Audio bitrate support (#1439)

* Audio bitrate support

Note: not implemented for VoiceBroadcasts

* Fix default args, auto bitrate

* Late night typos are the best

* Changes bitrate to kbps for VoiceChannel stuff

* Add methods to manipulate bitrate while encoding

src/client/voice/VoiceBroadcast.js

@@ -143,8 +143,8 @@ class VoiceBroadcast extends VolumeInterface {
    *  })
    *  .catch(console.error);
    */
-  playStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes, stream };
+  playStream(stream, options = {}) {
+    this.setVolume(options.volume || 1);
     return this._playTranscodable(stream, options);
   }
 
@@ -164,19 +164,17 @@ class VoiceBroadcast extends VolumeInterface {
    *  })
    *  .catch(console.error);
    */
-  playFile(file, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
+  playFile(file, options = {}) {
+    this.setVolume(options.volume || 1);
     return this._playTranscodable(`file:${file}`, options);
   }
 
   _playTranscodable(media, options) {
-    OpusEncoders.guaranteeOpusEngine();
-
     this.killCurrentTranscoder();
     const transcoder = this.prism.transcode({
       type: 'ffmpeg',
       media,
-      ffmpegArguments: ffmpegArguments.concat(['-ss', String(options.seek)]),
+      ffmpegArguments: ffmpegArguments.concat(['-ss', String(options.seek || 0)]),
     });
     /**
      * Emitted whenever an error occurs.
@@ -206,31 +204,28 @@ class VoiceBroadcast extends VolumeInterface {
   }
 
   /**
-   * Plays a stream of 16-bit signed stereo PCM at 48KHz.
+   * Plays a stream of 16-bit signed stereo PCM.
    * @param {ReadableStream} stream The audio stream to play
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {VoiceBroadcast}
    */
-  playConvertedStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    OpusEncoders.guaranteeOpusEngine();
-
+  playConvertedStream(stream, options = {}) {
     this.killCurrentTranscoder();
-    const options = { seek, volume, passes, stream };
-    this.currentTranscoder = { options };
+    this.setVolume(options.volume || 1);
+    this.currentTranscoder = { options: { stream } };
     stream.once('readable', () => this._startPlaying());
     return this;
   }
 
   /**
-   * Plays an Opus encoded stream at 48KHz.
+   * Plays an Opus encoded stream.
    * <warn>Note that inline volume is not compatible with this method.</warn>
    * @param {ReadableStream} stream The Opus audio stream to play
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {StreamDispatcher}
    */
-  playOpusStream(stream, { seek = 0, passes = 1 } = {}) {
-    const options = { seek, passes, stream };
-    this.currentTranscoder = { options, opus: true };
+  playOpusStream(stream) {
+    this.currentTranscoder = { options: { stream }, opus: true };
     stream.once('readable', () => this._startPlaying());
     return this;
   }
@@ -241,8 +236,9 @@ class VoiceBroadcast extends VolumeInterface {
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {VoiceBroadcast}
    */
-  playArbitraryInput(input, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes, input };
+  playArbitraryInput(input, options = {}) {
+    this.setVolume(options.volume || 1);
+    options.input = input;
     return this._playTranscodable(input, options);
   }
 

src/client/voice/VoiceConnection.js

@@ -431,6 +431,8 @@ class VoiceConnection extends EventEmitter {
    * @property {number} [seek=0] The time to seek to
    * @property {number} [volume=1] The volume to play at
    * @property {number} [passes=1] How many times to send the voice packet to reduce packet loss
+   * @property {number|string} [bitrate=48000] The bitrate (quality) of the audio.
+   * If set to 'auto', the voice channel's bitrate will be used
    */
 
   /**
@@ -481,7 +483,7 @@ class VoiceConnection extends EventEmitter {
   }
 
   /**
-   * Plays a stream of 16-bit signed stereo PCM at 48KHz.
+   * Plays a stream of 16-bit signed stereo PCM.
    * @param {ReadableStream} stream The audio stream to play
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {StreamDispatcher}
@@ -491,7 +493,7 @@ class VoiceConnection extends EventEmitter {
   }
 
   /**
-   * Plays an Opus encoded stream at 48KHz.
+   * Plays an Opus encoded stream.
    * <warn>Note that inline volume is not compatible with this method.</warn>
    * @param {ReadableStream} stream The Opus audio stream to play
    * @param {StreamOptions} [options] Options for playing the stream
@@ -504,6 +506,7 @@ class VoiceConnection extends EventEmitter {
   /**
    * Plays a voice broadcast.
    * @param {VoiceBroadcast} broadcast The broadcast to play
+   * @param {StreamOptions} [options] Options for playing the stream
    * @returns {StreamDispatcher}
    * @example
    * // Play a broadcast
@@ -512,8 +515,8 @@ class VoiceConnection extends EventEmitter {
    *   .playFile('./test.mp3');
    * const dispatcher = voiceConnection.playBroadcast(broadcast);
    */
-  playBroadcast(broadcast) {
-    return this.player.playBroadcast(broadcast);
+  playBroadcast(broadcast, options) {
+    return this.player.playBroadcast(broadcast, options);
   }
 
