{
  "duration": 3000000,
  "tracks": [
    {
      "segments": [
        {
          "target_timerange": {
            "start": 0,
            "duration": 2000000
          }
        },
        {
          "target_timerange": {
            "start": 2000000,
            "duration": 1000000
          }
        }
      ]
    }
  ],
  "materials": {
    "videos": [
      {
        "id": "synthetic-media"
      }
    ]
  }
}