Added Opus stream support, added volume interface (#1102)

* Added opus stream support, added volume interface

* Remove setImmediate

* Fix weird syntax error

* Most useless commit ever

You're welcome, @PgBiel

* Fix potential memory leak with OpusScript

Emscripten has the tendency to not free resources even when the Opus engine instance has been garbage collected. Thanks to @abalabahaha for pointing this out.

* Typo

* VoiceReceiver.destroy: destroy opus encoder

src/client/voice/VoiceBroadcast.js

@@ -1,4 +1,4 @@
-const EventEmitter = require('events').EventEmitter;
+const VolumeInterface = require('./util/VolumeInterface');
 const Prism = require('prism-media');
 const OpusEncoders = require('./opus/OpusEngineList');
 const Collection = require('../../util/Collection');
@@ -15,7 +15,7 @@ const ffmpegArguments = [
  * A voice broadcast can be played across multiple voice connections for improved shared-stream efficiency.
  * @extends {EventEmitter}
  */
-class VoiceBroadcast extends EventEmitter {
+class VoiceBroadcast extends VolumeInterface {
   constructor(client) {
     super();
     /**
@@ -51,55 +51,12 @@ class VoiceBroadcast extends EventEmitter {
     return d;
   }
 
-  applyVolume(buffer, volume = this._volume) {
-    if (volume === 1) return buffer;
-
-    const out = Buffer.alloc(buffer.length);
-    for (let i = 0; i < buffer.length; i += 2) {
-      if (i >= buffer.length - 1) break;
-      const uint = Math.min(32767, Math.max(-32767, Math.floor(volume * buffer.readInt16LE(i))));
-      out.writeInt16LE(uint, i);
-    }
-
-    return out;
-  }
-
-  /**
-   * Sets the volume relative to the input stream - i.e. 1 is normal, 0.5 is half, 2 is double.
-   * @param {number} volume The volume that you want to set
-   */
-  setVolume(volume) {
-    this._volume = volume;
-  }
-
-  /**
-   * Set the volume in decibels
-   * @param {number} db The decibels
-   */
-  setVolumeDecibels(db) {
-    this.setVolume(Math.pow(10, db / 20));
-  }
-
-  /**
-   * Set the volume so that a perceived value of 0.5 is half the perceived volume etc.
-   * @param {number} value The value for the volume
-   */
-  setVolumeLogarithmic(value) {
-    this.setVolume(Math.pow(value, 1.660964));
-  }
-
-  /**
-   * The current volume of the broadcast
-   * @readonly
-   * @type {number}
-   */
-  get volume() {
-    return this._volume;
-  }
-
   get _playableStream() {
-    if (!this.currentTranscoder) return null;
-    return this.currentTranscoder.transcoder.output || this.currentTranscoder.options.stream;
+    const currentTranscoder = this.currentTranscoder;
+    if (!currentTranscoder) return null;
+    const transcoder = currentTranscoder.transcoder;
+    const options = currentTranscoder.options;
+    return (transcoder && transcoder.output) || options.stream;
   }
 
   unregisterDispatcher(dispatcher, old) {
@@ -115,6 +72,7 @@ class VoiceBroadcast extends EventEmitter {
       container.delete(dispatcher);
 
       if (!container.size) {
+        this._encoders.get(volume).destroy();
         this._dispatchers.delete(volume);
         this._encoders.delete(volume);
       }
@@ -175,8 +133,7 @@ class VoiceBroadcast extends EventEmitter {
    *  .catch(console.error);
    */
   playStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
-    options.stream = stream;
+    const options = { seek, volume, passes, stream };
     return this._playTranscodable(stream, options);
   }
 
@@ -202,6 +159,8 @@ class VoiceBroadcast extends EventEmitter {
   }
 
   _playTranscodable(media, options) {
+    OpusEncoders.guaranteeOpusEngine();
+
     this.killCurrentTranscoder();
     const transcoder = this.prism.transcode({
       type: 'ffmpeg',
@@ -242,6 +201,8 @@ class VoiceBroadcast extends EventEmitter {
    * @returns {VoiceBroadcast}
    */
   playConvertedStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    OpusEncoders.guaranteeOpusEngine();
+
     this.killCurrentTranscoder();
     const options = { seek, volume, passes, stream };
     this.currentTranscoder = { options };
@@ -249,6 +210,20 @@ class VoiceBroadcast extends EventEmitter {
     return this;
   }
 
