anarchuser / mic_stream

Flutter plugin to get an infinite audio stream from the microphone

mic_stream: 0.7.1

[Flutter Plugin] Provides a tool to get the microphone input as 8 or 16 bit PCM Stream. 32 bit and floating point PCM are experimental WIP.

About mic_stream:

As Flutter still lacks some functionality, this plugin aims to provide the possibility to easily get an audio stream from the microphone of mobile devices.

How to use:

The plugin mainly provides one method to provide a raw audio stream:

Stream<UInt8List> MicStream.microphone({options})

and a StreamTransformer to provide a Stream of individual samples (not lists of samples):

MicStream.toSampleStream

that you can use to transform your mic stream:

stream.transform(MicStream.toSampleStream)

Listening to this stream starts the audio recorder while cancelling the subscription stops the stream.

Available options are as follows:

audioSource: AudioSource      // The microphone you want to record from
sampleRate: int               // The amount of data points to record per second
channelConfig: ChannelConfig  // Mono or Stereo
audioFormat: AudioFormat      // 8 bit PCM or 16 bit PCM. Other formats are not yet supported

Some configuration options are platform dependent and can differ from the originally configured ones. You can check the real values using:

Future<int> sampleRate = await MicStream.sampleRate;
Future<int> bitDepth = await MicStream.bitDepth;
Future<int> bufferSize = await MicStream.bufferSize;

Permissions

Make sure you have microphone recording permissions enabled for your project. To do so, add this line to the AndroidManifest.xml:

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

In the Info.plist:

<key>NSMicrophoneUsageDescription</key>
<string>Microphone access required</string>

You can disable the permission request dialogue by calling MicStream.shouldRequestPermission(false) This will lead to an error if no permission to record audio has been requested, though.

For MacOS:

Open macos/Runner.xcworkspace click Runner -> Signing & Capabilities -> Check "Audio Input"

Example:

// Init a new Stream
Stream<List<int>> stream = await MicStream.microphone(sampleRate: 44100);

// Start listening to the stream
StreamSubscription<List<int>> listener = stream.listen((samples) => print(samples));

// Transform the stream and print each sample individually
stream.transform(MicStream.toSampleStream).listen(print);

// Cancel the subscription
listener.cancel()

Note: This plugin is still under development, and some APIs might not be available yet. Feedback and Pull Requests are most welcome!