parameters.json Format

Define plugin parameters in a JSON file for cross-language code generation.

File Structure

{
  "parameters": [
    {
      "id": "GAIN",
      "name": "Gain",
      "type": "float",
      "min": -60.0,
      "max": 30.0,
      "defaultValue": 0.0,
      "unit": "dB"
    },
    {
      "id": "PAN",
      "name": "Pan",
      "type": "float",
      "min": -100.0,
      "max": 100.0,
      "defaultValue": 0.0
    },
    {
      "id": "MONO",
      "name": "Mono",
      "type": "boolean",
      "defaultValue": false
    },
    {
      "id": "MODE",
      "name": "Routing Mode",
      "type": "choice",
      "choices": ["Stereo", "Left", "Right", "Swap"],
      "defaultValueIndex": 0
    }
  ]
}

Field Reference

Required Fields

Field	Type	Description
`id`	string	Parameter identifier (uppercase, used in code generation)
`name`	string	Display name for UI
`type`	string	`"boolean"`, `"float"`, or `"choice"`

Boolean Parameters

Field	Type	Description
`defaultValue`	boolean	Default state (`true` or `false`)

Float Parameters

Field	Type	Description
`min`	number	Minimum value
`max`	number	Maximum value
`defaultValue`	number	Default value
`unit`	string	Optional unit label (e.g., "dB", "Hz", "%")
`midpoint`	number	Optional midpoint for skewed ranges
`interval`	number	Optional step interval
`fractionDigits`	integer	Optional decimal places to display

Choice Parameters

Field	Type	Description
`choices`	string[]	Array of option labels
`defaultValueIndex`	integer	Index of default choice (0-based)

Complete Example

{
  "parameters": [
    {
      "id": "INVERT_LEFT",
      "name": "Invert Left",
      "type": "boolean",
      "defaultValue": false
    },
    {
      "id": "INVERT_RIGHT",
      "name": "Invert Right",
      "type": "boolean",
      "defaultValue": false
    },
    {
      "id": "CHANNEL_MODE",
      "name": "Channel Mode",
      "type": "choice",
      "choices": ["Stereo", "Left", "Right", "Swap"],
      "defaultValueIndex": 0
    },
    {
      "id": "MONO",
      "name": "Sum to Mono",
      "type": "boolean",
      "defaultValue": false
    },
    {
      "id": "GAIN",
      "name": "Gain",
      "type": "float",
      "min": -60.0,
      "max": 30.0,
      "defaultValue": 0.0,
      "unit": "dB",
      "fractionDigits": 1
    },
    {
      "id": "PAN",
      "name": "Pan",
      "type": "float",
      "min": -100.0,
      "max": 100.0,
      "defaultValue": 0.0,
      "interval": 1.0
    },
    {
      "id": "DC_OFFSET",
      "name": "DC Offset Removal",
      "type": "boolean",
      "defaultValue": false
    }
  ]
}

Parsing in Rust

#![allow(unused)]
fn main() {
use bbx_plugin::ParamsFile;

fn load_parameters() -> ParamsFile {
    let json = include_str!("../parameters.json");
    ParamsFile::from_json(json).expect("Failed to parse parameters.json")
}
}

Generated Output

From the above JSON, code generation produces:

Rust:

#![allow(unused)]
fn main() {
pub const PARAM_INVERT_LEFT: usize = 0;
pub const PARAM_INVERT_RIGHT: usize = 1;
pub const PARAM_CHANNEL_MODE: usize = 2;
pub const PARAM_MONO: usize = 3;
pub const PARAM_GAIN: usize = 4;
pub const PARAM_PAN: usize = 5;
pub const PARAM_DC_OFFSET: usize = 6;
pub const PARAM_COUNT: usize = 7;
}

C Header:

#define PARAM_INVERT_LEFT 0
#define PARAM_INVERT_RIGHT 1
#define PARAM_CHANNEL_MODE 2
#define PARAM_MONO 3
#define PARAM_GAIN 4
#define PARAM_PAN 5
#define PARAM_DC_OFFSET 6
#define PARAM_COUNT 7

bbx_audio Documentation