+  /**
+   * Plays an Opus encoded stream at 48KHz.
+   * <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 };
+    stream.once('readable', () => this._startPlaying());
+    return this;
+  }
+
   /**
    * Play an arbitrary input that can be [handled by ffmpeg](https://ffmpeg.org/ffmpeg-protocols.html#Description)
    * @param {string} input the arbitrary input
@@ -256,8 +231,10 @@ class VoiceBroadcast extends EventEmitter {
    * @returns {VoiceBroadcast}
    */
   playArbitraryInput(input, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
-    return this.player.playUnknownStream(input, options);
+    this.guaranteeOpusEngine();
+
+    const options = { seek, volume, passes, input };
+    return this._playTranscodable(input, options);
   }
 
   /**
@@ -284,6 +261,10 @@ class VoiceBroadcast extends EventEmitter {
     }
   }
 
+  guaranteeOpusEngine() {
+    if (!this.opusEncoder) throw new Error('Couldn\'t find an Opus engine.');
+  }
+
   _startPlaying() {
     if (this.tickInterval) clearInterval(this.tickInterval);
     // this.tickInterval = this.client.setInterval(this.tick.bind(this), 20);
@@ -301,9 +282,9 @@ class VoiceBroadcast extends EventEmitter {
       setTimeout(() => this.tick(), 20);
       return;
     }
-    const stream = this._playableStream;
-    const bufferLength = 1920 * 2;
-    let buffer = stream.read(bufferLength);
+
+    const opus = this.currentTranscoder.opus;
+    const buffer = this.readStreamBuffer();
 
     if (!buffer) {
       this._missed++;
@@ -318,12 +299,6 @@ class VoiceBroadcast extends EventEmitter {
 
     this._missed = 0;
 
-    if (buffer.length !== bufferLength) {
-      const newBuffer = Buffer.alloc(bufferLength).fill(0);
-      buffer.copy(newBuffer);
-      buffer = newBuffer;
-    }
-
     let packetMatrix = {};
 
     const getOpusPacket = (volume) => {
@@ -336,10 +311,13 @@ class VoiceBroadcast extends EventEmitter {
     };
 
     for (const dispatcher of this.dispatchers) {
+      if (opus) {
+        dispatcher.processPacket(buffer);
+        continue;
+      }
+
       const volume = dispatcher.volume;
-      setImmediate(() => {
-        dispatcher.process(buffer, true, getOpusPacket(volume));
-      });
+      dispatcher.processPacket(getOpusPacket(volume));
     }
 
     const next = 20 + (this._startTime + this._pausedTime + (this._count * 20) - Date.now());
@@ -347,6 +325,22 @@ class VoiceBroadcast extends EventEmitter {
     setTimeout(() => this.tick(), next);
   }
 
+  readStreamBuffer() {
+    const opus = this.currentTranscoder.opus;
+    const bufferLength = (opus ? 80 : 1920) * 2;
+    let buffer = this._playableStream.read(bufferLength);
+    if (opus) return buffer;
+    if (!buffer) return null;
+
+    if (buffer.length !== bufferLength) {
+      const newBuffer = Buffer.alloc(bufferLength).fill(0);
+      buffer.copy(newBuffer);
+      buffer = newBuffer;
+    }
+
+    return buffer;
+  }
+
   /**
    * Stop the current stream from playing without unsubscribing dispatchers.
    */

src/client/voice/VoiceConnection.js

@@ -142,6 +142,7 @@ class VoiceConnection extends EventEmitter {
         self_deaf: false,
       },
     });
+    this.player.destroy();
     /**
      * Emitted when the voice connection disconnects
      * @event VoiceConnection#disconnect
@@ -236,8 +237,7 @@ class VoiceConnection extends EventEmitter {
    *  })
    *  .catch(console.error);
    */
-  playFile(file, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
+  playFile(file, options) {
     return this.player.playUnknownStream(`file:${file}`, options);
   }
 
