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</style><link charset="utf-8" type="text/css" rel="stylesheet" href="http://www.w3.org/StyleSheets/TR/W3C-WD"></head><body style="display: inherit;"><div class="head"><p><a href="http://www.w3.org/"><img src="http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72"></a></p><h1 class="title" id="title">The Media Capture API</h1><h2 id="w3c-working-draft-28-september-2010">W3C Working Draft 28 September 2010</h2><dl><dt>This version:</dt><dd><a href="http://www.w3.org/TR/2010/WD-media-capture-api-20100928/">http://www.w3.org/TR/2010/WD-media-capture-api-20100928/</a></dd><dt>Latest published version:</dt><dd><a href="http://www.w3.org/TR/media-capture-api/">http://www.w3.org/TR/media-capture-api/</a></dd><dt>Latest editor's draft:</dt><dd><a href="http://dev.w3.org/2009/dap/camera/Overview-API">http://dev.w3.org/2009/dap/camera/Overview-API</a></dd><dt>Editors:</dt><dd><span>Dzung D Tran</span>, Intel</dd>
<dd><span>Ilkka Oksanen</span>, Nokia</dd>
<dd><span>Ingmar Kliche</span>, Deutsche Telekom</dd>
</dl><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2010 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p><hr></div>
<div class="introductory section" id="abstract"><h2>Abstract</h2>
This specification defines an Application Programming Interface
(<acronym title="Application Programming Interface">API</acronym>)
that provides access to the audio, image and video capture
capabilities of the device.
</div><div id="sotd" class="introductory section"><h2>Status of This Document</h2><p><em>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/">W3C technical reports index</a> at http://www.w3.org/TR/.</em></p>
<p>This document represents the early consensus of the group on
the scope and features of the proposed Capture
API. Issues and editors notes in the document highlight some of
the points on which the group is still working and would
particularly like to get feedback.</p>
<p>This document was published by the <a href="http://www.w3.org/2009/dap/">Device APIs and Policy Working Group</a> as a First Public Working Draft. This document is intended to become a W3C Recommendation. If you wish to make comments regarding this document, please send them to <a href="mailto:public-device-apis@w3.org">public-device-apis@w3.org</a> (<a href="mailto:public-device-apis-request@w3.org?subject=subscribe">subscribe</a>, <a href="http://lists.w3.org/Archives/Public/public-device-apis/">archives</a>). All feedback is welcome.</p><p>Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.</p><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/43696/status" rel="disclosure">public list of any patent disclosures</a> made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the W3C Patent Policy</a>.</p></div><div class="section" id="toc"><h2 class="introductory">Table of Contents</h2><ul class="toc"><li class="tocline"><a class="tocxref" href="#introduction"><span class="secno">1. </span>Introduction</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#examples"><span class="secno">1.1 </span>Usage Examples</a></li><li class="tocline"><a class="tocxref" href="#terminology"><span class="secno">1.2 </span>Terminology</a></li></ul></li><li class="tocline"><a class="tocxref" href="#security"><span class="secno">2. </span>Security and Privacy Considerations</a></li><li class="tocline"><a class="tocxref" href="#api"><span class="secno">3. </span>API Description</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#devicecapture-interface"><span class="secno">3.1 </span><span class="idlType formerLink idlType"><code>DeviceCapture</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes"><span class="secno">3.1.1 </span>Attributes</a></li></ul></li><li class="tocline"><a class="tocxref" href="#capture-interface"><span class="secno">3.2 </span><span class="idlType formerLink idlType"><code>Capture</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes-1"><span class="secno">3.2.1 </span>Attributes</a></li><li class="tocline"><a class="tocxref" href="#methods"><span class="secno">3.2.2 </span>Methods</a></li></ul></li><li class="tocline"><a class="tocxref" href="#capturecallback"><span class="secno">3.3 </span><span class="idlType formerLink idlType"><code>CaptureCB</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#methods-1"><span class="secno">3.3.1 </span>Methods</a></li></ul></li><li class="tocline"><a class="tocxref" href="#errorcallback"><span class="secno">3.4 </span><span class="idlType formerLink idlType"><code>CaptureErrorCB</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#methods-2"><span class="secno">3.4.1 </span>Methods</a></li></ul></li><li class="tocline"><a class="tocxref" href="#captureerror"><span class="secno">3.5 </span><span class="idlType formerLink idlType"><code>CaptureError</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes-2"><span class="secno">3.5.1 </span>Attributes</a></li><li class="tocline"><a class="tocxref" href="#constants"><span class="secno">3.5.2 </span>Constants</a></li></ul></li><li class="tocline"><a class="tocxref" href="#captureimageoptions"><span class="secno">3.6 </span><span class="idlType