HTMLMediaElement

HTML媒体元素接口在属性和方法中添加了 HTML元素来支持基础的媒体相关的能力，就像audio和video一样。HTML 视频元素和 HTML 音频元素元素都继承自此接口。
 

特性

从父级元素 HTML 元素继承属性

名称 类型 描述
audioTracks AudioTrackList

表示在该元素中包含的AudioTrack对象列表
autoplay Boolean

表示autoplay的HTML属性，表明在视频加载可用时是否不中断地自动播放资源
buffered 只读 TimeRanges The ranges of the media source that the browser has buffered (if any) at the moment the buffered property is accessed. The returned TimeRanges object is normalized.
controller MediaController

返回当前媒体控制器的MediaController 对象，如果没有连接就返回null
controls Boolean Reflects the controls HTML attribute, indicating whether user interface items for controlling the resource should be displayed.
crossOrigin DOMString The CORS setting for this image element. See CORS settings attributes for details.
currentSrc 只读 DOMString The absolute URL of the chosen media resource (if, for example, the server selects a media file based on the resolution of the user's display), or an empty string if the networkState is EMPTY.
currentTime double 当前播放时间，单位为秒。为其赋值将会使媒体跳到一个新的时间。
defaultMuted Boolean Reflects the muted HTML attribute, indicating whether the media element's audio output should be muted by default. This property has no dynamic effect, to mute and unmute the audio output, use the muted property.
defaultPlaybackRate double The default playback rate for the media. 1.0 is "normal speed," values lower than 1.0 make the media play slower than normal, higher values make it play faster. The value 0.0 is invalid and throws a NOT_SUPPORTED_ERR exception.
duration 只读 double 媒体以秒为单位的总长度时间，如果媒体不可用，则为0.  如果媒体可用，但时间长度未知, 值为NAN. 如果媒体是以stream形式传输并且没有预定长度，则值为Inf。
ended 只读 Boolean Indicates whether the media element has ended playback.
error 只读 MediaError The MediaError object for the most recent error, or null if there has not been an error.
initialTime 只读 double The initial playback position in seconds.
loop Boolean 会映射在HTML标签  loop 属性 , 决定该媒体是否循环播放.
mediaGroup DOMString Reflects the mediagroup HTML attribute, indicating the name of the group of elements it belongs to. A group of media elements shares a common controller.
mediaKeys 只读 MediaKeys Returns a reference to the MediaKeys interface, which is a set of keys that an associated HTMLMediaElement can use for decription of media data during playback.
mozAudioChannelType DOMString Can be used to set the audio channel that the sound coming from an <audio> or <video> element will play in, on a Firefox OS device. See Using the AudioChannels API for more details.
mozChannels 只读 long The number of channels in the audio resource (e.g., 2 for stereo).
mozFrameBufferLength long

Indicates the number of samples that will be returned in the framebuffer of each MozAudioAvailable event. This number is a total for all channels, and by default is set to be the number of channels * 1024 (e.g., 2 channels * 1024 samples = 2048 total).

The mozFrameBufferLength property can be set to a new value, for lower latency, or larger amounts of data, etc. The size given must be a number between 512 and 16384. Using any other size results in an exception being thrown. The best time to set a new length is after the loadedmetadata event fires, when the audio info is known, but before the audio has started or MozAudioAvailable events have begun firing.
mozSampleRate 只读 long The number of samples per second that will be played. For example, 44100 samples per second is the sample rate used by CD audio.
mozSrcObject MediaStream Lets you set or get the Media Stream to be played or being played.
muted Boolean true if the audio is muted, and false otherwise.
networkState unsigned short The current state of fetching the media over the network.
Constant Value Description
NETWORK_EMPTY 0 There is no data yet.  The readyState is also HAVE_NOTHING.
NETWORK_IDLE 1  
NETWORK_LOADING 2 The media is loading.
NETWORK_NO_SOURCE[1] 3  
paused 只读 Boolean Indicates whether the media element is paused.
playbackRate double

The current rate at which the media is being played back. This is used to implement user controls for fast forward, slow motion, and so forth. The normal playback rate is multiplied by this value to obtain the current rate, so a value of 1.0 indicates normal speed.

