Android Chrome Switch from Front to Rear camera using JavaScript

Question

I can't figure this out properly, or if it's even possible to switch cameras.

I've tried stopping the video track before calling getUserMedia a second time, hoping that stopping the video track would turn the front camera off so the rear camera can turn on, but it just doesn't work.

var oldStream; // the old stream from getUserMedia

Function SwitchCamera() {

    oldStream.getVideoTracks()[0].stop();

    navigator.mediaDevices.getUserMedia({audio: true, video: {deviceId: 'rear camera device ID'}).then(function(newStream){

        // this never runs

    }).catch(function(err){
        console.log(err); // Cannot connect camera
    });

}

Is there something else that I need to do to switch cameras on mobile? Is this even possible?

Answer 1

On mobile, it appears we just need to give the camera enough time to shut down. Wrapping getUserMedia in a setTimeout with a delay of about 1 second (1,000 ms) is sufficient for my testing, though I'm also going to attempt to swap the camera 3 times consecutively before throwing an error. I'm not sure how, or even if it's possible, to check if the actual device is stopped or turned off, but I suspect that's impossible due to browser security.

In a perfect world MediaStreamTrack.stop() would return a promise that gives us information about whether the device associated with the track is actually stopped/off or if it is still running due to it being used in other tracks.