Haha-Yes/node_modules/prism-media/src/transformers/PCMVolume.js
2018-09-09 21:20:36 +02:00

113 lines
3.2 KiB
JavaScript

// Based on discord.js' old volume system
const { Transform } = require('stream');
const loader = require('../util/loader');
const krypton = loader.require([['krypton']]).fn;
class VolumeTransformer extends Transform {
constructor(options = {}) {
super(options);
this._bits = options.bits;
this._bytes = this._bits / 8;
this._extremum = Math.pow(2, this._bits - 1) - 1;
this.volume = options.volume || 1;
this._chunk = Buffer.alloc(0);
}
_readInt(buffer, index) { return index; }
_writeInt(buffer, int, index) { return index; }
_transform(chunk, encoding, done) {
// If the volume is 1, act like a passthrough stream
if (this.volume === 1) {
this.push(chunk);
return done();
}
const { _bytes, _extremum } = this;
chunk = this._chunk = Buffer.concat([this._chunk, chunk]);
if (chunk.length < _bytes) return done();
let transformed;
let complete;
if (krypton && krypton.pcm.simd && this._krypton) {
if (chunk.length < 64) return done();
transformed = this._krypton(chunk.slice(0, chunk.length - (chunk.length % 64)), this.volume);
complete = transformed.length;
} else {
transformed = Buffer.alloc(chunk.length);
complete = Math.floor(chunk.length / _bytes) * _bytes;
for (let i = 0; i < complete; i += _bytes) {
const int = Math.min(_extremum, Math.max(-_extremum, Math.floor(this.volume * this._readInt(chunk, i))));
this._writeInt(transformed, int, i);
}
}
this._chunk = chunk.slice(complete);
this.push(transformed);
return done();
}
_destroy(err, cb) {
super._destroy(err, cb);
this._chunk = null;
}
setVolume(volume) {
this.volume = volume;
}
setVolumeDecibels(db) {
this.setVolume(Math.pow(10, db / 20));
}
setVolumeLogarithmic(value) {
this.setVolume(Math.pow(value, 1.660964));
}
get volumeDecibels() {
return Math.log10(this._volume) * 20;
}
get volumeLogarithmic() {
return Math.pow(this._volume, 1 / 1.660964);
}
}
class VolumeTransformer16LE extends VolumeTransformer {
constructor(options) { super({ ...options, bits: 16 }); }
_readInt(buffer, index) { return buffer.readInt16LE(index); }
_writeInt(buffer, int, index) { return buffer.writeInt16LE(int, index); }
_krypton(buffer, volume) {
return krypton.do(krypton.pcm.volume16(buffer, volume)).run(false);
}
}
class VolumeTransformer16BE extends VolumeTransformer {
constructor(options) { super({ ...options, bits: 16 }); }
_readInt(buffer, index) { return buffer.readInt16BE(index); }
_writeInt(buffer, int, index) { return buffer.writeInt16BE(int, index); }
}
class VolumeTransformer32LE extends VolumeTransformer {
constructor(options) { super({ ...options, bits: 32 }); }
_readInt(buffer, index) { return buffer.readInt32LE(index); }
_writeInt(buffer, int, index) { return buffer.writeInt32LE(int, index); }
}
class VolumeTransformer32BE extends VolumeTransformer {
constructor(options) { super({ ...options, bits: 32 }); }
_readInt(buffer, index) { return buffer.readInt32BE(index); }
_writeInt(buffer, int, index) { return buffer.writeInt32BE(int, index); }
}
module.exports = {
VolumeTransformer16LE,
VolumeTransformer16BE,
VolumeTransformer32LE,
VolumeTransformer32BE,
};