mic_stream_recorder #

A Flutter plugin for real-time microphone audio stream recording on iOS and Android platforms with amplitude monitoring and configurable settings.

Features #

• 🎤 Real-time microphone recording with M4A/AAC format
• 📊 Live amplitude monitoring for audio visualization
• 📱 Cross-platform support (iOS & Android)
• ⚙️ Configurable settings (sample rate, channels, quality, buffer size)
• 🎵 Playback controls (play, pause, stop)
• 🛡️ Automatic permission handling for microphone access
• ⚡ Low latency real-time audio processing
• 🎯 Simple API with comprehensive error handling

Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  mic_stream_recorder: ^1.0.0

Then run:

flutter pub get

Quick Start #

import 'package:mic_stream_recorder/mic_stream_recorder.dart';

final recorder = MicStreamRecorder();

// Start recording
await recorder.startRecording();

// Listen to real-time amplitude
recorder.amplitudeStream.listen((amplitude) {
  print('Amplitude: ${(amplitude * 100).toInt()}%');
});

// Stop recording and get file path
final filePath = await recorder.stopRecording();
print('Recording saved: $filePath');

// Play the recording
await recorder.playRecording();

Detailed Usage #

Configuration #

Configure recording settings before starting:

// Configure with individual parameters
await recorder.configureRecording(
  sampleRate: 44100,     // 8000, 16000, 22050, 44100, 48000
  channels: 1,           // 1 (mono) or 2 (stereo)
  audioQuality: AudioQuality.high,  // min, low, medium, high, max
  bufferSize: 1024,      // 128, 256, 512, 1024, 2048, 4096
);

// Or use RecordingConfig object
const config = RecordingConfig(
  sampleRate: 44100,
  channels: 1,
  audioQuality: AudioQuality.high,
  bufferSize: 512,
);
await recorder.configureRecordingWithConfig(config);

Recording Control #

// Start recording (requests permission automatically)
await recorder.startRecording();

// Stop recording and get file path
String? filePath = await recorder.stopRecording();

// Check platform version
String? version = await recorder.getPlatformVersion();

Real-time Amplitude Monitoring #

Perfect for creating audio visualizations:

StreamSubscription? subscription;

subscription = recorder.amplitudeStream.listen(
  (double amplitude) {
    // amplitude is normalized between 0.0 and 1.0
    setState(() {
      _currentAmplitude = amplitude;
    });
  },
  onError: (error) => print('Amplitude error: $error'),
);

// Don't forget to cancel the subscription
subscription?.cancel();

Playback Control #

// Play the most recent recording
await recorder.playRecording();

// Play a specific file
await recorder.playRecording('/path/to/audio/file.m4a');

// Pause playback
await recorder.pausePlayback();

// Stop playback
await recorder.stopPlayback();

// Check if currently playing
bool isPlaying = await recorder.isPlaying();

Complete Example #

class RecordingWidget extends StatefulWidget {
  @override
  _RecordingWidgetState createState() => _RecordingWidgetState();
}

class _RecordingWidgetState extends State<RecordingWidget> {
  final _recorder = MicStreamRecorder();
  bool _isRecording = false;
  double _amplitude = 0.0;
  String? _recordingPath;
  StreamSubscription<double>? _amplitudeSubscription;

  @override
  void dispose() {
    _amplitudeSubscription?.cancel();
    super.dispose();
  }

  Future<void> _startRecording() async {
    try {
      await _recorder.configureRecording(
        sampleRate: 44100,
        audioQuality: AudioQuality.high,
      );
      
      await _recorder.startRecording();
      
      _amplitudeSubscription = _recorder.amplitudeStream.listen(
        (amplitude) => setState(() => _amplitude = amplitude),
      );
      
      setState(() => _isRecording = true);
    } catch (e) {
      print('Recording failed: $e');
    }
  }

  Future<void> _stopRecording() async {
    try {
      final path = await _recorder.stopRecording();
      _amplitudeSubscription?.cancel();
      
      setState(() {
        _isRecording = false;
        _amplitude = 0.0;
        _recordingPath = path;
      });
    } catch (e) {
      print('Stop recording failed: $e');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        // Amplitude visualization
        if (_isRecording)
          LinearProgressIndicator(
            value: _amplitude,
            backgroundColor: Colors.grey[300],
            valueColor: AlwaysStoppedAnimation<Color>(
              _amplitude > 0.7 ? Colors.red :
              _amplitude > 0.3 ? Colors.orange : Colors.green,
            ),
          ),
        
        // Recording button
        ElevatedButton(
          onPressed: _isRecording ? _stopRecording : _startRecording,
          child: Text(_isRecording ? 'Stop Recording' : 'Start Recording'),
        ),
        
        // Playback button
        if (_recordingPath != null)
          ElevatedButton(
            onPressed: () => _recorder.playRecording(_recordingPath),
            child: Text('Play Recording'),
          ),
      ],
    );
  }
}

Permissions #

Android #

Add the following permission to your android/app/src/main/AndroidManifest.xml:

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

iOS #

Add the following to your ios/Runner/Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>This app needs access to microphone to record audio.</string>

API Reference #

MicStreamRecorder #

AudioQuality #

• AudioQuality.min - 32 kbps
• AudioQuality.low - 64 kbps
• AudioQuality.medium - 96 kbps
• AudioQuality.high - 128 kbps
• AudioQuality.max - 192 kbps

Platform Support #

Technical Implementation #

• iOS: Uses AVAudioEngine for real-time processing and AVAudioRecorder for file recording
• Android: Uses MediaRecorder for recording and AudioRecord for amplitude monitoring
• Format: M4A containers with AAC encoding for optimal quality and file size
• Threading: Background processing for amplitude calculation with main thread updates
• Memory: Efficient buffer management and automatic resource cleanup

Contributing #

Contributions are welcome! Please feel free to submit a Pull Request.

Issues #

Please file any issues, bugs, or feature requests in the GitHub repository.

License #

This project is licensed under the MIT License - see the LICENSE file for details.

Author #

Yasin Arik

• GitHub: @yasinarik
• Email: [email protected]