将两个音轨合并为一个音轨

Question

我在将两个音轨合并为一个音轨以将整个合并的音频添加到视频音轨时遇到问题。

this.promises = [navigator.mediaDevices.getUserMedia({ audio: true, video: true })];
if (navigator['getDisplayMedia']) {
this.promises.push(navigator['getDisplayMedia'](this.streamConstraints));
}
else if (navigator.mediaDevices['getDisplayMedia']) {
this.promises.push(navigator.mediaDevices['getDisplayMedia'](this.streamConstraints));
}
else {
this.promises.push(navigator.mediaDevices.getUserMedia({ video: { mediaSource: 'screen' } as any }));
}
Promise.all(this.promises)
.then((streams) => {
// so here is the microphone audio and webcam video
const avTracks = streams[0].getTracks();
// here is the screen video and audio
const screenRecordTracks = streams[1].getTracks();
const firstAudioTrack = new MediaStream(avTracks).getAudioTracks();
const secondAudioTrack= new MediaStream(screenRecordTracks ).getAudioTracks();
// so here I want to merge these two audio tracks, and them to add this final track to the first video track like so..
const wholeRecord = new MediaStream(avTracks).getVideoTracks(); + the merged audio track

我怎样才能把它们合并成一首歌，有人能帮我吗？

Answer 1

我可以通过使用WebAudio API来实现这一点。我从两个流中提取了音轨，并使用音频上下文将它们连接到一个流中。

var OutgoingAudioMediaStream = new MediaStream();
OutgoingAudioMediaStream.addTrack(OutgoingStream.getAudioTracks()[0]);
var IncomingAudioMediaStream = new MediaStream();
IncomingAudioMediaStream.addTrack(IncomingStream.getAudioTracks()[0]);
const audioContext = new AudioContext();
audioIn_01 = audioContext.createMediaStreamSource(OutgoingAudioMediaStream);
audioIn_02 = audioContext.createMediaStreamSource(IncomingAudioMediaStream);
dest = audioContext.createMediaStreamDestination();
audioIn_01.connect(dest);
audioIn_02.connect(dest);
var FinalStream = dest.stream;

这非常有效。