@@ -247,8 +247,7 @@ class VoiceConnection extends EventEmitter {
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {StreamDispatcher}
    */
-  playArbitraryInput(input, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
+  playArbitraryInput(input, options) {
     return this.player.playUnknownStream(input, options);
   }
 
@@ -268,22 +267,31 @@ class VoiceConnection extends EventEmitter {
    *  })
    *  .catch(console.error);
    */
-  playStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
+  playStream(stream, options) {
     return this.player.playUnknownStream(stream, options);
   }
 
   /**
    * Plays a stream of 16-bit signed stereo PCM at 48KHz.
-   * @param {ReadableStream} stream The audio stream to play.
+   * @param {ReadableStream} stream The audio stream to play
    * @param {StreamOptions} [options] Options for playing the stream
    * @returns {StreamDispatcher}
    */
-  playConvertedStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
-    const options = { seek, volume, passes };
+  playConvertedStream(stream, options) {
     return this.player.playPCMStream(stream, options);
   }
 
+  /**
+   * Plays an Opus encoded stream at 48KHz.
+   * <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, options) {
+    return this.player.playOpusStream(stream, options);
+  }
+
   /**
    * Plays a voice broadcast
    * @param {VoiceBroadcast} broadcast the broadcast to play

src/client/voice/dispatcher/StreamDispatcher.js

@@ -1,4 +1,4 @@
-const EventEmitter = require('events').EventEmitter;
+const VolumeInterface = require('../util/VolumeInterface');
 const NaCl = require('tweetnacl');
 const VoiceBroadcast = require('../VoiceBroadcast');
 
