115 lines
3.3 KiB
JavaScript
115 lines
3.3 KiB
JavaScript
var
|
|
Writable = require('stream').Writable,
|
|
util = require('util')
|
|
;
|
|
|
|
function Input(args) {
|
|
Writable.call(this, args);
|
|
|
|
if (typeof args === 'undefined') args = {};
|
|
if (args.channels != 1 && args.channels != 2) args.channels = 2;
|
|
if (typeof args.sampleRate !== 'number' || args.sampleRate < 1) args.sampleRate = 44100;
|
|
|
|
this.buffer = new Buffer(0);
|
|
|
|
if (args.channels == 1) this.readMono = this.read;
|
|
if (args.channels == 2) this.readStereo = this.read;
|
|
|
|
if (args.bitDepth == 8) {
|
|
this.readSample = this.buffer.readInt8;
|
|
this.writeSample = this.buffer.writeInt8;
|
|
this.sampleByteLength = 1;
|
|
}
|
|
else if (args.bitDepth == 32) {
|
|
this.readSample = this.buffer.readInt32LE;
|
|
this.writeSample = this.buffer.writeInt32LE;
|
|
this.sampleByteLength = 4;
|
|
}
|
|
else {
|
|
args.bitDepth = 16;
|
|
this.readSample = this.buffer.readInt16LE;
|
|
this.writeSample = this.buffer.writeInt16LE;
|
|
this.sampleByteLength = 2;
|
|
}
|
|
|
|
this.channels = args.channels;
|
|
this.bitDepth = args.bitDepth;
|
|
this.sampleRate = args.sampleRate;
|
|
|
|
this.getMoreData = null;
|
|
}
|
|
|
|
util.inherits(Input, Writable);
|
|
|
|
Input.prototype.read = function (samples) {
|
|
console.log('read()');
|
|
var bytes = samples * (this.bitDepth / 8) * this.channels;
|
|
if (this.buffer.length < bytes) bytes = this.buffer.length;
|
|
console.log(this.buffer.length);
|
|
var r = this.buffer.slice(0, bytes);
|
|
this.buffer = this.buffer.slice(bytes);
|
|
console.log(this.buffer.length);
|
|
|
|
if (this.buffer.length <= 131072 && this.getMoreData !== null) {
|
|
var getMoreData = this.getMoreData;
|
|
this.getMoreData = null;
|
|
process.nextTick(getMoreData);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
Input.prototype.readMono = function (samples) {
|
|
console.log('readMono()');
|
|
// This function will be overridden by this.read, if input already is mono.
|
|
var stereoBuffer = this.read(samples);
|
|
var monoBuffer = new Buffer(stereoBuffer.length / 2);
|
|
var s = this.availSamples(stereoBuffer.length);
|
|
for (var i = 0; i < s; i++) {
|
|
var l = this.readSample.call(stereoBuffer, i * this.sampleByteLength * 2);
|
|
var r = this.readSample.call(stereoBuffer, (i * this.sampleByteLength * 2) + this.sampleByteLength);
|
|
this.writeSample.call(monoBuffer, Math.round((l + r) / 2), i * this.sampleByteLength);
|
|
}
|
|
return monoBuffer;
|
|
}
|
|
|
|
Input.prototype.readStereo = function (samples) {
|
|
console.log('readStereo()');
|
|
// This function will be overridden by this.read, if input already is stereo.
|
|
var monoBuffer = this.read(samples);
|
|
var stereoBuffer = new Buffer(monoBuffer.length * 2);
|
|
var s = this.availSamples(monoBuffer.length);
|
|
for (var i = 0; i < s; i++) {
|
|
var m = this.readSample.call(monoBuffer, i * this.sampleByteLength);
|
|
this.writeSample.call(stereoBuffer, m, i * this.sampleByteLength * 2);
|
|
this.writeSample.call(stereoBuffer, m, (i * this.sampleByteLength * 2) + this.sampleByteLength);
|
|
}
|
|
return stereoBuffer;
|
|
}
|
|
|
|
Input.prototype.availSamples = function (length) {
|
|
if (typeof length === 'undefined') length = this.buffer.length;
|
|
return Math.floor(length / ((this.bitDepth / 8) * this.channels));
|
|
}
|
|
|
|
Input.prototype._write = function (chunk, encoding, next) {
|
|
|
|
console.log('_write', arguments);
|
|
|
|
/*
|
|
if (!Buffer.isBuffer(chunk)) {
|
|
chunk = new Buffer(chunk, encoding);
|
|
}
|
|
*/
|
|
this.buffer = Buffer.concat([this.buffer, chunk]);
|
|
if (this.buffer.length > 131072) {
|
|
this.getMoreData = next;
|
|
} else {
|
|
next();
|
|
}
|
|
|
|
|
|
}
|
|
|
|
module.exports = Input;
|