flutter_recorder 0.9.2 
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marcobavagnoli.comA low-level audio recorder plugin which uses miniaudio as backend. Detect silence and save to WAV audio file. Audio wave, FFT and volume level can be get in real-time.
A low-level audio recorder plugin that uses miniaudio as the backend and supports all the platforms. It can detect silence and save to a WAV audio file. Audio wave and FFT data can be obtained in real-time as for the volume level.
| Linux | Windows | Android | MacOS (under test) | iOS (under test) | web (WASM compatible) |
|---|---|---|---|---|---|
| 💙 | 💙 | 💙 | 💙 | 💙 | 💙 |
Note: not yet available on pub.dev
🌟 Key Features: #
- 🖥️ Cross-platform: Supports Linux, Windows, Android, MacOS, iOS, and web.
- ⚡ High performance: Built using the fast and efficient miniaudio C library with FFI.
- 🎙️ WAV Recording with Pause: Record in WAV format with pause functionality.
- ⚙️ Choose Data Type: samplerate, mono or stereo, audio format (u8, s8, s16le, s24le, s32le or f32le).
- 🎛️ Device Flexibility: Choose your recording device.
- 📢 Stream audio data: Listen to PCM audio data stream.
- 🔇 Silence Detection: Automatically detects silence via callback or Stream.
- 📊 Customizable Silence Threshold: Define what’s considered “silence” for your recordings.
- ⏱️ Adjustable Pause Timing: Set how long silence lasts before pausing, and how soon to resume recording.
- 🔊 Real-time Audio Metrics: Access volume, audio wave, and FFT data in real-time.
A web example compiled in WASM.
🚀 Setup Permissions #
After setting up permission for you Android, MacOS or iOS, in your app, you will need to ask for permission to use the microphonem maybe using permission_handler plugin. https://pub.dev/packages/permission_handler
Android
Add the permission in the AndroidManifest.xml.
<uses-permission android:name="android.permission.RECORD_AUDIO" />
MacOS, iOS
Add the permission in Runner/Info.plist.
<key>NSMicrophoneUsageDescription</key>
<string>Some message to describe why you need this permission</string>
Web
Add this in web/index.html under the <head> tag.
<script src="assets/packages/flutter_recorder/web/libflutter_recorder_plugin.js" defer></script>
🛠️ Usage Example #
import 'package:permission_handler/permission_handler.dart';
[...]
/// If you are running on Android, MacOS or iOS, ask the permission to use the microphone:
if (defaultTargetPlatform == TargetPlatform.android ||
defaultTargetPlatform == TargetPlatform.iOS ||
defaultTargetPlatform == TargetPlatform.macOS) {
Permission.microphone.request().isGranted.then((value) async {
if (!value) {
await [Permission.microphone].request();
}
});
/// Initialize the capture device and start it:
try {
Recorder.instance.init();
Recorder.instance.start();
} on Exception catch (e) {
debugPrint('init() error: $e\n');
}
/// On Web platform it is better to initialize and wait the user to give
/// mic permission. Then use `start()` when it's needed.
//Start recording:
Recorder.instance.startRecording(completeFilePath: 'audioCompleteFilenameWithPath.wav`);
/// Stop recording:
Recorder.instance.stopRecording();
Tip: Use Recorder.instance.listCaptureDevices() to see available devices and pass an optional deviceID to init().
Tip2: Use the format, sampleRate and channels with the init() method to define recorder parameters.
Tip3: When recording with silence detection and want to record a little bit before the threshold db is reached, use the setSecondsOfAudioToWriteBefore() method.
🔇 Silence Detection Example #
Want to skip the silence? Here’s how to configure it:
Recorder.instance.setSilenceDetection(
enable: true,
onSilenceChanged: (isSilent, decibel) {
/// Here you can check if silence is changed.
/// Or you can do the same thing with the Stream
/// [Recorder.instance.silenceChangedEvents]
},
);
/// the silence threshold in dB. A volume under this value is considered to be silence.
Recorder.instance.setSilenceThresholdDb(-27);
/// the value in seconds of silence after which silence is considered as such.
Recorder.instance.setSilenceDuration(0.5);
/// Set seconds of audio to write before starting recording again after silence.
Recorder.instance.setSecondsOfAudioToWriteBefore(0.0);
📊 Audio, FFT, and Volume Data #
You can also access raw audio data and volume information like this:
/// Get the current volume in dB in the [-100, 0] range.
double volume = Recorder.instance.getVolumeDb();
/// Return a 256 float array containing wave data in the range [-1.0, 1.0] not clamped.
Float32List waveAudio = Recorder.instance.getWave();
/// Return a 256 float array containing FFT data in the range [-1.0, 1.0] not clamped.
Float32List fftAudio = Recorder.instance.getFft();
NOTE: this is only available when initializing the recorder with PCMFormat.f32le format.
📢 Audio data stream #
/// Listen to audio data stream. The data is received in Uint8List.
Recorder.instance.uint8ListStream.listen((data) {
/// the [data] is of type `AudioDataContainer` and, whatever format is passed to
/// the `init()` method, it is available with [data.rawData] which is of `Uint8List`
/// type. This is useful if we want to write into a file.
/// It is possible to convert audio data to the desired format using one of the
/// `data.to[*]List` methods. Be aware that the conversion is compute expensive and
/// should be avoided if possible initializing the recorder with the format
/// desired.
});
/// Start streaming:
Recorder.instance.startStreamingData();
/// Stop streaming:
Recorder.instance.stopStreamingData();
Metadata
Publisher
Metadata
A low-level audio recorder plugin which uses miniaudio as backend. Detect silence and save to WAV audio file. Audio wave, FFT and volume level can be get in real-time.
Repository (GitHub)
View/report issues
Topics
Documentation
License
Apache-2.0 (license)
Dependencies
ffi, flutter, meta, plugin_platform_interface, web