formerLink idlType"><code>CaptureImageOptions</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes-3"><span class="secno">3.6.1 </span>Attributes</a></li></ul></li><li class="tocline"><a class="tocxref" href="#capturevideooptions"><span class="secno">3.7 </span><span class="idlType formerLink idlType"><code>CaptureVideoOptions</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes-4"><span class="secno">3.7.1 </span>Attributes</a></li></ul></li><li class="tocline"><a class="tocxref" href="#captureaudiooptions"><span class="secno">3.8 </span><span class="idlType formerLink idlType"><code>CaptureAudioOptions</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#attributes-5"><span class="secno">3.8.1 </span>Attributes</a></li></ul></li><li class="tocline"><a class="tocxref" href="#pendingoperation"><span class="secno">3.9 </span><span class="idlType formerLink idlType"><code>PendingOperation</code></span> interface</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#methods-3"><span class="secno">3.9.1 </span>Methods</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#captured-files"><span class="secno">4. </span>Captured Files</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#lifetime"><span class="secno">4.1 </span>Lifetime</a></li></ul></li><li class="tocline"><a class="tocxref" href="#related"><span class="secno">A. </span>Related documents</a></li><li class="tocline"><a class="tocxref" href="#ack"><span class="secno">B. </span>Acknowledgements</a></li><li class="tocline"><a class="tocxref" href="#references"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#normative-references"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a class="tocxref" href="#informative-references"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></div>
<div class="section" id="introduction">
<!--OddPage--><h2><span class="secno">1. </span>Introduction</h2>
<p>The Capture API defines a high-level interface for accessing the
microphone and camera of a hosting device. It completes the HTML Form Based Media Capturing specification [<cite><a href="#bib-HTMLMEDIACAPTURE" rel="biblioentry" class="bibref">HTMLMEDIACAPTURE</a></cite>] with a programmatic access to start a parametrized capture process.</p>
<div class="section" id="examples">
<h3><span class="secno">1.1 </span>Usage Examples</h3>
<p>The following code extracts illustrate how to work with a
camera service in the hosting device:</p>
<div>
<p>Launching a camera application and retrieving the
pictures taken. </p>
<pre class="example sh_javascript_dom sh_sourceCode"><span class="sh_keyword">function</span> <span class="sh_function">success</span><span class="sh_symbol">(</span>data<span class="sh_symbol">)</span> <span class="sh_cbracket">{</span>
<span class="sh_keyword">var</span> container <span class="sh_symbol">=</span> <span class="sh_predef_var">document</span><span class="sh_symbol">.</span><span class="sh_function">createElement</span><span class="sh_symbol">(</span><span class="sh_string">"div"</span><span class="sh_symbol">);</span>
<span class="sh_keyword">for</span> <span class="sh_symbol">(</span><span class="sh_keyword">var</span> i <span class="sh_keyword">in</span> data<span class="sh_symbol">)</span> <span class="sh_cbracket">{</span>
<span class="sh_keyword">var</span> img <span class="sh_symbol">=</span> <span class="sh_predef_var">document</span><span class="sh_symbol">.</span><span class="sh_function">createElement</span><span class="sh_symbol">(</span><span class="sh_string">"img"</span><span class="sh_symbol">);</span>
img<span class="sh_symbol">.</span>src <span class="sh_symbol">=</span> data<span class="sh_symbol">[</span>i<span class="sh_symbol">].</span>url<span class="sh_symbol">;</span>
container<span class="sh_symbol">.</span><span class="sh_function">appendChild</span><span class="sh_symbol">(</span>img<span class="sh_symbol">);</span>
<span class="sh_cbracket">}</span>
<span class="sh_predef_var">document</span><span class="sh_symbol">.</span>body<span class="sh_symbol">.</span><span class="sh_function">appendChild</span><span class="sh_symbol">(</span>container<span class="sh_symbol">);</span>
<span class="sh_cbracket">}</span>
<span class="sh_keyword">function</span> <span class="sh_function">error</span><span class="sh_symbol">(</span>err<span class="sh_symbol">)</span> <span class="sh_cbracket">{</span>
<span class="sh_keyword">if</span> <span class="sh_symbol">(</span>err<span class="sh_symbol">.</span>code <span class="sh_symbol">===</span> err<span class="sh_symbol">.</span>CAPTURE_INTERNAL_ERR<span class="sh_symbol">)</span> <span class="sh_cbracket">{</span>
<span class="sh_predef_func">alert</span><span class="sh_symbol">(</span><span class="sh_string">"The capture failed due to an internal error."</span><span class="sh_symbol">);</span>
<span class="sh_cbracket">}</span>
<span class="sh_keyword">else</span> <span class="sh_cbracket">{</span>
<span class="sh_predef_func">alert</span><span class="sh_symbol">(</span><span class="sh_string">"Other error occured."</span><span class="sh_symbol">);</span>
<span class="sh_cbracket">}</span>
<span class="sh_cbracket">}</span>