If the playbackRate is negative, the media is played backwards.
The audio is muted when the media plays backwards or if the fast forward or slow motion is outside a useful range (E.g. Gecko mute the sound outside the range 0.25 and 5.0).

The pitch of the audio is corrected by default and is the same for every speed. Some browsers implement the non-standard preservespitch property to control this.
played 只读 TimeRanges The ranges of the media source that the browser has played, if any.
preload DOMString Reflects the preload HTML attribute, indicating what data should be preloaded, if any. Possible values are: none, metadata, auto. See preload attribute documentation for details.
readyState 只读 unsigned short The readiness state of the media.
Constant Value Description
HAVE_NOTHING 0 No information is available about the media resource.
HAVE_METADATA 1 Enough of the media resource has been retrieved that the metadata attributes are initialized.  Seeking will no longer raise an exception.
HAVE_CURRENT_DATA 2 Data is available for the current playback position, but not enough to actually play more than one frame.
HAVE_FUTURE_DATA 3 Data for the current playback position as well as for at least a little bit of time into the future is available (in other words, at least two frames of video, for example).
HAVE_ENOUGH_DATA 4 Enough data is available—and the download rate is high enough—that the media can be played through to the end without interruption.
seekable 只读 TimeRanges The time ranges that the user is able to seek to, if any.
seeking 只读 Boolean Indicates whether the media is in the process of seeking to a new position.
sinkId 只读 DOMString The unique ID of the audio device delivering output, or an empty string if it is using the user agent default. This ID should be one of the MediaDeviceInfo.deviceid values returned from MediaDevices.enumeratedDevices(), id-multimedia, or id-communications.
src DOMString Reflects the src HTML attribute, containing the URL of a media resource to use. Gecko implements a similar functionality for streams: mozSrcObject.
textTracks TextTrackList Represents the list of TextTrack objects contained in the element.
videoTracks VideoTrackList Represents the list of VideoTrack objects contained in the element.

Note: Yet Gecko supports only single track playback, and the parsing of tracks' metadata is only available for media with Ogg container foramt.
volume double The audio volume, from 0.0 (silent) to 1.0 (loudest).

Methods

Inherits methods from its parent, HTMLElement.

Name & Arguments Return Description
canPlayType(in DOMString type)

DOMString

  • probably: if the specified type appears to be playable.
  • maybe: if it's impossible to tell whether the type is playable without playing it.
  • The empty string: if the specified type definitely cannot be played.
 Determines whether the specified media type can be played back.

Note: Previously canPlayType('video/webm') returned 'probably'. Starting with Gecko 28 (Firefox 28 / Thunderbird 28 / SeaMonkey 2.25 / Firefox OS 1.3), it returns 'maybe'. (bug 884275)
fastSeek(double time) void Directly seek to the given time.
load() void Reset the media element and restart selecting the media resource.  Any pending events are discarded.  How much media data is fetched is still affected by the preload attribute.  This method can be useful for releasing resources after any src attribute and source element descendants have been removed.  Otherwise, it is usually unnecessary to use this method, unless required to rescan source element children after dynamic changes.
mozGetMetadata() Object The mozGetMetadata method returns a javascript object whose properties represent metadata from the playing media resource as {key: value} pairs. A separate copy of the data is returned each time the method is called.
This method must be called after the loadedmetadata event fires.
mozLoadFrom(HTMLMediaElement other) void This method, available only in old Mozilla's implementation, loads data from another media element. This works similarly to load() except that instead of running the normal resource selection algorithm, the source is simply set to the other element's currentSrc.
This is optimized so this element gets access to all of the other element's cached and buffered data; in fact, the two elements share downloaded data so that data downloaded by either element is available to both.
pause() void Pauses the media playback.
play() void Begins playback of the media.
setMediaKeys  Promise Sets the MediaKeys keys to use when decrypting media during playback.
setSinkId Promise Sets the ID of the audio device through which audio output should be rendered if the application is authorized to play out of a given device.

Events

Audio and Video elements can fire quite a few different events.

