https://pub.dev/packages/flutter_fft
Warning: Currently works only on Android! This plugin makes use of platform channels, and only the Java/Android platform channel has been implemented.
The plugin was developed and tested in a Pixel 2 emulator, API 29. Does not work on iOS at the moment, due to the platform channel having yet to be implemented.
Minimum SDK version >= 24: You can update the minimum SDK requirements at "/android/app/build.gradle"
in the line minSdkVersion 16
.
The following needs to be added to your project's "android/app/src/main/AndroidManifest.xml"
:
<uses-permission android:name="android.permission.RECORD_AUDIO" />
What you can do with the plugin is very strict: Start recording, get data back from the platform channel, and stop recording.
There are many getters and setters for the processed and default data, which are going to be discussed further below.
Simple example:
import 'package:flutter/material.dart';
import 'package:flutter_fft/flutter_fft.dart';
void main() => runApp(Application());
class Application extends StatefulWidget {
@override
ApplicationState createState() => ApplicationState();
}
class ApplicationState extends State<Application> {
double frequency;
String note;
bool isRecording;
FlutterFft flutterFft = new FlutterFft();
@override
void initState() {
isRecording = flutterFft.getIsRecording;
frequency = flutterFft.getFrequency;
note = flutterFft.getNote;
super.initState();
_async();
}
@override
Widget build(BuildContext context) {
return MaterialApp(
title: "Simple flutter fft example",
theme: ThemeData.dark(),
color: Colors.blue,
home: Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
isRecording
? Text(
"Current note: $note",
style: TextStyle(
fontSize: 35,
),
)
: Text(
"None yet",
style: TextStyle(
fontSize: 35,
),
),
isRecording
? Text(
"Current frequency: ${frequency.toStringAsFixed(2)}",
style: TextStyle(
fontSize: 35,
),
)
: Text(
"None yet",
style: TextStyle(
fontSize: 35,
),
),
],
),
),
),
);
}
_async() async {
print("starting...");
await flutterFft.startRecorder();
setState(() => isRecording = flutterFft.getIsRecording);
flutterFft.onRecorderStateChanged.listen(
(data) => {
setState(
() => {
frequency = data[1],
note = data[2],
},
),
flutterFft.setNote = note,
flutterFft.setFrequency = frequency,
},
);
}
}
The following list displays the arrays content in the corresponding order:
- tolerance
- frequency
- note
- target
- distance
- octave
- nearestNote
- nearestTarget
- nearestDistance
- nearestOctave
- isOnPitch
- volume (in dB)
When we instantiate the plugin, a method channel variable is created, with the tag "com.slins.flutterfft/record"
.
This is the variable responsible for estabilishing a connection between Dart and the platform channel.
For the section below, it is assumed that the plugin was instantiated and stored in a variable called "flutterFft".
flutterFft.onRecorderStateChanged
- Stream that listens to the updates from the recorder..
flutterFft.startRecording()
- Starts recording using the data from the plugin's local instance. In other words, if you want to pass custom values as arguments, you have to set them inside the
flutterFft
instance before starting the recorder. i.e.flutterFft.setSampleRate = 22050
- Starts recording using the data from the plugin's local instance. In other words, if you want to pass custom values as arguments, you have to set them inside the
flutterFft.stopRecording()
- Stops recording.
Variable | Default Value | Type | Getter | Setter | Description |
---|---|---|---|---|---|
_tuning |
["E4", "B3", "G3", "D3", "A2", "E2"] |
List<String> |
flutterFft.getTuning |
flutterFft.setTuning |
Controller for the tuning target. Format: ["E4", "B3", "G3", "D3", "A2", "E2"] (The detected frequency is compared to these values in order to resolve the detection data.) |
_isRecording |
false |
bool |
flutterFft.getIsRecording |
flutterFft.setIsRecording |
Controller for the recorder state. |
_subscriptionDuration |
0.25 |
double |
flutterFft.getSubscriptionDuration |
flutterFft.setSubscriptionDuration |
Controller for the interval between platform channel function calls. |
_numChannels |
1 |
int |
flutterFft.getNumChannels |
flutterFft.setNumChannels |
Controller for the number of channels that gets passed to the pitch detector. |
_sampleRate |
44100 |
int |
flutterFft.getSampleRate |
flutterFft.setSampleRate |
Controller for the sample rate that gets passed to the pitch detector. |
_androidAudioSource |
AndroidAudioSource.MIC |
AndroidAudioSource |
flutterFft.getAndroidAudioSource |
flutterFft.setAndroidAudioSource |
Controller for the audio source. (Microphone, etc.) |
_tolerance |
1.00 |
double |
flutterFft.getTolerance |
flutterFft.setTolerance |
Controller for the tolerance. (How far apart can the current frequency from the target frequency in order to be considered on pitch) |
_frequency |
0 |
double |
flutterFft.getFrequency |
flutterFft.setFrequency |
Controller for the frequency. |
_note |
"" |
String |
flutterFft.getNote |
flutterFft.setNote |
Controller for the note |
_target |
0 |
double |
flutterFft.getTarget |
flutterFft.setTarget |
Controller for the target frequency. (Based on the current selected tuning, calculate the nearest frequency in tune to be considered as the target, i.e: IF currentNote == A && A.frequency.distanceToB IS SmallestTargetDistance -> _target = A.frequency.distanceToB ) |
_distance |
0 |
double |
flutterFft.getDistance |
flutterFft.setDistance |
Controller for the distance between the current frequency and the target frequency. |
_octave |
0 |
int |
flutterFft.getOctave |
flutterFft.setOctave |
Controller for the detected octave. |
_nearestNote |
"" |
String |
flutterFft.getNearestNote |
flutterFft.setNearestNote |
Controller for nearest note. (Based on the current note) |
_nearestTarget |
0 |
double |
flutterFft.getNearestTarget |
flutterFft.setNearestTarget |
Controller for nearest target. (Second smallest distance, as the smallest distance is already _target ) |
_nearestDistance |
0 |
double |
flutterFft.getNearestDistance |
flutterFft.setNearestDistance |
Controller for nearest distance. (Second smallest distance) |
_nearestOctave |
0 |
int |
flutterFft.getNearestOctave |
flutterFft.setNearestOctave |
Controller for nearest octave. (Based on the "nearest" data) |
_isOnPitch |
false |
bool |
flutterFft.getIsOnPitch |
flutterFft.setIsOnPitch |
Controller for the pitch |