   /**

src/client/voice/dispatcher/StreamDispatcher.js

@@ -119,6 +119,16 @@ class StreamDispatcher extends VolumeInterface {
     this.emit('speaking', value);
   }
 
+
+  /**
+   * Set the bitrate of the current Opus encoder.
+   * @param {number} bitrate New bitrate, in kbps.
+   * If set to 'auto', the voice channel's bitrate will be used
+   */
+  setBitrate(bitrate) {
+    this.player.setBitrate(bitrate);
+  }
+
   sendBuffer(buffer, sequence, timestamp, opusPacket) {
     opusPacket = opusPacket || this.player.opusEncoder.encode(buffer);
     const packet = this.createPacket(sequence, timestamp, opusPacket);

src/client/voice/opus/BaseOpusEngine.js

@@ -4,21 +4,38 @@
  */
 class BaseOpus {
   /**
-   * @param {Object} [options] The options to apply to the Opus engine
-   * @param {boolean} [options.fec] Whether to enable forward error correction (defaults to false)
-   * @param {number} [options.plp] The expected packet loss percentage (0-1 inclusive, defaults to 0)
+   * @param {Object} [options] The options to apply to the Opus engine.
+   * @param {number} [options.bitrate=48] The desired bitrate (kbps).
+   * @param {boolean} [options.fec=false] Whether to enable forward error correction.
+   * @param {number} [options.plp=0] The expected packet loss percentage.
    */
-  constructor(options = {}) {
+  constructor({ bitrate = 48, fec = false, plp = 0 } = {}) {
     this.ctl = {
+      BITRATE: 4002,
       FEC: 4012,
       PLP: 4014,
     };
 
-    this.options = options;
+    this.samplingRate = 48000;
+    this.channels = 2;
+
+    /**
+     * The desired bitrate (kbps)
+     * @type {number}
+     */
+    this.bitrate = bitrate;
+
+    /**
+     * Miscellaneous Opus options
+     * @type {Object}
+     */
+    this.options = { fec, plp };
   }
 
   init() {
     try {
+      this.setBitrate(this.bitrate);
+
       // Set FEC (forward error correction)
       if (this.options.fec) this.setFEC(this.options.fec);
 

src/client/voice/opus/NodeOpusEngine.js

@@ -10,10 +10,14 @@ class NodeOpusEngine extends OpusEngine {
     } catch (err) {
       throw err;
     }
-    this.encoder = new opus.OpusEncoder(48000, 2);
+    this.encoder = new opus.OpusEncoder(this.samplingRate, this.channels);
     super.init();
   }
 
+  setBitrate(bitrate) {
+    this.encoder.applyEncoderCTL(this.ctl.BITRATE, Math.min(128, Math.max(16, bitrate)) * 1000);
+  }
+
   setFEC(enabled) {
     this.encoder.applyEncoderCTL(this.ctl.FEC, enabled ? 1 : 0);
   }

src/client/voice/opus/OpusEngineList.js

@@ -3,8 +3,6 @@ const list = [
   require('./OpusScriptEngine'),
 ];
 
-let opusEngineFound;
-
 function fetch(Encoder, engineOptions) {
   try {
     return new Encoder(engineOptions);
@@ -25,10 +23,9 @@ exports.fetch = engineOptions => {
     const fetched = fetch(encoder, engineOptions);
     if (fetched) return fetched;
   }
-  return null;
-};
 
 exports.guaranteeOpusEngine = () => {
   if (typeof opusEngineFound === 'undefined') opusEngineFound = Boolean(exports.fetch());
   if (!opusEngineFound) throw new Error('Couldn\'t find an Opus engine.');
+  throw new Error('OPUS_ENGINE_MISSING');
 };

src/client/voice/opus/OpusScriptEngine.js

@@ -10,10 +10,14 @@ class OpusScriptEngine extends OpusEngine {
     } catch (err) {
       throw err;
     }
-    this.encoder = new OpusScript(48000, 2);
+    this.encoder = new OpusScript(this.samplingRate, this.channels);
     super.init();
   }
 