Specifications

Specification Status Comment
HTML Living Standard
HTMLMediaElement		 Living Standard No change from HTML5
HTML5
HTMLMediaElement		 Recommendation Initial definition.
Unknown
Encrypted Media Extensions		 Unknown Adds MediaKeys,  MediaEncryptedEvent, and setMediaKeys.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 3.5 (1.9.1) [1] 9 ? ?
buffered property (Yes) 4.0 (2.0) 9 ? ?
defaultMuted property (Yes) 11.0 (11.0) ? ? ?
loop property (Yes) 11.0 (11.0) 9 ? ?
seekable property (Yes) 8.0 (8.0) 9 ? ?
defaultPlaybackRate property (Yes) 20.0 (20.0) 9 ? ?
playbackRate property (Yes) 20.0 (20.0) 9 ? ?
preservesPitch property (Yes)webkit 20.0 (20.0)moz 未实现 未实现 未实现
preload property (Yes) 4.0 (2.0) (implemented autobuffer previously) ? ? ?
played property (Yes) 15.0 (15.0) ? ? ?
crossOrigin property (Yes) 12.0 (12.0) as crossorigin
12.0 (12.0)
 		 ? ? ?
mozAudioChannelType property 未实现 未实现 未实现 未实现 未实现
mozChannels, mozFrameBufferLength, mozSampleRate properties 未实现 4.0 (2.0) 未实现 未实现 未实现
mozGetMetadata() 未实现 17.0 (17.0) 未实现 未实现 未实现
mozLoadFrom() 已废弃 Gecko 24 未实现 3.6 (1.9.2) 未实现 未实现 未实现
mozSrcObject property 未实现 18.0 (18.0) 未实现 未实现 未实现
initialTime property ? 9.0 (9.0), removed in 23.0 (23.0) ? ? ?
fastSeek method ? 未实现 bug 778077 ? ? ?
startDate property ? 未实现 bug 847376 ? ? ?
mediaGroup and controller properties ? 未实现 bug 847377 ? ? ?
audioTracks, and videoTracks properties ? 33.0 (33.0), behind the media.track.enabled preference. ? ? ?
textTracks property ? On Nightly, behind the media.webvtt.enabled preference. ? ? ?
sinkId property and setSinkId() method 45.0, behind a flag ? ? ? ?
Feature Android Firefox Mobile (Gecko) Firefox OS (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) ? (Yes) (Yes)
buffered property (Yes) 4.0 (2.0) (Yes) ? ? ?
defaultMuted property (Yes) 11.0 (11.0) (Yes) ? ? ?
loop property (Yes) 11.0 (11.0) (Yes) ? ? ?
seekable property (Yes) 8.0 (8.0) (Yes) ? ? ?
defaultPlaybackRate property (Yes) 20.0 (20.0) (Yes) ? ? ?
playbackRate property (Yes) 20.0 (20.0) (Yes) ? ? ?
preservesPitch property (Yes)webkit 20.0 (20.0)moz (Yes) 未实现 未实现 未实现
preload property (Yes) 4.0 (2.0) (Yes) ? ? ?
played property (Yes) 15.0 (15.0) (Yes) ? ? ?
crossOrigin property (Yes) 12.0 (12.0) as crossorigin
22.0 (22.0)
 		 (Yes) ? ? ?
mozAudiochannelType 未实现 未实现 1.0.1 未实现 未实现 未实现
mozChannels, mozFrameBufferLength, mozSampleRate properties 未实现 4.0 (2.0) (Yes) 未实现 未实现 未实现
mozGetMetadata() 未实现 17.0 (17.0) (Yes) 未实现 未实现 未实现
mozLoadFrom() 未实现 1.0 (1.9.2)
Removed from 24.0 (24)		 (Yes) 未实现 未实现 未实现
mozSrcObject property 未实现 18.0 (18.0) (Yes) 未实现 未实现 未实现
initialTime property ? 9.0 (9.0), removed in 23.0 (23.0) (Yes) ? ? ?
fastSeek method ? 未实现 bug 778077 (Yes) ? ? ?
startDate property ? 未实现 bug 847376 (Yes) ? ? ?
mediaGroup and controller properties ? 未实现 bug 847377 (Yes) ? ? ?
audioTracks, and videoTracks properties ? 33.0 (33.0), behind the media.track.enabled preference. (Yes) ? ? ?
textTracks property ? On Nightly, behind the media.webvtt.enabled preference. (Yes) ? ? ?
sinkId property and setSinkId() method ? ? ? ? ? ?

[1] The NETWORK_LOADED state was removed to align with the HTML spec in Gecko 2.0 (Firefox 4).

See also

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