Rhino Speech-to-Intent
Flutter Quick Start

Platforms

• Flutter (2.8.1+)
• Android (5.0+, API 21+)
• iOS (13.0+)

Requirements

• Flutter SDK
• Android SDK (21+)
• JDK (11+)
• Xcode (13+)

Picovoice Account & AccessKey

Signup or Login to Picovoice Console to get your AccessKey. Make sure to keep your AccessKey secret.

Quick Start

Setup

1. Install Flutter SDK.

2. Run flutter doctor to determine any missing requirements.

3. Add the Rhino Speech-to-Intent plugin to your app project by referencing it in pubspec.yaml:

dependencies:
  rhino_flutter: ^<version>

4. Enable the proper permission for recording with the hardware's microphone on both iOS and Android:

<key>NSMicrophoneUsageDescription</key>
<string>[Permission explanation]</string>

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.INTERNET" />

Usage

1. Add the context file (either a pre-built context file (.rhn) from the Rhino Speech-to-Intent GitHub Repository or a custom context created with the Picovoice Console) to the assets folder in the project directory.

2. Add the path to the pubspec.yaml:

flutter:
  assets:
    - assets/${CONTEXT_FILE}

3. Create an instance of RhinoManager using the constructor RhinoManager.create that infers custom commands:

import 'package:rhino_flutter/rhino.dart';
import 'package:rhino_flutter/rhino_manager.dart';
import 'package:rhino_flutter/rhino_error.dart';

RhinoManager? _rhinoManager;

try {
  _rhinoManager = await RhinoManager.create(
    "{ACCESS_KEY}"
    "assets/{CONTEXT_FILE}",
    _inferenceCallback);
} on RhinoException catch (err) {
  // handle Rhino init error
}

The _inferenceCallback parameter is a function that is invoked when Rhino Speech-to-Intent made an intent inference.

void _inferenceCallback(RhinoInference inference) {
  if (inference.isUnderstood!) {
    String intent = inference.intent!;
    Map<String, String> slots = inference.slots!;
    // take action based on inferred intent and slot values
  } else {
    // handle unsupported commands
  } 
}

Start audio capture and intent inference:

try{
  await _rhinoManager.process();
} on RhinoException catch (err) { }

Once an inference has been made, the _inferenceCallback will be invoked and audio capture will stop automatically. Release resources explicitly when done with Rhino Speech-to-Intent:

await _rhinoManager.delete();

Custom Contexts

1. Create custom contexts with the Picovoice Console. Download the custom context file (.rhn).

2. Add the file to the assets folder in the project directory.

3. Add it to the pubspec.yaml:

flutter:
  assets:
    - assets/${CUSTOM_CONTEXT_FILE}

3. Create an instance of RhinoManager using the constructor RhinoManager.create with the custom context.

Alternatively, if the context file is deployed to the device with a different method, the absolute path to the file on device can be used.

Non-English Languages

Use the corresponding model file (.pv) to detect non-English wake words. The model files for all supported languages are available on the Rhino Speech-to-Intent GitHub repository.

1. Add the file to the assets folder in the project directory.
2. Add it to the pubspec.yaml:

flutter:
  assets:
    - assets/${CUSTOM_CONTEXT_FILE}
    - assets/${MODEL_FILE}

3. Pass in the model file using the modelPath parameter to change the language:

try{
  _rhinoManager = await RhinoManager.create(
    "{ACCESS_KEY}"
    "assets/{CUSTOM_CONTEXT_FILE}",
    _inferenceCallback,
    modelPath: "assets/{MODEL_FILE}");
} on RhinoException catch (err) {
  // handle Rhino init error
}

Alternatively, if the model file is deployed to the device with a different method, the absolute path to the file on device can be used.

Demo

For the Rhino Speech-to-Intent Flutter SDK, we offer demo applications that demonstrate how to use the Speech-to-Intent engine on real-time audio streams (i.e. microphone input).

Setup

Clone the Rhino Speech-to-Intent GitHub Repository:

git clone --recurse-submodules https://github.com/Picovoice/rhino.git

Usage

1. Replace {YOUR_ACCESS_KEY_HERE} with a valid AccessKey in the demo/flutter/lib/main.dart file:

2. Run the prepare_demo script with a language code to set up the demo in the language of your choice (e.g. de -> German, ko -> Korean). To see a list of available languages, run prepare_demo without a language code.

cd rhino/demo/flutter
dart scripts/prepare_demo.dart ${LANGUAGE}

3. Build and deploy the demo to your device:

flutter run

For more information on our Rhino Speech-to-Intent demos for Flutter, head over to our GitHub repository.

Resources