CODE 173> to start or stop the 174 overlay. It takes a pointer to an integer which must be set to 175 zero by the application to stop overlay, to one to start.</P 176><P 177>Drivers do not support <A 178HREF="r13817.htm" 179><CODE 180CLASS="CONSTANT" 181>VIDIOC_STREAMON</CODE 182></A 183> or 184<A 185HREF="r13817.htm" 186><CODE 187CLASS="CONSTANT" 188>VIDIOC_STREAMOFF</CODE 189></A 190> with <CODE 191CLASS="CONSTANT" 192>V4L2_BUF_TYPE_VIDEO_OVERLAY</CODE 193>.</P 194></DIV 195><DIV 196CLASS="REFSECT1" 197><A 198NAME="AEN12865" 199></A 200><H2 201>Return Value</H2 202><P 203>On success <SPAN 204CLASS="RETURNVALUE" 205>0</SPAN 206> is returned, on error <SPAN 207CLASS="RETURNVALUE" 208>-1</SPAN 209> and the <CODE 210CLASS="VARNAME" 211>errno</CODE 212> variable is set appropriately:</P 213><P 214></P 215><DIV 216CLASS="VARIABLELIST" 217><DL 218><DT 219><SPAN 220CLASS="ERRORCODE" 221>EINVAL</SPAN 222></DT 223><DD 224><P 225>Video overlay is not supported, or the 226parameters have not been set up. See <A 227HREF="x6570.htm" 228>Section 4.2</A 229> for the necessary steps.</P 230></DD 231></DL 232></DIV 233></DIV 234><DIV 235CLASS="NAVFOOTER" 236><HR 237ALIGN="LEFT" 238WIDTH="100%"><TABLE 239SUMMARY="Footer navigation table" 240WIDTH="100%" 241BORDER="0" 242CELLPADDING="0" 243CELLSPACING="0" 244><TR 245><TD 246WIDTH="33%" 247ALIGN="left" 248VALIGN="top" 249><A 250HREF="r12784.htm" 251ACCESSKEY="P" 252>Prev</A 253></TD 254><TD 255WIDTH="34%" 256ALIGN="center" 257VALIGN="top" 258><A 259HREF="book1.htm" 260ACCESSKEY="H" 261>Home</A 262></TD 263><TD 264WIDTH="33%" 265ALIGN="right" 266VALIGN="top" 267><A 268HREF="r12878.htm" 269ACCESSKEY="N" 270>Next</A 271></TD 272></TR 273><TR 274><TD 275WIDTH="33%" 276ALIGN="left" 277VALIGN="top" 278>ioctl VIDIOC_LOG_STATUS</TD 279><TD 280WIDTH="34%" 281ALIGN="center" 282VALIGN="top" 283><A 284HREF="r7624.htm" 285ACCESSKEY="U" 286>Up</A 287></TD 288><TD 289WIDTH="33%" 290ALIGN="right" 291VALIGN="top" 292>ioctl VIDIOC_QBUF, VIDIOC_DQBUF</TD 293></TR 294></TABLE 295></DIV 296></BODY 297></HTML 298> 299