<span class="sh_predef_var">navigator</span><span class="sh_symbol">.</span>device<span class="sh_symbol">.</span>capture<span class="sh_symbol">.</span><span class="sh_function">captureImage</span><span class="sh_symbol">(</span>success<span class="sh_symbol">,</span> error<span class="sh_symbol">,</span> <span class="sh_cbracket">{</span> limit<span class="sh_symbol">:</span> <span class="sh_number">1</span> <span class="sh_cbracket">}</span><span class="sh_symbol">);</span></pre>
</div>
<div>
<p>Example of retrieving image sizes and formats supported by hosting
device camera.</p>
<pre class="example sh_javascript_dom sh_sourceCode"><span class="sh_keyword">var</span> summary<span class="sh_symbol">;</span>
formats <span class="sh_symbol">=</span> <span class="sh_predef_var">navigator</span><span class="sh_symbol">.</span>device<span class="sh_symbol">.</span>capture<span class="sh_symbol">.</span>supportedImageFormats<span class="sh_symbol">;</span>
<span class="sh_keyword">for</span> <span class="sh_symbol">(</span><span class="sh_keyword">var</span> key <span class="sh_keyword">in</span> formats<span class="sh_symbol">)</span> <span class="sh_cbracket">{</span>
summary <span class="sh_symbol">+=</span> key <span class="sh_symbol">+</span> <span class="sh_string">": "</span> <span class="sh_symbol">+</span> formats<span class="sh_symbol">[</span>key<span class="sh_symbol">]</span> <span class="sh_symbol">+</span> <span class="sh_string">"</span><span class="sh_specialchar">\n</span><span class="sh_string">"</span><span class="sh_symbol">;</span>
<span class="sh_cbracket">}</span>
<span class="sh_predef_func">alert</span><span class="sh_symbol">(</span>summary<span class="sh_symbol">);</span></pre>
</div>
</div>
<div class="section" id="terminology">
<h3><span class="secno">1.2 </span>Terminology</h3>
The terms <b>camera application</b>, <b>camcorder
application</b>, and <b>audio capture application</b> are used
to refer piece of an interactive software implemented either by
the user agent or the underlying operating environment that
carry out the actual capture operation.
</div>
</div>
<div class="section" id="security">
<!--OddPage--><h2><span class="secno">2. </span>Security and Privacy Considerations</h2>
<p class="note">
<strong>The overall architecture for addressing privacy in DAP is still
under construction. As it is finalized, there may be changes made to
this API to reflect requirements or support for privacy-related
functionality.</strong>
</p>
<p>The API defined in this specification launches the capture
application which allows the user to take pictures, record voice or
record video and provides a handle to the content. This information
can potentially compromise user privacy and a conforming
implementation of this specification <em title="must" class="rfc2119">must</em> provide a mechanism that
protects the user's privacy and this mechanism should ensure that such
operations <em title="must not" class="rfc2119">must not</em> happen without user consent.</p>
<h3 id="privacy-considerations-for-implementers-of-capture-api">Privacy considerations for implementers of Capture API</h3>
<p>A conforming implementation of this specification <em title="must" class="rfc2119">must</em> provide a
mechanism that protects the user's privacy and this mechanism <em title="should" class="rfc2119">should</em>
ensure that privacy information is not revealed without user's
informed consent.</p>
<p class="note">
<strong>Note that there is a minimization issue with EXIF headers.
Implementations are assumed to avoid embeding information in the EXIF header which
could be used for non-intended purposes (such as geolocation or device id).
</strong>
</p>
</div>
<div class="section" id="api">
<!--OddPage--><h2><span class="secno">3. </span>API Description</h2>
<div class="section" id="devicecapture-interface">
<h3><span class="secno">3.1 </span><a class="idlType" href="#idl-def-DeviceCapture"><code>DeviceCapture</code></a> interface</h3>
<p>The <a href="#devicecapture-interface"><code>DeviceCapture</code></a> interface is exposed on the <code>navigator.device</code> object, as defined in [<cite><a href="#bib-CORE-DEVICE" rel="biblioentry" class="bibref">CORE-DEVICE</a></cite>].
</p>
<pre class="idl"><span class="idlImplements"><a>Device</a> implements <a class="idlType" href="#idl-def-DeviceCapture"><code>DeviceCapture</code></a>;</span></pre><div class="idlImplementsDesc">
</div>
<pre class="idl"><span class="idlInterface" id="idl-def-DeviceCapture">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">DeviceCapture</span> {
<span class="idlAttribute"> readonly attribute <span class="idlAttrType"><a class="idlType" href="#idl-def-Capture"><code>Capture</code></a></span> <span class="idlAttrName"><a href="#widl-DeviceCapture-capture">capture</a></span>;</span>
};</span>
</pre><div class="section" id="attributes"><h4><span class="secno">3.1.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-DeviceCapture-capture"><code>capture</code> of type <span class="idlAttrType"><a class="idlType" href="#idl-def-Capture"><code>Capture</code></a></span>, readonly</dt><dd>
The root node from which the capture functionality can be accessed.
