是否可以更改 MediaRecorder 的流? [英] Is it possible to change MediaRecorder's stream?

问题描述

getUserMedia(constrains).then(stream => {
    var recorder = new MediaRecorder(stream)
})

recorder.start()
recorder.pause()
// get new stream getUserMedia(constrains_new)
// how to update recorder stream here?
recorder.resume()

有可能吗?我尝试创建 MediaStream 并使用 addTrack 和 removeTrack 方法来更改流轨道但没有成功(当我尝试使用更新的流恢复它时，记录器停止)

Is it possible? I've try to create MediaStream and use addTrack and removeTrack methods to change stream tracks but no success (recorder stops when I try to resume it with updated stream)

有什么想法吗?

推荐答案

简短的回答是否定的，这是不可能的.MediaStream 录制规范 明确描述了这种行为:https://w3c.github.io/mediacapture-record/#dom-mediarecorder-start.该算法的要点 15.3 说如果在任何时候，一个轨道被添加到流的轨道集中或从流的轨道集中删除，UA 必须立即停止收集数据......".

The short answer is no, it's not possible. The MediaStream recording spec explicitly describes this behavior: https://w3c.github.io/mediacapture-record/#dom-mediarecorder-start. It's bullet point 15.3 of that algorithm which says "If at any point, a track is added to or removed from stream’s track set, the UA MUST immediately stop gathering data ...".

但如果您只想录制音频，您可以使用 AudioContext 来代理您的流.创建 MediaStreamAudioDestinationNode 并使用它提供的流进行录制.然后，您可以将带有 MediaStreamAudioSourceNodes 和/或 MediaStreamTrackAudioSourceNodes 的流送入音频图中，并以您想要的任何方式混合它们.

But in case you only want to record audio you can probably use an AudioContext to proxy your streams. Create a MediaStreamAudioDestinationNode and use the stream that it provides for recording. Then you can feed your streams with MediaStreamAudioSourceNodes and/or MediaStreamTrackAudioSourceNodes into the audio graph and mix them in any way you desire.

最后但并非最不重要的是，目前计划将您正在寻找的功能添加到规范中.也许你只需要等一会儿.或者可能会更长一些，具体取决于您使用的浏览器.:-)

Last but not least there are currently plans to add the functionality you are looking for to the spec. Maybe you just have to wait a bit. Or maybe a bit longer depending on the browser you are using. :-)

https://github.com/w3c/mediacapture-record/issues/167

https://github.com/w3c/mediacapture-record/pull/186

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