{ 
  "moz:firefoxOptions": {
    "prefs": {
      "media.navigator.streams.fake": true,
      "media.navigator.permission.disabled": true
    },
    "args": []
  },
  "goog:chromeOptions": {
    "args": [
      "--use-fake-device-for-media-stream",
      "--use-fake-ui-for-media-stream"
    ]
  }
}