<div><em>No exceptions.</em></div></dd></dl></div>
</div>
<div class="section" id="capture-interface">
<h3><span class="secno">3.2 </span><a class="idlType" href="#idl-def-Capture"><code>Capture</code></a> interface</h3>
<p>The <a href="#capture-interface"><code>Capture</code></a> interface exposes an interface to the camera and microphone of the hosting device.
</p>
<p class="note">
The MediaFileData Interface contains a duration attribute. What does it mean here? Is it the max recording length?.
</p>
<p class="note">
Should the default audio, video, and image codec be defined that all implementations need to support? If yes, which codecs should be selected?
</p>
<p class="note">
Duration and bitrate attributes of MediaFileData object make no sense in case of supportedImageFormats. Use of more well suited interface to be considered.
</p>
<pre class="idl"><span class="idlInterface" id="idl-def-Capture">[<span class="extAttr">Supplemental, NoInterfaceObject</span>]
interface <span class="idlInterfaceID">Capture</span> {
<span class="idlAttribute"> readonly attribute <span class="idlAttrType"><a>MediaFileData</a>[]</span> <span class="idlAttrName"><a href="#widl-Capture-supportedImageFormats">supportedImageFormats</a></span>;</span>
<span class="idlAttribute"> readonly attribute <span class="idlAttrType"><a>MediaFileData</a>[]</span> <span class="idlAttrName"><a href="#widl-Capture-supportedVideoFormats">supportedVideoFormats</a></span>;</span>
<span class="idlAttribute"> readonly attribute <span class="idlAttrType"><a>MediaFileData</a>[]</span> <span class="idlAttrName"><a href="#widl-Capture-supportedAudioFormats">supportedAudioFormats</a></span>;</span>
<span class="idlMethod"> <span class="idlMethType"><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></span> <span class="idlMethName"><a href="#widl-Capture-captureImage">captureImage</a></span> (<span class="idlParam">in <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></span> <span class="idlParamName">successCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></span> <span class="idlParamName">errorCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureImageOptions"><code>CaptureImageOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
<span class="idlMethod"> <span class="idlMethType"><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></span> <span class="idlMethName"><a href="#widl-Capture-captureVideo">captureVideo</a></span> (<span class="idlParam">in <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></span> <span class="idlParamName">successCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></span> <span class="idlParamName">errorCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureVideoOptions"><code>CaptureVideoOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
<span class="idlMethod"> <span class="idlMethType"><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></span> <span class="idlMethName"><a href="#widl-Capture-captureAudio">captureAudio</a></span> (<span class="idlParam">in <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></span> <span class="idlParamName">successCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></span> <span class="idlParamName">errorCB</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureAudioOptions"><code>CaptureAudioOptions</code></a></span> <span class="idlParamName">options</span></span>);</span>
};</span>
</pre><div class="section" id="attributes-1"><h4><span class="secno">3.2.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-Capture-supportedAudioFormats"><code>supportedAudioFormats</code> of type array of <span class="idlAttrType"><a>MediaFileData</a></span>, readonly</dt><dd>An array of MediaFileData [<cite><a href="#bib-HTMLMEDIACAPTURE" rel="biblioentry" class="bibref">HTMLMEDIACAPTURE</a></cite>] objects which contains audio
formats supported by the hosting device microphone.<div><em>No exceptions.</em></div></dd><dt id="widl-Capture-supportedImageFormats"><code>supportedImageFormats</code> of type array of <span class="idlAttrType"><a>MediaFileData</a></span>, readonly</dt><dd>An array of MediaFileData [<cite><a href="#bib-HTMLMEDIACAPTURE" rel="biblioentry" class="bibref">HTMLMEDIACAPTURE</a></cite>] objects which contains image sizes
and formats supported by the hosting device camera.<div><em>No exceptions.</em></div></dd><dt id="widl-Capture-supportedVideoFormats"><code>supportedVideoFormats</code> of type array of <span class="idlAttrType"><a>MediaFileData</a></span>, readonly</dt><dd>An array of MediaFileData [<cite><a href="#bib-HTMLMEDIACAPTURE" rel="biblioentry" class="bibref">HTMLMEDIACAPTURE</a></cite>] objects which contains video
resolutions and formats supported by the hosting device
camera.<div><em>No exceptions.</em></div></dd></dl></div><div class="section" id="methods"><h4><span class="secno">3.2.2 </span>Methods</h4><dl class="methods"><dt id="widl-Capture-captureAudio"><code>captureAudio</code></dt><dd><p>Launch audio recorder application for
recording audio clip(s).</p>
<p>This method takes two or three arguments. When called, it
immediately returns a <a href="#pendingoperation">
<code>PendingOperation</code></a> object and then asynchronously
start a <em>capture audio</em> process defined as follows:</p>
<p></p>
<ol>
<li>Start audio recorder application. Allow end user to record
audio clip(s) and return.</li>
<li>If successful, invoke the associated <code>successCB</code>
with a <code>FileList</code> [<cite><a href="#bib-FILE-API" rel="biblioentry" class="bibref">FILE-API</a></cite>]
argument. If the attempt fails, and the method was invoked with a
non-null <code>errorCallback</code> argument, this method must invoke
the <code>errorCallback</code> with a <a href="#captureerror"><code>CaptureError</code></a> object as
an argument.</li>
<li>If a <code>CaptureAudioOptions</code> parameter was present,
and its <code>limit</code> attribute was defined,
<code>successCB</code> <em title="must" class="rfc2119">must</em> be invoked after the user has
captured a number of audio clips defined in
<code>limit</code>. If user exited the audio recorder
application prematurely without recording any audio clips, <code>errorCB</code> must be invoked.
