Adding volume wrapper

src/Voice/VolumeTransformer.js

@@ -0,0 +1,45 @@
+const Transform = require('stream').Transform;
+
+class Volume extends Transform {
+	get volume() {
+		return this._volume === undefined ? 1 : this._volume;
+	}
+
+	set volume(value) {
+		this._volume = value;
+	}
+
+	get multiplier() {
+		return Math.tan(this.volume);
+	}
+
+	get() {
+		return this.volume;
+	}
+
+	set(volume) {
+		this.volume = volume;
+	}
+
+	_transform(buffer, encoding, callback) {
+		let out = new Buffer(buffer.length);
+
+		for (let i = 0; i < buffer.length; i += 2) {
+			// Read Int16, multiple with multiplier and round down
+			//console.log(this.volume, this.multiplier, buffer.readInt16LE(i));
+			let uint = Math.floor(this.multiplier * buffer.readInt16LE(i));
+
+			// Ensure value stays within 16bit
+			uint = Math.min(32767, uint);
+			uint = Math.max(-32767, uint);
+
+			// Write 2 new bytes into other buffer;
+			out.writeInt16LE(uint, i);
+		}
+
+		this.push(out);
+		callback();
+	}
+}
+
+module.exports = Volume;