MediaStream 录制 API
，有时简称为
Media Recording API
或
MediaRecorder API
，密切隶属于
Media Capture and Streams API
和
WebRTC API
。MediaStream Recording API 使捕获生成数据成为可能通过
MediaStream
or
HTMLMediaElement
对象为分析、处理或保存到磁盘。它还出人意料的易于使用。
The MediaStream Recording API is comprised of a single major interface,
MediaRecorder
, which does all the work of taking the data from a
MediaStream
and delivering it to you for processing. The data is delivered by a series of
dataavailable
events, already in the format you specify when creating the
MediaRecorder
. You can then process the data further or write it to file as desired.
录制流的过程很简单：
MediaStream
or
HTMLMediaElement
(in the form of an
<audio>
or
<video>
element) to serve as the source of the media data.
MediaRecorder
object, specifying the source stream and any desired options (such as the container's MIME type or the desired bit rates of its tracks).
MediaRecorder.ondataavailable
to an event handler for the
dataavailable
event; this will be called whenever data is available for you.
MediaRecorder.start()
to begin recording.
dataavailable
event handler gets called every time there's data ready for you to do with as you will; the event has a
data
attribute whose value is a
Blob
that contains the media data. You can force a
dataavailable
event to occur, thereby delivering the latest sound to you so you can filter it, save it, or whatever.
MediaRecorder.stop()
.
注意：
Individual
Blob
s containing slices of the recorded media will not necessarily be individually playable. The media needs to be reassembled before playback.
If anything goes wrong during recording, an
error
event is sent to the
MediaRecorder
. You can listen for
error
events by setting up a
onerror
event handler.
Example here, we use an HTML Canvas as source of the
MediaStream
, and stop recording after 9 seconds.
var canvas = document.querySelector("canvas");
// Optional frames per second argument.
var stream = canvas.captureStream(25);
var recordedChunks = [];
console.log(stream);
var options = { mimeType: "video/webm; codecs=vp9" };
mediaRecorder = new MediaRecorder(stream, options);
mediaRecorder.ondataavailable = handleDataAvailable;
mediaRecorder.start();
function handleDataAvailable(event) {
console.log("data-available");
if (event.data.size > 0) {
recordedChunks.push(event.data);
console.log(recordedChunks);
download();
} else {
// ...
}
}
function download() {
var blob = new Blob(recordedChunks, {
type: "video/webm"
});
var url = URL.createObjectURL(blob);
var a = document.createElement("a");
document.body.appendChild(a);
a.style = "display: none";
a.href = url;
a.download = "test.webm";
a.click();
window.URL.revokeObjectURL(url);
}
// demo: to download after 9sec
setTimeout(event => {
console.log("stopping");
mediaRecorder.stop();
}, 9000);
You can also use the properties of the
MediaRecorder
object to determine the state of the recording process, and its
pause()
and
resume()
methods to pause and resume recording of the source media.
If you need or want to check to see if a specific MIME type is supported, that's possible as well. Just call
MediaRecorder.isTypeSupported()
.
If your goal is to record camera and/or microphone input, you may wish to examine the available input devices before beginning the process of constructing the
MediaRecorder
. To do so, you'll need to call
navigator.mediaDevices.enumerateDevices()
to get a list of the available media devices. You can then examine that list and identify the potential input sources, and even filter the list based on desired criteria.
In this code snippet,
enumerateDevices()
is used to examine the available input devices, locate those which are audio input devices, and create
<option>
elements that are then added to a
<select>
element representing an input source picker.
navigator.mediaDevices.enumerateDevices()
.then(function(devices) {
devices.forEach(function(device) {
let menu = document.getElementById("inputdevices");
if (device.kind == "audioinput") {
let item = document.createElement("option");
item.innerHTML = device.label;
item.value = device.deviceId;
menu.appendChild(item);
}
});
});
Code similar to this can be used to let the user restrict the set of devices they wish to use.
To learn more about using the MediaStream Recording API, see
Using the MediaStream Recording API
, which shows how to use the API to record audio clips. A second article,
Recording a media element
, describes how to receive a stream from an
<audio>
or
<video>
element and use the captured stream (in this case, recording it and saving it to a local disk).
BlobEvent
Blob
form using a
BlobEvent
类型
dataavailable
.
MediaRecorder
The primary interface that implements the MediaStream Recording API.
MediaRecorderErrorEvent
error
特性为
DOMException
that specifies that error occurred.
| 规范 | 状态 | 注释 |
|---|---|---|
| MediaStream 录制 | 工作草案 | 初始定义 |
MediaRecorder
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
MediaRecorder
|
Chrome 47 | Edge 79 |
Firefox
25
|
IE No | Opera 36 | Safari No | WebView Android 47 | Chrome Android 47 |
Firefox Android
25
|
Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
MediaRecorder()
构造函数
|
Chrome 47 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 47 | Chrome Android 47 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
audioBitsPerSecond
|
Chrome 49 | Edge 79 | Firefox 71 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android ? | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
error
event
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
ignoreMutedMedia
弃用
非标
|
Chrome 49 — 57 | Edge No | Firefox ? | IE No | Opera 36 — 44 | Safari No | WebView Android 49 — 57 | Chrome Android 49 — 57 | Firefox Android ? | Opera Android 36 — 44 | Safari iOS No | Samsung Internet Android 5.0 — 7.0 |
isTypeSupported
|
Chrome 47 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 47 | Chrome Android 47 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
mimeType
|
Chrome
49
|
Edge 79 |
Firefox
25
|
IE No | Opera 36 | Safari No |
WebView Android
49
|
Chrome Android
49
|
Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
ondataavailable
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onerror
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onpause
|
Chrome 49 | Edge 79 | Firefox 65 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 65 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onresume
|
Chrome 49 | Edge 79 | Firefox 65 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 65 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onstart
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onstop
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
onwarning
弃用
|
Chrome 49 | Edge 79 | Firefox 25 — 71 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
pause
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
requestData
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
resume
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
start
|
Chrome 47 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 47 | Chrome Android 47 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
state
|
Chrome
49
|
Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No |
WebView Android
49
|
Chrome Android
49
|
Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
stop
|
Chrome 49 | Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
stream
|
Chrome
49
|
Edge 79 | Firefox 25 | IE No | Opera 36 | Safari No | WebView Android 49 |
Chrome Android
49
|
Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
videoBitsPerSecond
|
Chrome 49 | Edge 79 | Firefox 71 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android ? | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
warning
event
弃用
|
Chrome 49 | Edge 79 | Firefox 25 — 71 | IE No | Opera 36 | Safari No | WebView Android 49 | Chrome Android 49 | Firefox Android 25 | Opera Android 36 | Safari iOS No | Samsung Internet Android 5.0 |
完整支持
不支持
兼容性未知
实验。期望将来行为有所改变。
非标。预期跨浏览器支持较差。
弃用。不要用于新网站。
见实现注意事项。
navigator.mediaDevices.getUserMedia()