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>Introduction</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="PREVIOUS" 13TITLE="Video for Linux Two API Specification" 14HREF="book1.htm"><LINK 15REL="NEXT" 16TITLE="Common API Elements" 17HREF="c174.htm"></HEAD 18><BODY 19CLASS="PREFACE" 20BGCOLOR="#FFFFFF" 21TEXT="#000000" 22LINK="#0000FF" 23VLINK="#840084" 24ALINK="#0000FF" 25><DIV 26CLASS="NAVHEADER" 27><TABLE 28SUMMARY="Header navigation table" 29WIDTH="100%" 30BORDER="0" 31CELLPADDING="0" 32CELLSPACING="0" 33><TR 34><TH 35COLSPAN="3" 36ALIGN="center" 37>Video for Linux Two API Specification: Revision 0.24</TH 38></TR 39><TR 40><TD 41WIDTH="10%" 42ALIGN="left" 43VALIGN="bottom" 44><A 45HREF="book1.htm" 46ACCESSKEY="P" 47>Prev</A 48></TD 49><TD 50WIDTH="80%" 51ALIGN="center" 52VALIGN="bottom" 53></TD 54><TD 55WIDTH="10%" 56ALIGN="right" 57VALIGN="bottom" 58><A 59HREF="c174.htm" 60ACCESSKEY="N" 61>Next</A 62></TD 63></TR 64></TABLE 65><HR 66ALIGN="LEFT" 67WIDTH="100%"></DIV 68><DIV 69CLASS="PREFACE" 70><H1 71><A 72NAME="AEN163" 73></A 74>Introduction</H1 75><P 76>Video For Linux Two is the second version of the Video For 77Linux API, a kernel interface for analog radio and video capture and 78output drivers.</P 79><P 80>Early drivers used ad-hoc interfaces. These were replaced in 81Linux 2.2 by Alan Cox' V4L API, based on the interface of the bttv 82driver. In 1999 Bill Dirks started the development of V4L2 to fix some 83shortcomings of V4L and to support a wider range of devices. The API 84was revised again in 2002 prior to its inclusion in Linux 2.5/2.6, and 85work continues on improvements and additions while maintaining 86compatibility with existing drivers and applications. In 2006/2007 87efforts began on FreeBSD drivers with a V4L2 interface.</P 88><P 89>This book documents the V4L2 API. Intended audience are 90driver and application writers.</P 91><P 92>If you have questions or ideas regarding the API, please 93write to the Video4Linux mailing list: <A 94HREF="https://listman.redhat.com/mailman/listinfo/video4linux-list" 95TARGET="_top" 96>https://listman.redhat.com/mailman/listinfo/video4linux-list</A 97>. For inquiries about 98the V4L2 specification contact the maintainer <A 99HREF="mailto:mschimek@gmx.at" 100TARGET="_top" 101>mschimek@gmx.at</A 102>.</P 103><P 104>The latest version of this document and the DocBook SGML 105sources are hosted at <A 106HREF="../index.html" 107TARGET="_top" 108>http://v4l2spec.bytesex.org</A 109>, 110and <A 111HREF="http://linuxtv.org/downloads/video4linux/API/V4L2_API" 112TARGET="_top" 113>http://linuxtv.org/downloads/video4linux/API/V4L2_API</A 114>.</P 115></DIV 116><DIV 117CLASS="NAVFOOTER" 118><HR 119ALIGN="LEFT" 120WIDTH="100%"><TABLE 121SUMMARY="Footer navigation table" 122WIDTH="100%" 123BORDER="0" 124CELLPADDING="0" 125CELLSPACING="0" 126><TR 127><TD 128WIDTH="33%" 129ALIGN="left" 130VALIGN="top" 131><A 132HREF="book1.htm" 133ACCESSKEY="P" 134>Prev</A 135></TD 136><TD 137WIDTH="34%" 138ALIGN="center" 139VALIGN="top" 140><A 141HREF="book1.htm" 142ACCESSKEY="H" 143>Home</A 144></TD 145><TD 146WIDTH="33%" 147ALIGN="right" 148VALIGN="top" 149><A 150HREF="c174.htm" 151ACCESSKEY="N" 152>Next</A 153></TD 154></TR 155><TR 156><TD 157WIDTH="33%" 158ALIGN="left" 159VALIGN="top" 160>Video for Linux Two API Specification</TD 161><TD 162WIDTH="34%" 163ALIGN="center" 164VALIGN="top" 165> </TD 166><TD 167WIDTH="33%" 168ALIGN="right" 169VALIGN="top" 170>Common API Elements</TD 171></TR 172></TABLE 173></DIV 174></BODY 175></HTML 176> 177