Take audio element as source, take capture stream from this element and create a media recorder with this stream. After this media stream finish playback, media recorder should send out onstop state "automatically". Meanwhile, call requestData/stop/ start at this moment should get DOM InvalidState error. The same for MediaStreamDestination which generate from an AudioContext

Is captureStream() or captureStreamUntilEnded() called? https://dvcs.w3.org/hg/audio/raw-file/tip/streams/StreamProcessing.html#media-elements 3.1 "The captureStream() method returns a new MediaStream that plays the same audio and video as stream. captureStream() sets the audioCaptured attribute to true." "The captureStreamUntilEnded() method returns a new MediaStream that plays the same audio and video as stream, until the element next reaches the "ended playback" state, at which point this stream will enter the finished state. captureStreamUntilEnded() sets the audioCaptured attribute to true." It looks like only the stream returned by captureStreamUntilEnded() could enter the finished state, if I read it correctly.

Free it if someone want it.

I believe now the onstop event will dispatch to JS when stream ended.