minisound

A high-level real-time audio playback library based on miniaudio. The library offers basic functionality and quite low latency. Not really suitable for big sounds right now. Supports MP3, WAV and FLAC formats.

Run make help from the root project directory to get started.

Platform support

Getting started on the web

While the main script is quite large, there are a loader script provided. Include it in the web/index.html file like this

  <script src="https://github.com/DaniilAlpha/minisound/raw/master/assets/packages/minisound_web/js/minisound_web.loader.js"></script>

It is highly recommended NOT to make the script defer, as loading may not work properly. Also, it is very small (only 18 lines).

And at the bottom, at the body's <script> do like this

window.addEventListener(
  'load',
  // ADD 'async'
  async function (ev) {
      // ADD THIS LINE AT THE TOP
      await _minisound.loader.load();

      // LEAVE THE REST IN PLACE
      // Download main.dart.js
      _flutter.loader.loadEntrypoint({
        serviceWorker: {
          serviceWorkerVersion: serviceWorkerVersion
        },
        onEntrypointLoaded: function (engineInitializer) {
          engineInitializer.initializeEngine().then(function (appRunner) {
            appRunner.runApp();
          });
        }
      });
    }
  );

Minisound uses SharedArrayBuffer feature, so you should enable cross-origin isolation on your site.

Usage

To use this plugin, add minisound as a dependency in your pubspec.yaml file.

import "package:minisound/minisound.dart" as minisound;

void main() {
  final engine = minisound.Engine();

  // this method takes an update period in milliseconds as an argument, which
  // determines the length of the latency (does not currently affect the web)
  await engine.init(); 

  // there is also a 'loadSound' method to load a sound from the Uint8List
  final sound = await engine.loadSoundAsset("asset/path.ext");
  sound.volume = 0.5;

  // this may cause a MinisoundPlatformException to be thrown on the web
  // before any user interaction due to the autoplay policy
  await engine.start(); 

  sound.play();

  await Future.delayed(sound.duration*.5);

  sound.pause(); // this method saves sound position
  sound.stop(); // but this does not

  final loopDelay=Duratoin(seconds: 1);
  sound.playLooped(delay: loopDelay); // sound will be looped with one second period

  await Future.delayed((sound.duration + loopDelay) * 5); // sound duration does not account loop delay

  sound.stop();

  // it is recommended to unload sounds manually to prevent memory leaks
  sound.unload(); 

  // the engine and all loaded sounds will be automatically disposed when 
  // engine gets garbage-collected
}

Recorder Example

import "package:minisound/minisound.dart" as minisound;

void main() async {
  final recorder = minisound.Recorder();

  // Initialize the recorder's engine
  await recorder.initEngine();

  // Initialize the recorder for streaming
  await recorder.initStream(
    sampleRate: 48000,
    channels: 1,
    format: minisound.AudioFormat.float32,
    bufferLenS: 5,
  );

  // Start recording
  recorder.start();

  // Wait for some time while recording
  await Future.delayed(Duration(seconds: 5));

  // Stop recording
  recorder.stop();

  // Get the recorded buffer
  final buffer = recorder.getBuffer(recorder.availableFloatCount);

  // Process the recorded buffer as needed
  // ...

  // Dispose of the recorder resources
  recorder.dispose();
}

Generator Example

import "package:minisound/minisound.dart" as minisound;

void main() async {
  final generator = minisound.Generator();

  // Initialize the generator's engine
  await generator.initEngine();

  // Initialize the generator
  await generator.init(
    minisound.AudioFormat.float32,
    2,
    48000,
    5,
  );

  // Set the waveform type, frequency, and amplitude
  generator.setWaveform(minisound.WaveformType.sine, 440.0, 0.5);

  // Set the noise type, seed, and amplitude
  generator.setNoise(minisound.NoiseType.white, 0, 0.2);

  // Start the generator
  generator.start();

  // Generate and process audio data in a loop
  while (true) {
    final buffer = generator.getBuffer(generator.availableFloatCount);

    // Process the generated buffer as needed
    // ...

    await Future.delayed(Duration(milliseconds: 100));
  }

  // Stop the generator
  generator.stop();

  // Dispose of the generator resources
  generator.dispose();
}

Building the project

A Makefile is provided with recipes to build the project and ease development. Type make help to see a list of available commands.

To manually build the project, follow these steps:

1. Initialize the submodules:

   git submodule update --init --recursive

2. Make and/or Navigate to the minisound_ffi/src/build directory:

   cd minisound_ffi/src/build

3. Run the following commands to build the project using emcmake and cmake:

   emcmake cmake ..
   cmake --build .

   If you want to build the native version, encounter issues or want to start fresh, clean the build folder and rerun the cmake commands:

   rm -rf *
   cmake ..
   cmake --build .

4. For development work, it's useful to run ffigen from the minisound_ffi directory:

   cd minisound_ffi
   dart run ffigen

TODO

• [x] Fix non-intuitiveness of pausing and stopping, then playing again looped sounds
• [x] Exclude emscripten build cache from git.
• [ ] Stop crash when no devices found for playback or capture
• [ ] Extract buffer stuff to unified AV Buffer packages dart and C.
• [ ] Automate local web deployment with strict origin flags for local testing.
• [x] Create a makefile.
• [ ] Document dependencies for building.
• [ ] Switch engine init to state machine.