OnnxRuntime Plugin

Overview

Flutter plugin for OnnxRuntime via dart:ffi provides an easy, flexible, and fast Dart API to integrate Onnx models in flutter apps across mobile and desktop platforms.

*: Consistent with Flutter

Key Features

• Multi-platform Support for Android, iOS, Linux, macOS, Windows, and Web(Coming soon).
• Flexibility to use any Onnx Model.
• Acceleration using multi-threading.
• Similar structure as OnnxRuntime Java and C# API.
• Inference speed is not slower than native Android/iOS Apps built using the Java/Objective-C API.
• Run inference in different isolates to prevent jank in UI thread.

Getting Started

In your flutter project add the dependency:

dependencies:
  ...
  onnxruntime: x.y.z

Usage example

Import

import 'package:onnxruntime/onnxruntime.dart';

Initializing environment

OrtEnv.instance.init();

Creating the Session

final sessionOptions = OrtSessionOptions();
const assetFileName = 'assets/models/test.onnx';
final rawAssetFile = await rootBundle.load(assetFileName);
final bytes = rawAssetFile.buffer.asUint8List();
final session = OrtSession.fromBuffer(bytes, sessionOptions!);

Performing inference

final shape = [1, 2, 3];
final inputOrt = OrtValueTensor.createTensorWithDataList(data, shape);
final inputs = {'input': inputOrt};
final runOptions = OrtRunOptions();
final outputs = await _session?.runAsync(runOptions, inputs);
inputOrt.release();
runOptions.release();
outputs?.forEach((element) {
  element?.release();
});

Releasing environment

OrtEnv.instance.release();