Future<Sound> loadDataUrl(String dataUrl, [ SoundLoadOptions soundLoadOptions ])

Loads a sound from a data url.

Please be aware that browsers do support different kinds of audio types. You can get a list of supported types here: Sound.supportedTypes

var sound = await Sound.loadDataUrl("data:audio/mpeg;base64,<data>");
sound.play();

Source 

static Future<Sound> loadDataUrl(String dataUrl, [SoundLoadOptions soundLoadOptions]) {
  return new Future<Sound>.value(new MockSound._());
}