Flutter音频处理插件vad的使用

Flutter音频处理插件vad的使用

示例代码

// main.dart
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:vad/vad.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'VAD Example',
      theme: ThemeData.dark().copyWith(
        primaryColor: Colors.blue,
        scaffoldBackgroundColor: const Color(0xFF121212),
        cardColor: const Color(0xFF1E1E1E),
        sliderTheme: SliderThemeData(
          activeTrackColor: Colors.blue[400],
          inactiveTrackColor: Colors.grey[800],
          thumbColor: Colors.blue[300],
          overlayColor: Colors.blue.withAlpha(32),
        ),
        elevatedButtonTheme: ElevatedButtonThemeData(
          style: ElevatedButton.styleFrom(
            backgroundColor: Colors.blue[700],
            foregroundColor: Colors.white,
          ),
        ),
        textButtonTheme: TextButtonThemeData(
          style: TextButton.styleFrom(
            foregroundColor: Colors.blue[300],
          ),
        ),
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final _vadHandler = VadHandler.create(isDebug: true);
  bool isListening = false;
  int frameSamples = 1536; // 1帧 = 1536样本 = 96ms
  int minSpeechFrames = 3;

  @override
  void initState() {
    super.initState();
    _setupVadHandler();
  }

  void _setupVadHandler() {
    _vadHandler.onSpeechStart.listen((_) {
      debugPrint('Speech detected.');
    });

    _vadHandler.onSpeechEnd.listen((List<double> samples) {
      setState(() {
        print('Speech ended, first 10 samples: ${samples.take(10).toList()}');
      });
    });

    _vadHandler.onError.listen((String message) {
      debugPrint('Error: $message');
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("VAD Example"),
        backgroundColor: Colors.black,
        elevation: 0,
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.symmetric(vertical: 8.0),
              itemCount: 10,
              itemBuilder: (context, index) {
                return ListTile(
                  title: Text('Recording ${index + 1}'),
                  subtitle: Text('Speech start'),
                  onTap: () {
                    if (_vadHandler.isListening) {
                      _vadHandler.stopListening();
                    } else {
                      _vadHandler.startListening();
                    }
                    setState(() {
                      isListening = !isListening;
                    });
                  },
                );
              },
            ),
          ),
          Container(
            padding: const EdgeInsets.all(16.0),
            decoration: BoxDecoration(
              color: Colors.black,
              boxShadow: [
                BoxShadow(
                  color: Colors.black.withOpacity(0.3),
                  spreadRadius: 1,
                  blurRadius: 10,
                  offset: const Offset(0, -1),
                ),
              ],
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                ElevatedButton.icon(
                  onPressed: () async {
                    final status = await Permission.microphone.request();
                    debugPrint("Microphone permission status: $status");
                  },
                  icon: Icon(isListening ? Icons.stop : Icons.mic),
                  label:
                      Text(isListening ? "Stop Listening" : "Start Listening"),
                  style: ElevatedButton.styleFrom(
                    minimumSize: const Size(double.infinity, 48),
                  ),
                ),
                const SizedBox(height: 8),
                TextButton.icon(
                  onPressed: () async {
                    final status = await Permission.microphone.request();
                    debugPrint("Microphone permission status: $status");
                  },
                  icon: const Icon(Icons.settings_voice),
                  label: const Text("Request Microphone Permission"),
                  style: TextButton.styleFrom(
                    minimumSize: const Size(double.infinity, 48),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

示例代码解释

1. 初始化VAD Handler：

   final _vadHandler = VadHandler.create(isDebug: true);
   

   创建一个VAD处理器实例，并启用调试模式。

2. 监听事件：

   _vadHandler.onSpeechStart.listen((_) {
     debugPrint('Speech detected.');
   });
   
   _vadHandler.onSpeechEnd.listen((List<double> samples) {
     setState(() {
       print('Speech ended, first 10 samples: ${samples.take(10).toList()}');
     });
   });
   
   _vadHandler.onError.listen((String message) {
     debugPrint('Error: $message');
   });
   

   监听语音开始、结束和错误事件。

3. 控制监听状态：

   if (_vadHandler.isListening) {
     _vadHandler.stopListening();
   } else {
     _vadHandler.startListening();
   }
   

   根据当前是否在监听，启动或停止监听。

4. 请求麦克风权限：

   final status = await Permission.microphone.request();
   

   请求麦克风权限。

5. UI布局：

   Expanded(child: ListView.builder(...))