---
title: MediaDevices
slug: Web/API/MediaDevices
tags:
  - API
  - Experimental
  - Interface
  - Media
  - MediaDevices
  - NeedsTranslation
  - TopicStub
  - WebRTC
  - 媒体
  - 媒体流
  - 媒体设备
translation_of: Web/API/MediaDevices
---
<div>{{APIRef("Media Capture and Streams")}}</div>

<p><span class="seoSummary"><strong><code>MediaDevices</code></strong> 接口提供访问连接媒体输入的设备，如照相机和麦克风，以及屏幕共享等。它可以使你取得任何硬件资源的媒体数据。</span></p>

<h2 id="属性">属性</h2>

<p><em>从父类{{domxref("EventTarget")}}中继承的属性.</em></p>

<h2 id="事件">事件</h2>

<dl>
 <dt>{{domxref("MediaDevices.devicechange_event", "devicechange")}}</dt>
 <dd>返回 {{event("devicechange")}} 事件类型的事件处理程序。<br>
 也可通过 {{domxref("MediaDevices/ondevicechange", "ondevicechange")}} 访问</dd>
</dl>

<h2 id="方法">方法</h2>

<p><em>从其父项继承方法 {{domxref("EventTarget")}}.</em></p>

<dl>
 <dt>{{ domxref("MediaDevices.enumerateDevices()") }}</dt>
 <dd>获取有关系统中可用的媒体输入和输出设备的一系列信息。</dd>
 <dt>{{domxref("MediaDevices.getSupportedConstraints", "getSupportedConstraints()")}}</dt>
 <dd>返回一个符合 {{domxref("MediaTrackSupportedConstraints")}} 的对象。该对象指明了 {{domxref("MediaStreamTrack")}} 接口支持的可约束的属性。查看 {{SectionOnPage("/en-US/docs/Web/API/Media_Streams_API", "Capabilities and constraints")}} 去了解更多相关信息。</dd>
 <dt>{{domxref("MediaDevices.getDisplayMedia", "getDisplayMedia()")}}</dt>
 <dd>提示用户选择显示器或显示器的一部分（例如窗口）以捕获为{{domxref("MediaStream")}} 以便共享或记录。返回解析为MediaStream的Promise。</dd>
 <dt>{{ domxref("MediaDevices.getUserMedia()") }}</dt>
 <dd>在用户通过提示允许的情况下，打开系统上的相机或屏幕共享和/或麦克风，并提供 {{domxref("MediaStream")}} 包含视频轨道和/或音频轨道的输入。</dd>
 <dt></dt>
</dl>

<h2 id="示例">示例</h2>

<pre class="brush:js notranslate">'use strict';

// Put variables in global scope to make them available to the browser console.
var video = document.querySelector('video');
var constraints = window.constraints = {
  audio: false,
  video: true
};
var errorElement = document.querySelector('#errorMsg');

navigator.mediaDevices.getUserMedia(constraints)
.then(function(stream) {
  var videoTracks = stream.getVideoTracks();
  console.log('Got stream with constraints:', constraints);
  console.log('Using video device: ' + videoTracks[0].label);
  stream.onended = function() {
    console.log('Stream ended');
  };
  window.stream = stream; // make variable available to browser console
  video.srcObject = stream;
})
.catch(function(error) {
  if (error.name === 'ConstraintNotSatisfiedError') {
    errorMsg('The resolution ' + constraints.video.width.exact + 'x' +
        constraints.video.width.exact + ' px is not supported by your device.');
  } else if (error.name === 'PermissionDeniedError') {
    errorMsg('Permissions have not been granted to use your camera and ' +
      'microphone, you need to allow the page access to your devices in ' +
      'order for the demo to work.');
  }
  errorMsg('getUserMedia error: ' + error.name, error);
});

function errorMsg(msg, error) {
  errorElement.innerHTML += '&lt;p&gt;' + msg + '&lt;/p&gt;';
  if (typeof error !== 'undefined') {
    console.error(error);
  }
}</pre>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">规范</th>
   <th scope="col">状态</th>
   <th scope="col">评论</th>
  </tr>
  <tr>
   <td>{{SpecName('Media Capture', '#mediadevices', 'MediaDevices')}}</td>
   <td>{{Spec2('Media Capture')}}</td>
   <td>初始定义</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>



<p>{{Compat("api.MediaDevices")}}</p>

<h2 id="参见">参见</h2>

<ul>
 <li><a href="/zh-CN/docs/Web/API/Media_Streams_API">Media Capture and Streams API</a>: The API this interface is part of.</li>
 <li><a href="/zh-CN/docs/Web/API/Screen_Capture_API">Screen Capture API</a>: The API defining the {{domxref("MediaDevices.getDisplayMedia", "getDisplayMedia()")}} method.</li>
 <li><a href="/zh-CN/docs/Web/API/WebRTC_API">WebRTC API</a></li>
 <li>{{domxref("Navigator.mediaDevices")}}: Returns a reference to a <code>MediaDevices</code> object that can be used to access devices.</li>
 <li><a href="https://github.com/chrisjohndigital/CameraCaptureJS">CameraCaptureJS:</a> HTML5 video capture and playback using <code>MediaDevices</code> and the MediaStream Recording API (<a href="https://github.com/chrisjohndigital/CameraCaptureJS">source on GitHub</a>)</li>
 <li><a href="https://github.com/chrisjohndigital/OpenLang">OpenLang</a>: HTML5 video language lab web application using <code>MediaDevices</code> and the MediaStream Recording API for video recording (<a href="https://github.com/chrisjohndigital/OpenLang">source on GitHub</a>)</li>
</ul>