Play or stream sound and music with flutter_soloud

This recipe demonstrates how to integrate the flutter_soloud package into your Flutter application to play sound effects and background music with low latency. To get started using the package, follow these steps:

1. Add the package dependency
2. Initialize SoLoud
3. Load audio
4. Play audio
5. Control playback
6. Dispose of sound sources
7. [Optional] Stream audio

To add package:flutter_soloud as a dependency, use flutter pub add:

$ flutter pub add flutter_soloud

Before playing any audio, you need to initialize the SoLoud instance. You can also configure playback settings like sample rate, buffer size, and the number of channels.

import 'package:flutter_soloud/flutter_soloud.dart';
​
// Initialize with default settings
await SoLoud.instance.init();
​
// Or configure with custom settings
await SoLoud.instance.init(
  sampleRate: 44100,
  bufferSize: 2048,
  channels: Channels.stereo,
);

The flutter_soloud package supports various audio formats including MP3, WAV, OGG, and FLAC. You can load audio from different sources.

From a local file:

SoundProps sound = await SoLoud.instance.loadFile('path/to/sound.mp3');

From an app asset:

SoundProps sound = await SoLoud.instance.loadAsset('assets/sound.mp3');

From a network URL:

SoundProps sound = await SoLoud.instance.loadUrl(
  'https://example.com/sound.mp3',
  mode: LoadMode.memory,
);

From bytes in memory:

// Uint8List bytes = ...; // Your audio data
SoundProps sound = await SoLoud.instance.loadMem(
  'reference_name.mp3',
  bytes,
  mode: LoadMode.memory,
);

Once the audio is loaded, you can play it using SoLoud.instance.play. You can also configure gapless looping.

// Play the sound
var handle = await SoLoud.instance.play(sound);
​
// Play with gapless looping
handle = await SoLoud.instance.play(
  sound,
  looping: true,
  loopingStartAt: Duration(seconds: 1),
);

The play method returns a handle that references that particular instance of the sound being played. You can use this handle to control the playback.

With the handle returned from play, you can perform various actions such as pausing or resuming playback:

SoLoud.instance.pauseSwitch(handle); // Toggles pause state

Seek to a specific timestamp:

SoLoud.instance.seek(handle, Duration(seconds: 5));

Set playback speed:

SoLoud.instance.setRelativePlaySpeed(handle, 2.0); // Play twice as fast

Adjust playback volume:

SoLoud.instance.setVolume(handle, 0.5); // 50% volume

Fade the audio volume:

SoLoud.instance.fadeVolume(
  handle,
  0.0, // target volume
  Duration(seconds: 2), // fade duration
);

Stop playback:

await SoLoud.instance.stop(handle);

When you are finished with a sound source, remember to dispose it to free up resources.

await SoLoud.instance.disposeSource(sound);

The flutter_soloud package also supports streaming audio data in real-time.

Initialize and configure a buffer stream:

var stream = SoLoud.instance.setBufferStream(
  bufferingType: BufferingType.released,
  sampleRate: 24000,
  channels: Channels.mono,
  format: BufferType.s16le, // pcm16bits
);

Play the stream:

final handle = await SoLoud.instance.play(stream);

As your app receives audio data, add it to the stream:

// Uint8List audioChunk = ...; // Your audio data chunk
SoLoud.instance.addAudioDataStream(
  stream,
  audioChunk,
);

When you're done with the audio stream, mark it as complete:

SoLoud.instance.setDataIsEnded(stream);

For more detailed information and examples, visit the flutter_soloud package on pub.dev or check out the flutter_soloud Package of the Week video.