</li>
</ol>
<p></p>
<table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">successCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">Function to call when the asynchronous operation completes </td></tr><tr><td class="prmName">errorCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Function to call when the asynchronous operation fails. This
parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr><tr><td class="prmName">options</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureAudioOptions"><code>CaptureAudioOptions</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Audio capture options. This parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></code></div></dd><dt id="widl-Capture-captureImage"><code>captureImage</code></dt><dd><p>Launch camera application for taking image(s).</p>
<p>This method takes two or three arguments. When called, it
immediately returns a <a href="#pendingoperation"><code>PendingOperation</code></a>
object and then asynchronously start a <em>capture image</em>
process defined as follows:</p>
<p></p>
<ol>
<li>Start camera application. Allow end user to take
picture(s).</li>
<li>If successful, invoke the associated <code>successCB</code>
with a <code>FileList</code> [<cite><a href="#bib-FILE-API" rel="biblioentry" class="bibref">FILE-API</a></cite>]
argument. If the attempt fails, and the method was invoked with a
non-null <code>errorCallback</code> argument, this method must
invoke the <code>errorCallback</code> with a <a href="#captureerror"><code>CaptureError</code></a> object
as an argument.</li>
<li>If a <code>CaptureImageOptions</code> parameter was present,
and its <code>limit</code> attribute was defined,
<code>successCB</code> <em title="must" class="rfc2119">must</em> be invoked after the user has
captured a number of images defined in <code>limit</code>. If
user exited the camera application without capturing any images,
<code>errorCB</code> must be invoked.</li> </ol>
<p></p>
<table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">successCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">Function to call when the asynchronous operation completes </td></tr><tr><td class="prmName">errorCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Function to call when the asynchronous operation
fails. This parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr><tr><td class="prmName">options</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureImageOptions"><code>CaptureImageOptions</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Image capture options. This parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></code></div></dd><dt id="widl-Capture-captureVideo"><code>captureVideo</code></dt><dd>
<p>Launch device camera application for recording
video(s).</p>
<p>This method takes three or four arguments. When called, it
immediately returns a <a href="#pendingoperation"><code>PendingOperation</code></a>
object and then asynchronously start a <em>capture video</em> process
defined as follows:</p>
<p></p>
<ol>
<li>Start camcorder application. Allow end user to
take video(s) and return. </li><li>If successful, invoke the
associated <code>successCB</code> with a <code>FileList</code>
[<cite><a href="#bib-FILE-API" rel="biblioentry" class="bibref">FILE-API</a></cite>] argument. If
the attempt fails, and the method was invoked with a non-null
<code>errorCallback</code> argument, this method must invoke the
<code>errorCallback</code> with a <a href="#captureerror"><code>CaptureError</code></a> object as
an argument.</li>
<li>If a <code>CaptureVideoOptions</code> parameter was present, and
its <code>limit</code> attribute was defined,
<code>successCB</code> <em title="must" class="rfc2119">must</em> be invoked after the user has
captured a number of video clips defined in
<code>limit</code>. If user exited the camera
application without capturing any videos, <code>errorCB</code> must be invoked.</li>
<li>If a <code>CaptureVideoOptions</code> parameter was present,
and its <code>duration</code> attribute was defined,
<code>successCB</code> <em title="must" class="rfc2119">must</em> be invoked after the video has
been captured for the number of seconds defined in
<code>duration</code>. If user exited the camcorder
application without capturing any video clips, <code>errorCB</code> must be invoked.
