{
  "$ref": "core/room_event.json",
  "type": "m.room.message",
  "content": {
    "body": "Bee Gees - Stayin' Alive",
    "url": "mxc://example.org/ffed755USFFxlgbQYZGtryd",
    "info": {
      "duration": 2140786,
      "size": 1563685,
      "mimetype": "audio/mpeg"
    },
    "msgtype": "m.audio"
  }
}