Buses Configuration

This configuration file allows you to register the list of buses Amplitude will use in the engine. For each bus, you can configure settings for auto-ducking between them.

When configuring buses, you are allowed to create as many buses as you want, but there should be at least one master bus. The master bus is a special bus that controls all the other buses. It should have a id attribute set to 1 and a name attribute set to master.

buses#

array required

The buses property is the only root property of this file. It should store an array of bus objects describing the settings for each bus Amplitude will use at runtime. Each object of this array should have the following properties:

id#

uint64 required default: 0

The unique identifier of the bus. This value should be unique per bus and should have a value different from 0. There is a special rule for the master bus which should have this value set to 1.

name#

string required

The unique name of the bus. This value is required and should be unique per bus. There is a special rule for the master bus which should have this value set to master.

gain#

float default: 1.0

The linear gain is applied to all the sound objects playing on the bus. If set to 0.0, all the sound objects of this bus will be muted.

The final gain of a bus is calculated by multiplying this value with the parent bus’ gain, a user-specified gain provided at runtime, and this bus ducked gain.

child_buses#

array optional

The child_buses property stores a list of integer values, each value representing the id of a bus that should be considered as a child of this one. Child buses are affected by the parent bus’ final gain. So if the parent bus is muted (gain = 0.0), then all the children of this bus will be muted too.

For the master bus to work properly, you may want to feed his child_buses property with all the root buses (buses with no parent) of your configuration. That way, the master bus will correctly control the gain of all the other buses.

duck_buses#

array optional

duck_buses is an array of objects allowing you to set up a ducking behavior between two or more buses that play sound objects simultaneously. Each object of this array should have the following properties:

• id: This is the ID of the bus to control between the list of declared buses.
• target_gain: This specifies the target gain the controlled bus should have after the ducking is done.
• fade_in: This is the fader setting used when the controlled bus is being ducked to the target gain.
• fade_out: This is the fader setting used when the controlled bus is being restored to its original gain.

fader#

string required

This property stores the name of the fader algorithm that will be used when the gain of this bus is manually updated at runtime.

Example#

An example of a bus configuration file may look like:

{
  "buses": [
    {
      "id": 1,
      "name": "master",
      "gain": 1.0,
      "child_buses": [
        2,
        7678456242523
      ],
      "fader": "Linear"
    },
    {
      "id": 2,
      "name": "voices",
      "gain": 1,
      "duck_buses": [
        {
          "id": 7678456242523,
          "target_gain": 0.25,
          "fade_in": {
            "duration": 3,
            "fader": "SCurveSmooth"
          },
          "fade_out": {
            "duration": 3,
            "fader": "Linear"
          }
        }
      ],
      "fader": "Linear"
    },
    {
      "id": 7678456242523,
      "name": "environment",
      "gain": 0.75,
      "fader": "Linear"
    }
  ]
}