</li>
</ol>
<p></p>
<table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">successCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">Function to call when the asynchronous operation completes </td></tr><tr><td class="prmName">errorCB</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Function to call when the asynchronous operation fails. This
parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr><tr><td class="prmName">options</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureVideoOptions"><code>CaptureVideoOptions</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptTrue">✔</td><td class="prmDesc">Image capture options. This parameter is <em title="optional" class="rfc2119">optional</em>.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a></code></div></dd></dl></div>
</div>
<div class="section" id="capturecallback"><h3><span class="secno">3.3 </span><a class="idlType" href="#idl-def-CaptureCB"><code>CaptureCB</code></a> interface</h3>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureCB">[<span class="extAttr">Callback=FunctionOnly, NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureCB</span> {
<span class="idlMethod"> <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-CaptureCB-onSuccess">onSuccess</a></span> (<span class="idlParam">in <span class="idlParamType"><a>FileList</a></span> <span class="idlParamName">capturedMedia</span></span>);</span>
};</span>
</pre><div class="section" id="methods-1"><h4><span class="secno">3.3.1 </span>Methods</h4><dl class="methods"><dt id="widl-CaptureCB-onSuccess"><code>onSuccess</code></dt><dd>
<table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">capturedMedia</td><td class="prmType"><code><a>FileList</a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">
Sequence of Files [<cite><a href="#bib-FILE-API" rel="biblioentry" class="bibref">FILE-API</a></cite>] (implementing the MediaFile [<cite><a href="#bib-HTMLMEDIACAPTURE" rel="biblioentry" class="bibref">HTMLMEDIACAPTURE</a></cite>] interface) successfully captured by the device
</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>void</a></code></div></dd></dl></div>
</div>
<div class="section" id="errorcallback"><h3><span class="secno">3.4 </span><a class="idlType" href="#idl-def-CaptureErrorCB"><code>CaptureErrorCB</code></a> interface</h3>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureErrorCB">[<span class="extAttr">Callback=FunctionOnly, NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureErrorCB</span> {
<span class="idlMethod"> <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-CaptureErrorCB-onError">onError</a></span> (<span class="idlParam">in <span class="idlParamType"><a class="idlType" href="#idl-def-CaptureError"><code>CaptureError</code></a></span> <span class="idlParamName">error</span></span>);</span>
};</span>
</pre><div class="section" id="methods-2"><h4><span class="secno">3.4.1 </span>Methods</h4><dl class="methods"><dt id="widl-CaptureErrorCB-onError"><code>onError</code></dt><dd>
<table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">error</td><td class="prmType"><code><a class="idlType" href="#idl-def-CaptureError"><code>CaptureError</code></a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">The error
object of an unsuccessful capture asynchronous operation. </td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>void</a></code></div></dd></dl></div>
</div>
<div class="section" id="captureerror"><h3><span class="secno">3.5 </span><a class="idlType" href="#idl-def-CaptureError"><code>CaptureError</code></a> interface</h3>
<p>The <a class="idlType" href="#idl-def-CaptureError"><code>CaptureError</code></a> interface encapsulates all errors in the
Capture API. </p>
<p class="note">More error codes to be defined here. </p>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureError">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureError</span> {
<span class="idlConst"> const <span class="idlConstType"><a>unsigned short</a></span> <span class="idlConstName"><a href="#widl-CaptureError-CAPTURE_INTERNAL_ERR">CAPTURE_INTERNAL_ERR</a></span> = <span class="idlConstValue">0</span>;</span>
<span class="idlConst"> const <span class="idlConstType"><a>unsigned short</a></span> <span class="idlConstName"><a href="#widl-CaptureError-CAPTURE_APPLICATION_BUSY">CAPTURE_APPLICATION_BUSY</a></span> = <span class="idlConstValue">1</span>;</span>
<span class="idlConst"> const <span class="idlConstType"><a>unsigned short</a></span> <span class="idlConstName"><a href="#widl-CaptureError-CAPTURE_INVALID_ARGUMENT">CAPTURE_INVALID_ARGUMENT</a></span> = <span class="idlConstValue">2</span>;</span>
<span class="idlConst"> const <span class="idlConstType"><a>unsigned short</a></span> <span class="idlConstName"><a href="#widl-CaptureError-CAPTURE_NO_MEDIA_FILES">CAPTURE_NO_MEDIA_FILES</a></span> = <span class="idlConstValue">3</span>;</span>
<span class="idlAttribute"> readonly attribute <span class="idlAttrType"><a>unsigned short</a></span> <span class="idlAttrName"><a href="#widl-CaptureError-code">code</a></span>;</span>
};</span>
</pre><div class="section" id="attributes-2"><h4><span class="secno">3.5.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-CaptureError-code"><code>code</code> of type <span class="idlAttrType"><a>unsigned short</a></span>, readonly</dt><dd>An error code assigned by an implementation when an error has