@@ -16,9 +16,9 @@ nonce.fill(0);
  * ```
  * @extends {EventEmitter}
  */
-class StreamDispatcher extends EventEmitter {
+class StreamDispatcher extends VolumeInterface {
   constructor(player, stream, streamOptions) {
-    super();
+    super(streamOptions);
     /**
      * The Audio Player that controls this dispatcher
      * @type {AudioPlayer}
@@ -31,7 +31,6 @@ class StreamDispatcher extends EventEmitter {
     this.stream = stream;
     if (!(this.stream instanceof VoiceBroadcast)) this.startStreaming();
     this.streamOptions = streamOptions;
-    this.streamOptions.volume = this.streamOptions.volume || 0;
 
     const data = this.streamingData;
     data.length = 20;
@@ -48,7 +47,7 @@ class StreamDispatcher extends EventEmitter {
      */
     this.destroyed = false;
 
-    this.setVolume(streamOptions.volume || 1);
+    this._opus = streamOptions.opus;
   }
 
   /**
@@ -86,46 +85,6 @@ class StreamDispatcher extends EventEmitter {
     return this.time + this.streamingData.pausedTime;
   }
 
-  /**
-   * The volume of the stream, relative to the stream's input volume
-   * @type {number}
-   * @readonly
-   */
-  get volume() {
-    return this.streamOptions.volume;
-  }
-
-  /**
-   * Sets the volume relative to the input stream - i.e. 1 is normal, 0.5 is half, 2 is double.
-   * @param {number} volume The volume that you want to set
-   */
-  setVolume(volume) {
-    /**
-     * Emitted when the volume of this dispatcher changes
-     * @param {number} oldVolume the old volume
-     * @param {number} newVolume the new volume
-     * @event StreamDispatcher#volumeChange
-     */
-    this.emit('volumeChange', this.streamOptions.volume, volume);
-    this.streamOptions.volume = volume;
-  }
-
-  /**
-   * Set the volume in decibels
-   * @param {number} db The decibels
-   */
-  setVolumeDecibels(db) {
-    this.setVolume(Math.pow(10, db / 20));
-  }
-
-  /**
-   * Set the volume so that a perceived value of 0.5 is half the perceived volume etc.
-   * @param {number} value The value for the volume
-   */
-  setVolumeLogarithmic(value) {
-    this.setVolume(Math.pow(value, 1.660964));
-  }
-
   /**
    * Stops sending voice packets to the voice connection (stream may still progress however)
    */
@@ -196,20 +155,7 @@ class StreamDispatcher extends EventEmitter {
     return packetBuffer;
   }
 
-  applyVolume(buffer) {
-    if (this.volume === 1) return buffer;
-
-    const out = Buffer.alloc(buffer.length);
-    for (let i = 0; i < buffer.length; i += 2) {
-      if (i >= buffer.length - 1) break;
-      const uint = Math.min(32767, Math.max(-32767, Math.floor(this.volume * buffer.readInt16LE(i))));
-      out.writeInt16LE(uint, i);
-    }
-
-    return out;
-  }
-
-  process(buffer, controlled, packet) {
+  processPacket(packet) {
     try {
       if (this.destroyed) {
         this.setSpeaking(false);
@@ -218,7 +164,38 @@ class StreamDispatcher extends EventEmitter {
 
       const data = this.streamingData;
 
-      if (data.missed >= 5 && !controlled) {
+      if (this.paused) {
+        this.setSpeaking(false);
+        data.pausedTime = data.length * 10;
+        return;
+      }
+
+      if (!packet) {
+        data.missed++;
+        data.pausedTime += data.length * 10;
+        return;
+      }
+
+      this.started();
+      this.missed = 0;
+
+      this.stepStreamingData();
+      this.sendBuffer(null, data.sequence, data.timestamp, packet);
+    } catch (e) {
+      this.destroy('error', e);
+    }
+  }
+
+  process() {
+    try {
+      if (this.destroyed) {
+        this.setSpeaking(false);
+        return;
+      }
+
+      const data = this.streamingData;
+
+      if (data.missed >= 5) {
         this.destroy('end', 'Stream is not generating quickly enough.');
         return;
       }
@@ -227,61 +204,30 @@ class StreamDispatcher extends EventEmitter {
         this.setSpeaking(false);
         // data.timestamp = data.timestamp + 4294967295 ? data.timestamp + 960 : 0;
         data.pausedTime += data.length * 10;
-        // if buffer is provided we are assuming a master process is controlling the dispatcher
-        if (!buffer) this.player.voiceConnection.voiceManager.client.setTimeout(() => this.process(), data.length * 10);
+        this.player.voiceConnection.voiceManager.client.setTimeout(() => this.process(), data.length * 10);
         return;
       }
 
-      if (!buffer && controlled) {
+      this.started();
+
+      const buffer = this.readStreamBuffer();
