MediaStreamTrackAudioSourceNode

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构造函数
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MediaStreamTrackAudioSourceNode interface is a type of AudioNode which represents a source of audio data taken from a specific MediaStreamTrack obtained through the WebRTC or 媒体捕获和流 API。 The audio itself might be input from a microphone or other audio sampling device, or might be received through a RTCPeerConnection , among other posible options.

A MediaStreamTrackAudioSourceNode has no inputs and exactly one output, and is created using the AudioContext.createMediaStreamTrackSource() method. This interface is similar to MediaStreamAudioSourceNode , except it lets you specifically state the track to use, rather than assuming the first audio track on a stream.

输入数	`0`
输出数	`1`
通道计数	defined by the first audio `MediaStreamTrack` passed to the `AudioContext.createMediaStreamTrackSource()` method that created it.

构造函数

new MediaStreamTrackAudioSourceNode(): 创建新的 MediaStreamTrackAudioSourceNode object instance with the specified options.

特性

MediaStreamTrackAudioSourceNode interface has no properties of its own; however, it inherits the properties of its parent, AudioNode .

方法

继承方法来自其父级 AudioNode .

范例

In this example, we grab a media (audio + video) stream from navigator.getUserMedia , feed the media into a <video> element to play then mute the audio, but then also feed the audio into a MediaStreamAudioSourceNode . Next, we feed this source audio into a low pass BiquadFilterNode (which effectively serves as a bass booster), then a AudioDestinationNode .

The range slider below the <video> element controls the amount of gain given to the lowpass filter — increase the value of the slider to make the audio sound more bass heavy!

注意 : You can see this example running live ，或 view the source .

var pre = document.querySelector('pre');
var video = document.querySelector('video');
var myScript = document.querySelector('script');
var range = document.querySelector('input');
// getUserMedia block - grab stream
// put it into a MediaStreamAudioSourceNode
// also output the visuals into a video element
if (navigator.mediaDevices) {
    console.log('getUserMedia supported.');
    navigator.mediaDevices.getUserMedia ({audio: true, video: true})
    .then(function(stream) {
        video.srcObject = stream;
        video.onloadedmetadata = function(e) {
            video.play();
            video.muted = true;
        };
        // Create a MediaStreamAudioSourceNode
        // Feed the HTMLMediaElement into it
        var audioCtx = new AudioContext();
        var source = audioCtx.createMediaStreamSource(stream);
        // Create a biquadfilter
        var biquadFilter = audioCtx.createBiquadFilter();
        biquadFilter.type = "lowshelf";
        biquadFilter.frequency.value = 1000;
        biquadFilter.gain.value = range.value;
        // connect the AudioBufferSourceNode to the gainNode
        // and the gainNode to the destination, so we can play the
        // music and adjust the volume using the mouse cursor
        source.connect(biquadFilter);
        biquadFilter.connect(audioCtx.destination);
        // Get new mouse pointer coordinates when mouse is moved
        // then set new gain value
        range.oninput = function() {
            biquadFilter.gain.value = range.value;
        }
    })
    .catch(function(err) {
        console.log('The following gUM error occured: ' + err);
    });
} else {
   console.log('getUserMedia not supported on your browser!');
}
// dump script to pre element
pre.innerHTML = myScript.innerHTML;

注意 : As a consequence of calling createMediaStreamSource() , audio playback from the media stream will be re-routed into the processing graph of the AudioContext . So playing/pausing the stream can still be done through the media element API and the player controls.

规范

规范	状态	注释
Web 音频 API The definition of 'MediaStreamTrackAudioSourceNode' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`MediaStreamTrackAudioSourceNode`	Chrome 不支持 No	Edge 不支持 No	Firefox 68	IE 不支持 No	Opera 不支持 No	Safari 不支持 No	WebView Android 不支持 No	Chrome Android 不支持 No	Firefox Android 68	Opera Android 不支持 No	Safari iOS 不支持 No	Samsung Internet Android 不支持 No
`MediaStreamTrackAudioSourceNode()` 构造函数	Chrome 不支持 No	Edge 不支持 No	Firefox 68 注意事项 68 注意事项 Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	IE 不支持 No	Opera 不支持 No	Safari 不支持 No	WebView Android 不支持 No	Chrome Android 不支持 No	Firefox Android 68 注意事项 68 注意事项 Firefox 68 implements the updated standard's definition of the "first" audio track; now the first track is the one whose ID comes first lexicographically.	Opera Android 不支持 No	Safari iOS 不支持 No	Samsung Internet Android 不支持 No
`mediaStreamTrack`	Chrome 不支持 No	Edge 不支持 No	Firefox 68	IE 不支持 No	Opera 不支持 No	Safari 不支持 No	WebView Android 不支持 No	Chrome Android 不支持 No	Firefox Android 68	Opera Android 不支持 No	Safari iOS 不支持 No	Samsung Internet Android 不支持 No

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构造函数

特性

方法

范例

规范

浏览器兼容性

图例

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