occurred in Capture API processing.<div><em>No exceptions.</em></div></dd></dl></div><div class="section" id="constants"><h4><span class="secno">3.5.2 </span>Constants</h4><dl class="constants"><dt id="widl-CaptureError-CAPTURE_APPLICATION_BUSY"><code>CAPTURE_APPLICATION_BUSY</code> of type <span class="idlConstType"><a>unsigned short</a></span></dt><dd>Camera application or audio capture application is currently serving other capture request.</dd><dt id="widl-CaptureError-CAPTURE_INTERNAL_ERR"><code>CAPTURE_INTERNAL_ERR</code> of type <span class="idlConstType"><a>unsigned short</a></span></dt><dd>Camera or microphone failed to capture image or sound. </dd><dt id="widl-CaptureError-CAPTURE_INVALID_ARGUMENT"><code>CAPTURE_INVALID_ARGUMENT</code> of type <span class="idlConstType"><a>unsigned short</a></span></dt><dd>Invalid use of the API (e.g. limit parameter has value less than one).</dd><dt id="widl-CaptureError-CAPTURE_NO_MEDIA_FILES"><code>CAPTURE_NO_MEDIA_FILES</code> of type <span class="idlConstType"><a>unsigned short</a></span></dt><dd>User exited camera application or audio capture application before capturing anything.</dd></dl></div>
</div>
<div class="section" id="captureimageoptions"><h3><span class="secno">3.6 </span><a class="idlType" href="#idl-def-CaptureImageOptions"><code>CaptureImageOptions</code></a> interface</h3>
<p>The <a class="idlType" href="#idl-def-CaptureImageOptions"><code>CaptureImageOptions</code></a> interface encapsulates all image
capture operation configuration options.</p>
<p class="note">Additional attributes proposed: <code>width</code>
and <code>height</code>.</p>
<p class="note">We might want to add <code>format</code> to give author control
over the capture format.</p>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureImageOptions">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureImageOptions</span> {
<span class="idlAttribute"> attribute <span class="idlAttrType"><a>unsigned long</a></span> <span class="idlAttrName"><a href="#widl-CaptureImageOptions-limit">limit</a></span>;</span>
};</span>
</pre><div class="section" id="attributes-3"><h4><span class="secno">3.6.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-CaptureImageOptions-limit"><code>limit</code> of type <span class="idlAttrType"><a>unsigned long</a></span></dt><dd>Upper limit of images user can take. Value <em title="must" class="rfc2119">must</em> be equal or greater than one.<div><em>No exceptions.</em></div></dd></dl></div>
</div>
<div class="section" id="capturevideooptions"><h3><span class="secno">3.7 </span><a class="idlType" href="#idl-def-CaptureVideoOptions"><code>CaptureVideoOptions</code></a> interface</h3>
<p class="note">We might want to add <code>format</code> to give author control
over the capture format.</p>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureVideoOptions">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureVideoOptions</span> {
<span class="idlAttribute"> attribute <span class="idlAttrType"><a>unsigned long</a></span> <span class="idlAttrName"><a href="#widl-CaptureVideoOptions-limit">limit</a></span>;</span>
<span class="idlAttribute"> attribute <span class="idlAttrType"><a>float</a></span> <span class="idlAttrName"><a href="#widl-CaptureVideoOptions-duration">duration</a></span>;</span>
};</span>
</pre><div class="section" id="attributes-4"><h4><span class="secno">3.7.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-CaptureVideoOptions-duration"><code>duration</code> of type <span class="idlAttrType"><a>float</a></span></dt><dd>Maximum duration of a single video clip in seconds.<div><em>No exceptions.</em></div></dd><dt id="widl-CaptureVideoOptions-limit"><code>limit</code> of type <span class="idlAttrType"><a>unsigned long</a></span></dt><dd>Upper limit of videos user can record. Value <em title="must" class="rfc2119">must</em> be equal or greater than one<div><em>No exceptions.</em></div></dd></dl></div>
</div>
<div class="section" id="captureaudiooptions"><h3><span class="secno">3.8 </span><a class="idlType" href="#idl-def-CaptureAudioOptions"><code>CaptureAudioOptions</code></a> interface</h3>
<p class="note">Additional attributes proposed: <code>duration</code>.</p>
<p class="note">We might want to add <code>format</code> to give author control
over the capture format.</p>
<pre class="idl"><span class="idlInterface" id="idl-def-CaptureAudioOptions">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">CaptureAudioOptions</span> {
<span class="idlAttribute"> attribute <span class="idlAttrType"><a>unsigned long</a></span> <span class="idlAttrName"><a href="#widl-CaptureAudioOptions-limit">limit</a></span>;</span>
};</span>
</pre><div class="section" id="attributes-5"><h4><span class="secno">3.8.1 </span>Attributes</h4><dl class="attributes"><dt id="widl-CaptureAudioOptions-limit"><code>limit</code> of type <span class="idlAttrType"><a>unsigned long</a></span></dt><dd>Upper limit of sound clips user can record. Value <em title="must" class="rfc2119">must</em> be equal or greater than one<div><em>No exceptions.</em></div></dd></dl></div>
</div>
<div class="section" id="pendingoperation"><h3><span class="secno">3.9 </span><a class="idlType" href="#idl-def-PendingOperation"><code>PendingOperation</code></a> interface</h3>
<p class="note">This may be a general interface for use throughout
all APIs. Included here for now for completion.</p>
<pre class="idl"><span class="idlInterface" id="idl-def-PendingOperation">[<span class="extAttr">NoInterfaceObject</span>]
interface <span class="idlInterfaceID">PendingOperation</span> {
<span class="idlMethod"> <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-PendingOperation-cancel">cancel</a></span> ();</span>
};</span>
</pre><div class="section" id="methods-3"><h4><span class="secno">3.9.1 </span>Methods</h4><dl class="methods"><dt id="widl-PendingOperation-cancel"><code>cancel</code></dt><dd>Cancel the pending asynchronous operation and close the native recording application automatically. No success or error callback for the pending operation will be invoked. Possible incomplete set of capture files will be deleted.