+      if (!buffer) {
         data.missed++;
         data.pausedTime += data.length * 10;
+        this.player.voiceConnection.voiceManager.client.setTimeout(() => this.process(), data.length * 10);
         return;
       }
 
-      if (!data.startTime) {
-        /**
-         * Emitted once the dispatcher starts streaming
-         * @event StreamDispatcher#start
-         */
-        this.emit('start');
-        data.startTime = Date.now();
-      }
-
-      if (packet) {
-        data.count++;
-        data.sequence = data.sequence < 65535 ? data.sequence + 1 : 0;
-        data.timestamp = data.timestamp + 4294967295 ? data.timestamp + 960 : 0;
-        this.sendBuffer(null, data.sequence, data.timestamp, packet);
-        return;
-      }
-
-      const bufferLength = 1920 * data.channels;
-      if (!controlled) {
-        buffer = this.stream.read(bufferLength);
-        if (!buffer) {
-          data.missed++;
-          data.pausedTime += data.length * 10;
-          this.player.voiceConnection.voiceManager.client.setTimeout(() => this.process(), data.length * 10);
-          return;
-        }
-      }
-
       data.missed = 0;
 
-      if (buffer.length !== bufferLength) {
-        const newBuffer = Buffer.alloc(bufferLength).fill(0);
-        buffer.copy(newBuffer);
-        buffer = newBuffer;
+      this.stepStreamingData();
+
+      if (this._opus) {
+        this.sendBuffer(null, data.sequence, data.timestamp, buffer);
+      } else {
+        this.sendBuffer(buffer, data.sequence, data.timestamp);
       }
 
-      buffer = this.applyVolume(buffer);
-
-      data.count++;
-      data.sequence = data.sequence < 65535 ? data.sequence + 1 : 0;
-      data.timestamp = data.timestamp + 4294967295 ? data.timestamp + 960 : 0;
-      this.sendBuffer(buffer, data.sequence, data.timestamp);
-
-      if (controlled) return;
       const nextTime = data.length + (data.startTime + data.pausedTime + (data.count * data.length) - Date.now());
       this.player.voiceConnection.voiceManager.client.setTimeout(() => this.process(), nextTime);
     } catch (e) {
@@ -289,6 +235,43 @@ class StreamDispatcher extends EventEmitter {
     }
   }
 
+  readStreamBuffer() {
+    const data = this.streamingData;
+    const bufferLength = (this._opus ? 80 : 1920) * data.channels;
+    let buffer = this.stream.read(bufferLength);
+    if (this._opus) return buffer;
+    if (!buffer) return null;
+
+    if (buffer.length !== bufferLength) {
+      const newBuffer = Buffer.alloc(bufferLength).fill(0);
+      buffer.copy(newBuffer);
+      buffer = newBuffer;
+    }
+
+    buffer = this.applyVolume(buffer);
+    return buffer;
+  }
+
+  started() {
+    const data = this.streamingData;
+
+    if (!data.startTime) {
+      /**
+       * Emitted once the dispatcher starts streaming
+       * @event StreamDispatcher#start
+       */
+      this.emit('start');
+      data.startTime = Date.now();
+    }
+  }
+
+  stepStreamingData() {
+    const data = this.streamingData;
+    data.count++;
+    data.sequence = data.sequence < 65535 ? data.sequence + 1 : 0;
+    data.timestamp = data.timestamp + 4294967295 ? data.timestamp + 960 : 0;
+  }
+
   destroy(type, reason) {
     if (this.destroyed) return;
     this.destroyed = true;

src/client/voice/opus/BaseOpusEngine.js

@@ -10,6 +10,10 @@ class BaseOpus {
   decode(buffer) {
     return buffer;
   }
+
+  destroy() {
+    return;
+  }
 }
 
 module.exports = BaseOpus;

src/client/voice/opus/OpusEngineList.js

@@ -20,5 +20,9 @@ exports.fetch = () => {
     const fetched = fetch(encoder);
     if (fetched) return fetched;
   }
-  throw new Error('Couldn\'t find an Opus engine.');
+  return null;
+};
+
+exports.guaranteeOpusEngine = () => {
+  if (!this.opusEncoder) throw new Error('Couldn\'t find an Opus engine.');
 };

src/client/voice/opus/OpusScriptEngine.js

@@ -2,7 +2,7 @@ const OpusEngine = require('./BaseOpusEngine');
 
 let OpusScript;
 
-class NodeOpusEngine extends OpusEngine {
+class OpusScriptEngine extends OpusEngine {
   constructor(player) {
     super(player);
     try {
@@ -22,6 +22,11 @@ class NodeOpusEngine extends OpusEngine {
     super.decode(buffer);
     return this.encoder.decode(buffer);
   }
+
+  destroy() {
+    super.destroy();
+    this.encoder.delete();
+  }
 }
 
-module.exports = NodeOpusEngine;
+module.exports = OpusScriptEngine;

src/client/voice/player/AudioPlayer.js

@@ -50,6 +50,10 @@ class AudioPlayer extends EventEmitter {
