var getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;

var URL = window.URL || window.webkitURL;

var currentStream;

​

​

$('#video').on('loadeddata', function() {

  var video = this;

  this.play();

  setTimeout(function() {

    console.log(video.videoWidth, video.videoHeight);

  }, 1000);

});

​

​

function close() {

  if (currentStream) {

    currentStream.stop();

  }

}

​

​

function run(minWidth) {

  var constraints = {

    video: {

      optional: [

        {minWidth: minWidth}

      ]

    }

  };

  getUserMedia.call(navigator, constraints, function(stream) {

    currentStream = stream;

    $('#video').prop('src', URL.createObjectURL(stream));

    $('#video')[0].play();

  }, function() {

    alert('failed');

  });

}

​

$('#2048').on('click', function() {

  close();

  run(2048);

});

$('#1600').on('click', function() {

  close();

  run(1600);

});