<p class="note">
The effect of cancel method is currently under discussion in the working group. Is it necessary to delete files? Which callbacks (if any) should be invoked?
</p>
<div><em>No parameters.</em></div><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>void</a></code></div></dd></dl></div>
</div>
</div>
<div class="section" id="captured-files">
<!--OddPage--><h2><span class="secno">4. </span>Captured Files</h2>
<div class="section" id="lifetime">
<h3><span class="secno">4.1 </span>Lifetime</h3>
<p>User agents <em title="should" class="rfc2119">should</em> discard the captured files only after the <u>top-level browsing context</u> [<cite><a href="#bib-HTML5" rel="biblioentry" class="bibref">HTML5</a></cite>] related to the script is destroyed. In a special cases where the UA detects limited storage space, files <em title="may" class="rfc2119">may</em> be deleted earlier.</p>
</div>
</div>
<div class="appendix section" id="related">
<!--OddPage--><h2><span class="secno">A. </span>Related documents</h2>
<p>The API described in this document took inspiration from the following documents:</p>
<ul>
<li><a href="http://code.google.com/p/gears/wiki/CameraAPI">Google Camera API</a>
</li><li><a href="http://bondi.omtp.org/1.0/apis/camera.html">BONDI 1.1 camera API</a>
</li><li><a href="http://lists.w3.org/Archives/Public/public-device-apis/2009Apr/att-0001/camera.html">Nokia Camera API</a>
</li></ul>
</div>
<div class="appendix section" id="ack">
<!--OddPage--><h2><span class="secno">B. </span>Acknowledgements</h2>
<p>Many thanks to Google, Nokia, and OMTP BONDI who provided the
initial input into this specification.
</p>
</div>
<div class="appendix section" id="references"><!--OddPage--><h2><span class="secno">C. </span>References</h2><div class="section" id="normative-references"><h3><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography"><dt id="bib-CORE-DEVICE">[CORE-DEVICE]</dt><dd>Robin Berjon. <a href="http://dev.w3.org/2009/dap/device/"><cite>Core Device Interfaces.</cite></a> 02 December 2009. W3C Editor's Draft. (Work in progress.) URL: <a href="http://dev.w3.org/2009/dap/device/">http://dev.w3.org/2009/dap/device/</a>
</dd><dt id="bib-FILE-API">[FILE-API]</dt><dd>Arun Ranganathan. <a href="http://www.w3.org/TR/2009/WD-FileAPI-20091117/"><cite>File API.</cite></a> 17 November 2009. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2009/WD-FileAPI-20091117/">http://www.w3.org/TR/2009/WD-FileAPI-20091117/</a>
</dd><dt id="bib-HTMLMEDIACAPTURE">[HTMLMEDIACAPTURE]</dt><dd>Ilkka Oksanen, Dominique Hazaël-Massieux, eds. <a href="http://www.w3.org/TR/2010/WD-html-media-capture-20100720/"><cite>The Capture API</cite></a>, 20 July 2010, W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2010/WD-html-media-capture-20100720/">http://www.w3.org/TR/2010/WD-html-media-capture-20100720/</a>
</dd></dl></div><div class="section" id="informative-references"><h3><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography"><dt id="bib-HTML5">[HTML5]</dt><dd>Ian Hickson; David Hyatt. <a href="http://www.w3.org/TR/2010/WD-html5-20100304/"><cite>HTML 5.</cite></a> 4 March 2010. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2010/WD-html5-20100304/">http://www.w3.org/TR/2010/WD-html5-20100304/</a>
</dd></dl></div></div></body></html>