MediaRecorder: Record from Multiple Microphones

问题

I am currently using the MediaRecorder API to record audio inside an application.

Is there a way to record from multiple input devices, say, two microphones?

I can get a list of devices using mediaDevices.enumerateDevices(), as demonstrated here.

Ideally, if possible, I would like to select two or more devices to be recorded.

Is this possible?

回答1:

this function will merge your tracks into one:

function mix(audioContext, streams) {
  const dest = audioContext.createMediaStreamDestination();
  streams.forEach(stream => {
    const source = audioContext.createMediaStreamSource(stream);
    source.connect(dest);
  });
  return dest.stream.getTracks()[0];
}

回答2:

The solution to this was to request multiple getUserMedia and mix the streams with AudioContext.

Here's how to do that.

const VIDEO_ID = 'video_id';
const MIC_1_ID = 'mic_1_id';
const MIC_2_ID = 'mic_2_id';

// Request permission
navigator.mediaDevices.getUserMedia({video: true, audio: true}).then(() => {

    // Loop over all available video and audio devices (input and output)
    navigator.mediaDevices.enumerateDevices().then(devices => {

        // Request exact devices
        const requests = [
            navigator.mediaDevices.getUserMedia({video: {deviceId: {exact: VIDEO_ID}}}),
            navigator.mediaDevices.getUserMedia({video: false, audio: {deviceId: {exact: MIC_1_ID}}}),
            navigator.mediaDevices.getUserMedia({video: false, audio: {deviceId: {exact: MIC_2_ID}}})
        ];

        // Wait for all device requests to resolve.
        Promise.all(requests).then(streams => {
            const ctx = new AudioContext();
            const dest = ctx.createMediaStreamDestination();

            // Connect streams to the destination audio stream.
            streams.map(stream => {
                ctx.createMediaStreamSource(stream).connect(dest);
            });

            const videoTrack = streams[0].getTracks()[0];
            const mixedTracks = dest.stream.getTracks()[0];

            // Combine video and audio tracks into single stream.
            const stream = new MediaStream([videoTrack, mixedTracks]);

            // Start recorder
            const recorder = new MediaRecorder(this.stream, this.settings.recorder);

            // ...
        });

    });
});

来源：https://stackoverflow.com/questions/47059324/mediarecorder-record-from-multiple-microphones

标签

javascript

audio