506 lines
16 KiB
JavaScript
506 lines
16 KiB
JavaScript
// this controls if the new AudioWorklet API should be used if available.
|
|
// the engine will still fall back to the ScriptProcessorNode if this is set to true but not available in the browser.
|
|
var useAudioWorklets = true;
|
|
|
|
function AudioEngine(maxBufferLength, audioReporter) {
|
|
this.audioReporter = audioReporter;
|
|
this.initStats();
|
|
this.resetStats();
|
|
|
|
this.onStartCallbacks = [];
|
|
|
|
this.started = false;
|
|
this.audioContext = this.buildAudioContext();
|
|
if (!this.audioContext) {
|
|
return;
|
|
}
|
|
|
|
var me = this;
|
|
this.audioContext.onstatechange = function() {
|
|
if (me.audioContext.state !== 'running') return;
|
|
me._start();
|
|
}
|
|
|
|
this.audioCodecs = {
|
|
"adpcm": new ImaAdpcmCodec(),
|
|
"opus": new OpusCodec(this.audioContext)
|
|
};
|
|
|
|
this.compression = 'none';
|
|
|
|
this.setupResampling();
|
|
this.resampler = new Interpolator(this.resamplingFactor);
|
|
this.hdResampler = new Interpolator(this.hdResamplingFactor);
|
|
|
|
this.maxBufferSize = maxBufferLength * this.getSampleRate();
|
|
}
|
|
|
|
AudioEngine.prototype.buildAudioContext = function() {
|
|
var ctxClass = window.AudioContext || window.webkitAudioContext;
|
|
if (!ctxClass) {
|
|
return;
|
|
}
|
|
|
|
// known good sample rates
|
|
var goodRates = [48000, 44100, 96000]
|
|
|
|
// let the browser chose the sample rate, if it is good, use it
|
|
var ctx = new ctxClass({latencyHint: 'playback'});
|
|
if (goodRates.indexOf(ctx.sampleRate) >= 0) {
|
|
return ctx;
|
|
}
|
|
|
|
// if that didn't work, try if any of the good rates work
|
|
if (goodRates.some(function(sr) {
|
|
try {
|
|
ctx = new ctxClass({sampleRate: sr, latencyHint: 'playback'});
|
|
return true;
|
|
} catch (e) {
|
|
return false;
|
|
}
|
|
}, this)) {
|
|
return ctx;
|
|
}
|
|
|
|
// fallback: let the browser decide
|
|
// this may cause playback problems down the line
|
|
return new ctxClass({latencyHint: 'playback'});
|
|
}
|
|
|
|
AudioEngine.prototype.resume = function(){
|
|
this.audioContext.resume();
|
|
}
|
|
|
|
AudioEngine.prototype._start = function() {
|
|
var me = this;
|
|
|
|
// if failed to find a valid resampling factor...
|
|
if (me.resamplingFactor === 0) {
|
|
return;
|
|
}
|
|
|
|
// been started before?
|
|
if (me.started) {
|
|
return;
|
|
}
|
|
|
|
// are we allowed to play audio?
|
|
if (!me.isAllowed()) {
|
|
return;
|
|
}
|
|
me.started = true;
|
|
|
|
var runCallbacks = function(workletType) {
|
|
var callbacks = me.onStartCallbacks;
|
|
me.onStartCallbacks = false;
|
|
callbacks.forEach(function(c) { c(workletType); });
|
|
};
|
|
|
|
me.gainNode = me.audioContext.createGain();
|
|
me.gainNode.connect(me.audioContext.destination);
|
|
|
|
if (useAudioWorklets && me.audioContext.audioWorklet) {
|
|
me.audioContext.audioWorklet.addModule('static/lib/AudioProcessor.js').then(function(){
|
|
me.audioNode = new AudioWorkletNode(me.audioContext, 'openwebrx-audio-processor', {
|
|
numberOfInputs: 0,
|
|
numberOfOutputs: 1,
|
|
outputChannelCount: [1],
|
|
processorOptions: {
|
|
maxBufferSize: me.maxBufferSize
|
|
}
|
|
});
|
|
me.audioNode.connect(me.gainNode);
|
|
me.audioNode.port.addEventListener('message', function(m){
|
|
var json = JSON.parse(m.data);
|
|
if (typeof(json.buffersize) !== 'undefined') {
|
|
me.audioReporter({
|
|
buffersize: json.buffersize
|
|
});
|
|
}
|
|
if (typeof(json.samplesProcessed) !== 'undefined') {
|
|
me.audioSamples.add(json.samplesProcessed);
|
|
}
|
|
});
|
|
me.audioNode.port.start();
|
|
runCallbacks('AudioWorklet');
|
|
});
|
|
} else {
|
|
me.audioBuffers = [];
|
|
|
|