+  setBitrate(bitrate) {
+    this.encoder.encoderCTL(this.ctl.BITRATE, Math.min(128, Math.max(16, bitrate)) * 1000);
+  }
+
   setFEC(enabled) {
     this.encoder.encoderCTL(this.ctl.FEC, enabled ? 1 : 0);
   }

src/client/voice/player/AudioPlayer.js

@@ -30,11 +30,6 @@ class AudioPlayer extends EventEmitter {
      * @type {Prism}
      */
     this.prism = new Prism();
-    /**
-     * The opus encoder that the player uses
-     * @type {NodeOpusEngine|OpusScriptEngine}
-     */
-    this.opusEncoder = OpusEncoders.fetch();
     this.streams = new Collection();
     this.currentStream = {};
     this.streamingData = {
@@ -67,6 +62,7 @@ class AudioPlayer extends EventEmitter {
 
   destroy() {
     if (this.opusEncoder) this.opusEncoder.destroy();
+    this.opusEncoder = null;
   }
 
   destroyCurrentStream() {
@@ -83,13 +79,25 @@ class AudioPlayer extends EventEmitter {
     this.currentStream = {};
   }
 
-  playUnknownStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    OpusEncoders.guaranteeOpusEngine();
-    const options = { seek, volume, passes };
+  /**
+   * Set the bitrate of the current Opus encoder.
+   * @param {number} value New bitrate, in kbps.
+   * If set to 'auto', the voice channel's bitrate will be used
+   */
+  setBitrate(value) {
+    if (!value) return;
+    if (!this.opusEncoder) return;
+    const bitrate = value === 'auto' ? this.voiceConnection.channel.bitrate : value;
+    this.opusEncoder.setBitrate(bitrate);
+  }
+
+  playUnknownStream(stream, options = {}) {
+    this.destroy();
+    this.opusEncoder = OpusEncoders.fetch(options);
     const transcoder = this.prism.transcode({
       type: 'ffmpeg',
       media: stream,
-      ffmpegArguments: ffmpegArguments.concat(['-ss', String(seek)]),
+      ffmpegArguments: ffmpegArguments.concat(['-ss', String(options.seek || 0)]),
     });
     this.destroyCurrentStream();
     this.currentStream = {
@@ -105,9 +113,10 @@ class AudioPlayer extends EventEmitter {
     return this.playPCMStream(transcoder.output, options, true);
   }
 
-  playPCMStream(stream, { seek = 0, volume = 1, passes = 1 } = {}, fromUnknown = false) {
-    OpusEncoders.guaranteeOpusEngine();
-    const options = { seek, volume, passes };
+  playPCMStream(stream, options = {}, fromUnknown = false) {
+    this.destroy();
+    this.opusEncoder = OpusEncoders.fetch(options);
+    this.setBitrate(options.bitrate);
     const dispatcher = this.createDispatcher(stream, options);
     if (fromUnknown) {
       this.currentStream.dispatcher = dispatcher;
@@ -122,8 +131,8 @@ class AudioPlayer extends EventEmitter {
     return dispatcher;
   }
 
-  playOpusStream(stream, { seek = 0, passes = 1 } = {}) {
-    const options = { seek, passes, opus: true };
+  playOpusStream(stream, options = {}) {
+    options.opus = true;
     this.destroyCurrentStream();
     const dispatcher = this.createDispatcher(stream, options);
     this.currentStream = {
@@ -134,8 +143,7 @@ class AudioPlayer extends EventEmitter {
     return dispatcher;
   }
 
-  playBroadcast(broadcast, { volume = 1, passes = 1 } = {}) {
-    const options = { volume, passes };
+  playBroadcast(broadcast, options) {
     this.destroyCurrentStream();
     const dispatcher = this.createDispatcher(broadcast, options);
     this.currentStream = {
@@ -148,7 +156,9 @@ class AudioPlayer extends EventEmitter {
     return dispatcher;
   }
 
-  createDispatcher(stream, options) {
+  createDispatcher(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    const options = { seek, volume, passes };
+
     const dispatcher = new StreamDispatcher(this, stream, options);
     dispatcher.on('end', () => this.destroyCurrentStream());
     dispatcher.on('error', () => this.destroyCurrentStream());

src/structures/VoiceChannel.js

@@ -25,7 +25,7 @@ class VoiceChannel extends GuildChannel {
      * The bitrate of this voice channel
      * @type {number}
      */
-    this.bitrate = data.bitrate;
+    this.bitrate = data.bitrate * 0.001;
 
     /**
      * The maximum amount of users allowed in this channel - 0 means unlimited.
@@ -76,16 +76,17 @@ class VoiceChannel extends GuildChannel {
   }
 
   /**
-   * Sets the bitrate of the channel.
+   * Sets the bitrate of the channel (in kbps).
    * @param {number} bitrate The new bitrate
    * @returns {Promise<VoiceChannel>}
    * @example
    * // Set the bitrate of a voice channel
-   * voiceChannel.setBitrate(48000)
-   *  .then(vc => console.log(`Set bitrate to ${vc.bitrate} for ${vc.name}`))
+   * voiceChannel.setBitrate(48)
+   *  .then(vc => console.log(`Set bitrate to ${vc.bitrate}kbps for ${vc.name}`))
    *  .catch(console.error);
    */
   setBitrate(bitrate) {
+    bitrate *= 1000;
     return this.edit({ bitrate });
   }