     return this.streams.last().transcoder;
   }
 
+  destroy() {
+    this.opusEncoder.destroy();
+  }
+
   destroyStream(stream) {
     const data = this.streams.get(stream);
     if (!data) return;
@@ -69,6 +73,7 @@ class AudioPlayer extends EventEmitter {
   }
 
   playUnknownStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    OpusEncoders.guaranteeOpusEngine();
     const options = { seek, volume, passes };
     const transcoder = this.prism.transcode({
       type: 'ffmpeg',
@@ -85,28 +90,39 @@ class AudioPlayer extends EventEmitter {
   }
 
   playPCMStream(stream, { seek = 0, volume = 1, passes = 1 } = {}) {
+    OpusEncoders.guaranteeOpusEngine();
     const options = { seek, volume, passes };
     this.destroyAllStreams(stream);
-    const dispatcher = new StreamDispatcher(this, stream, options);
-    dispatcher.on('speaking', value => this.voiceConnection.setSpeaking(value));
+    const dispatcher = this.createDispatcher(stream, options);
     if (!this.streams.has(stream)) this.streams.set(stream, { dispatcher, input: stream });
     this.streams.get(stream).dispatcher = dispatcher;
-    dispatcher.on('end', () => this.destroyStream(stream));
-    dispatcher.on('error', () => this.destroyStream(stream));
+    return dispatcher;
+  }
+
+  playOpusStream(stream, { seek = 0, passes = 1 } = {}) {
+    const options = { seek, passes, opus: true };
+    this.destroyAllStreams(stream);
+    const dispatcher = this.createDispatcher(stream, options);
+    this.streams.set(stream, { dispatcher, input: stream });
     return dispatcher;
   }
 
   playBroadcast(broadcast, { volume = 1, passes = 1 } = {}) {
     const options = { volume, passes };
     this.destroyAllStreams();
-    const dispatcher = new StreamDispatcher(this, broadcast, options);
-    dispatcher.on('end', () => this.destroyStream(broadcast));
-    dispatcher.on('error', () => this.destroyStream(broadcast));
-    dispatcher.on('speaking', value => this.voiceConnection.setSpeaking(value));
+    const dispatcher = this.createDispatcher(broadcast, options);
     this.streams.set(broadcast, { dispatcher, input: broadcast });
     broadcast.registerDispatcher(dispatcher);
     return dispatcher;
   }
+
+  createDispatcher(stream, options) {
+    const dispatcher = new StreamDispatcher(this, stream, options);
+    dispatcher.on('end', () => this.destroyStream(stream));
+    dispatcher.on('error', () => this.destroyStream(stream));
+    dispatcher.on('speaking', value => this.voiceConnection.setSpeaking(value));
+    return dispatcher;
+  }
 }
 
 module.exports = AudioPlayer;

src/client/voice/receiver/VoiceReceiver.js

@@ -84,7 +84,8 @@ class VoiceReceiver extends EventEmitter {
       stream._push(null);
       this.opusStreams.delete(id);
     }
-    for (const [id] of this.opusEncoders) {
+    for (const [id, encoder] of this.opusEncoders) {
+      encoder.destroy();
       this.opusEncoders.delete(id);
     }
     this.destroyed = true;

src/client/voice/util/VolumeInterface.js

@@ -0,0 +1,57 @@
+const EventEmitter = require('events');
+
+class VolumeInterface extends EventEmitter {
+  constructor({ volume = 0 } = {}) {
+    super();
+    this.setVolume(volume || 1);
+  }
+
+  applyVolume(buffer, volume) {
+    volume = volume || this._volume;
+    if (volume === 1) return buffer;
+
+    const out = new Buffer(buffer.length);
+    for (let i = 0; i < buffer.length; i += 2) {
+      if (i >= buffer.length - 1) break;
+      const uint = Math.min(32767, Math.max(-32767, Math.floor(volume * buffer.readInt16LE(i))));
+      out.writeInt16LE(uint, i);
+    }
+
+    return out;
+  }
+
+  /**
+   * Sets the volume relative to the input stream - i.e. 1 is normal, 0.5 is half, 2 is double.
+   * @param {number} volume The volume that you want to set
+   */
+  setVolume(volume) {
+    this._volume = volume;
+  }
+
+  /**
+   * Set the volume in decibels
+   * @param {number} db The decibels
+   */
+  setVolumeDecibels(db) {
+    this.setVolume(Math.pow(10, db / 20));
+  }
+
+  /**
+   * Set the volume so that a perceived value of 0.5 is half the perceived volume etc.
+   * @param {number} value The value for the volume
+   */
+  setVolumeLogarithmic(value) {
+    this.setVolume(Math.pow(value, 1.660964));
+  }
+
+  /**
+   * The current volume of the broadcast
+   * @readonly
+   * @type {number}
+   */
+  get volume() {
+    return this._volume;
+  }
+}
+
+module.exports = VolumeInterface;