if (!AudioBuffer.prototype.copyToChannel) { //Chrome 36 does not have it, Firefox does
|
|
AudioBuffer.prototype.copyToChannel = function (input, channel) //input is Float32Array
|
|
{
|
|
var cd = this.getChannelData(channel);
|
|
for (var i = 0; i < input.length; i++) cd[i] = input[i];
|
|
}
|
|
}
|
|
|
|
var bufferSize;
|
|
if (me.audioContext.sampleRate < 44100 * 2)
|
|
bufferSize = 4096;
|
|
else if (me.audioContext.sampleRate >= 44100 * 2 && me.audioContext.sampleRate < 44100 * 4)
|
|
bufferSize = 4096 * 2;
|
|
else if (me.audioContext.sampleRate > 44100 * 4)
|
|
bufferSize = 4096 * 4;
|
|
|
|
|
|
function audio_onprocess(e) {
|
|
var total = 0;
|
|
var out = new Float32Array(bufferSize);
|
|
while (me.audioBuffers.length) {
|
|
var b = me.audioBuffers.shift();
|
|
// not enough space to fit all data, so splice and put back in the queue
|
|
if (total + b.length > bufferSize) {
|
|
var spaceLeft = bufferSize - total;
|
|
var tokeep = b.subarray(0, spaceLeft);
|
|
out.set(tokeep, total);
|
|
var tobuffer = b.subarray(spaceLeft, b.length);
|
|
me.audioBuffers.unshift(tobuffer);
|
|
total += spaceLeft;
|
|
break;
|
|
} else {
|
|
out.set(b, total);
|
|
total += b.length;
|
|
}
|
|
}
|
|
|
|
e.outputBuffer.copyToChannel(out, 0);
|
|
me.audioSamples.add(total);
|
|
|
|
}
|
|
|
|
//on Chrome v36, createJavaScriptNode has been replaced by createScriptProcessor
|
|
var method = 'createScriptProcessor';
|
|
if (me.audioContext.createJavaScriptNode) {
|
|
method = 'createJavaScriptNode';
|
|
}
|
|
me.audioNode = me.audioContext[method](bufferSize, 0, 1);
|
|
me.audioNode.onaudioprocess = audio_onprocess;
|
|
me.audioNode.connect(me.gainNode);
|
|
runCallbacks('ScriptProcessorNode')
|
|
}
|
|
|
|
setInterval(me.reportStats.bind(me), 1000);
|
|
};
|
|
|
|
AudioEngine.prototype.onStart = function(callback) {
|
|
if (this.onStartCallbacks) {
|
|
this.onStartCallbacks.push(callback);
|
|
} else {
|
|
callback();
|
|
}
|
|
};
|
|
|
|
AudioEngine.prototype.isAllowed = function() {
|
|
return this.audioContext.state === 'running';
|
|
};
|
|
|
|
AudioEngine.prototype.reportStats = function() {
|
|
if (this.audioNode.port) {
|
|
this.audioNode.port.postMessage(JSON.stringify({cmd:'getStats'}));
|
|
} else {
|
|
this.audioReporter({
|
|
buffersize: this.getBuffersize()
|
|
});
|
|
}
|
|
};
|
|
|
|
AudioEngine.prototype.initStats = function() {
|
|
var me = this;
|
|
var buildReporter = function(key) {
|
|
return function(v){
|
|
var report = {};
|
|
report[key] = v;
|
|
me.audioReporter(report);
|
|
}
|
|
|
|
};
|
|
|
|
this.audioBytes = new Measurement();
|
|
this.audioBytes.report(10000, 1000, buildReporter('audioByteRate'));
|
|
|
|
this.audioSamples = new Measurement();
|
|
this.audioSamples.report(10000, 1000, buildReporter('audioRate'));
|
|
};
|
|
|
|
AudioEngine.prototype.resetStats = function() {
|
|
this.audioBytes.reset();
|
|
this.audioSamples.reset();
|
|
};
|
|
|
|
AudioEngine.prototype.setupResampling = function() { //both at the server and the client
|
|
var targetRate = this.audioContext.sampleRate;
|
|
var audio_params = this.findRate(8000, 12000);
|
|
if (!audio_params) {
|
|
this.resamplingFactor = 0;
|
|
this.outputRate = 0;
|
|
divlog('Your audio card sampling rate (' + targetRate + ') is not supported.<br />Please change your operating system default settings in order to fix this.', 1);
|
|
} else {
|
|
this.resamplingFactor = audio_params.resamplingFactor;
|
|
this.outputRate = audio_params.outputRate;
|
|
}
|
|
|
|
var hd_audio_params = this.findRate(36000, 48000);
|
|
if (!hd_audio_params) {
|
|
this.hdResamplingFactor = 0;
|
|
this.hdOutputRate = 0;
|
|
