start work with broadcast streams

src/client/voice/VoiceBroadcast.js

@@ -0,0 +1,85 @@
+const EventEmitter = require('events').EventEmitter;
+const Prism = require('prism-media');
+
+const ffmpegArguments = [
+  '-analyzeduration', '0',
+  '-loglevel', '0',
+  '-f', 's16le',
+  '-ar', '48000',
+  '-ac', '2',
+];
+
+class VoiceBroadcast extends EventEmitter {
+  constructor(client) {
+    super();
+    this.client = client;
+    this.dispatchers = [];
+    this.prism = new Prism();
+    this.currentTranscoder = null;
+  }
+
+  get _playableStream() {
+    if (!this.currentTranscoder) return null;
+    return this.currentTranscoder.transcoder.output || this.currentTranscoder.options.stream;
+  }
+
+  registerDispatcher(dispatcher) {
+    if (!this.dispatchers.includes(dispatcher)) this.dispatchers.push(dispatcher);
+  }
+
+  killCurrentTranscoder() {
+    if (this.currentTranscoder) {
+      if (this.currentTranscoder.transcoder) this.currentTranscoder.transcoder.kill();
+      this.currentTranscoder = null;
+    }
+  }
+
+  playStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    const options = { seek, volume, passes };
+    options.stream = stream;
+    return this._playTranscodable(stream, options);
+  }
+
+  playFile(file, { seek = 0, volume = 1, passes = 1 } = {}) {
+    const options = { seek, volume, passes };
+    return this._playTranscodable(file, options);
+  }
+
+  _playTranscodable(media, options) {
+    this.killCurrentTranscoder();
+    const transcoder = this.prism.transcode({
+      type: 'ffmpeg',
+      media,
+      ffmpegArguments: ffmpegArguments.concat(['-ss', String(options.seek)]),
+    });
+    transcoder.once('error', e => this.emit('error', e));
+    transcoder.once('end', () => this.killCurrentTranscoder());
+    this.currentTranscoder = {
+      transcoder,
+      options,
+    };
+    transcoder.output.once('readable', () => this._startPlaying());
+    return this;
+  }
+
+  playConvertedStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    this.killCurrentTranscoder();
+    const options = { seek, volume, passes, stream };
+    this.currentTranscoder = { options };
+    stream.once('readable', () => this._startPlaying());
+    return this;
+  }
+
+  _startPlaying() {
+    if (!this._playableStream) return;
+    const stream = this._playableStream;
+    const buffer = stream.read(1920 * 2);
+
+    for (const dispatcher of this.dispatchers) {
+      setImmediate(() => dispatcher.process(buffer, true));
+    }
+    setTimeout(this._startPlaying.bind(this), 20);
+  }
+}
+
+module.exports = VoiceBroadcast;