Node.js音频播放器

Question

我基本上想要互相播放一系列mp3文件。 它应该不是很难，但我很难保持解码器和扬声器通道打开，以便在播放一首歌后输入新的mp3数据。 这是我到目前为止的一个浓缩版本，播放一个mp3文件。

var audioOptions = {channels: 2, bitDepth: 16, sampleRate: 44100};

// Create Decoder and Speaker
var decoder = lame.Decoder();
var speaker = new Speaker(audioOptions);

// My Playlist
var songs = ['samples/Piano11.mp3','samples/Piano12.mp3','samples/Piano13.mp3'];

// Read the first file
var inputStream = fs.createReadStream(songs[0]);

// Pipe the read data into the decoder and then out to the speakers
inputStream.pipe(decoder).pipe(speaker);

speaker.on('flush', function(){
  // Play next song
});

我正在使用TooTallNate的模块node-lame （用于解码）和node-speaker （用于通过扬声器输出音频）。

Answer 1

没有任何关于你提到的模块的经验，但我认为你每次想要播放一首歌时都需要重新打开扬声器（因为你将解码后的音频传输给它，一旦解码完成就会关闭它）。

您可以将代码重写为此类（未经测试）;

var audioOptions = {channels: 2, bitDepth: 16, sampleRate: 44100};

// Create Decoder and Speaker
var decoder = lame.Decoder();

// My Playlist
var songs = ['samples/Piano11.mp3','samples/Piano12.mp3','samples/Piano13.mp3'];

// Recursive function that plays song with index 'i'.
function playSong(i) {
  var speaker     = new Speaker(audioOptions);
  // Read the first file
  var inputStream = fs.createReadStream(songs[i]);
  // Pipe the read data into the decoder and then out to the speakers
  inputStream.pipe(decoder).pipe(speaker);
  speaker.on('flush', function(){
    // Play next song, if there is one.
    if (i < songs.length - 1)
      playSong(i + 1);
  });
}

// Start with the first song.
playSong(0);

另一个解决方案（我更喜欢的是）使用非常好的异步模块：

var async = require('async');
...
async.eachSeries(songs, function(song, done) {
  var speaker     = new Speaker(audioOptions);
  var inputStream = fs.createReadStream(song);

  inputStream.pipe(decoder).pipe(speaker);

  speaker.on('flush', function() {
    // signal async that it should process the next song in the array  
    done();
  });
});