divlog('Your audio card sampling rate (' + targetRate + ') is not supported for HD audio<br />Please change your operating system default settings in order to fix this.', 1);
|
|
} else {
|
|
this.hdResamplingFactor = hd_audio_params.resamplingFactor;
|
|
this.hdOutputRate = hd_audio_params.outputRate;
|
|
}
|
|
};
|
|
|
|
AudioEngine.prototype.findRate = function(low, high) {
|
|
var targetRate = this.audioContext.sampleRate;
|
|
var i = 1;
|
|
while (true) {
|
|
var audio_server_output_rate = Math.floor(targetRate / i);
|
|
if (audio_server_output_rate < low) {
|
|
return;
|
|
} else if (audio_server_output_rate >= low && audio_server_output_rate <= high) {
|
|
return {
|
|
resamplingFactor: i,
|
|
outputRate: audio_server_output_rate
|
|
}
|
|
}
|
|
i++;
|
|
};
|
|
}
|
|
|
|
AudioEngine.prototype.getOutputRate = function() {
|
|
return this.outputRate;
|
|
};
|
|
|
|
AudioEngine.prototype.getHdOutputRate = function() {
|
|
return this.hdOutputRate;
|
|
}
|
|
|
|
AudioEngine.prototype.getSampleRate = function() {
|
|
return this.audioContext.sampleRate;
|
|
};
|
|
|
|
AudioEngine.prototype.processAudio = function(data, resampler) {
|
|
var me = this;
|
|
|
|
if (!this.audioNode) return;
|
|
this.audioBytes.add(data.byteLength);
|
|
|
|
var audioDataCallback = function(buffer) {
|
|
buffer = resampler.process(buffer);
|
|
if (me.audioNode.port) {
|
|
// AudioWorklets supported
|
|
me.audioNode.port.postMessage(buffer);
|
|
} else {
|
|
// silently drop excess samples
|
|
if (this.getBuffersize() + buffer.length <= this.maxBufferSize) {
|
|
this.audioBuffers.push(buffer);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (this.compression !== "none") {
|
|
//resampling & ADPCM
|
|
this.audioCodecs[this.compression].decodeAsync(new Uint8Array(data), audioDataCallback);
|
|
} else {
|
|
audioDataCallback(new Int16Array(data))
|
|
}
|
|
|
|
}
|
|
|
|
AudioEngine.prototype.pushAudio = function(data) {
|
|
this.processAudio(data, this.resampler);
|
|
};
|
|
|
|
AudioEngine.prototype.pushHdAudio = function(data) {
|
|
this.processAudio(data, this.hdResampler);
|
|
}
|
|
|
|
AudioEngine.prototype.setCompression = function(compression) {
|
|
this.compression = compression;
|
|
};
|
|
|
|
AudioEngine.prototype.setVolume = function(volume) {
|
|
this.gainNode.gain.value = volume;
|
|
};
|
|
|
|
AudioEngine.prototype.getBuffersize = function() {
|
|
// only available when using ScriptProcessorNode
|
|
if (!this.audioBuffers) return 0;
|
|
return this.audioBuffers.map(function(b){ return b.length; }).reduce(function(a, b){ return a + b; }, 0);
|
|
};
|
|
|
|
function ImaAdpcmCodec() {
|
|
this.reset();
|
|
}
|
|
|
|
ImaAdpcmCodec.prototype.reset = function() {
|
|
this.stepIndex = 0;
|
|
this.predictor = 0;
|
|
this.step = 0;
|
|
this.synchronized = 0;
|
|
this.syncWord = "SYNC";
|
|
this.syncCounter = 0;
|
|
this.skip = 0;
|
|
};
|
|
|
|
ImaAdpcmCodec.imaIndexTable = [ -1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8 ];
|
|
|
|
ImaAdpcmCodec.imaStepTable = [
|
|
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
|
|
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
|
|
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
|
|
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
|
|
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
|
|
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
|
|
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
|
|
5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
|
|
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
|
|
];
|
|
|
|
ImaAdpcmCodec.prototype.decode = function(data) {
|
|
var output = new Int16Array(data.length * 2);
|
|
for (var i = 0; i < data.length; i++) {
|
|
output[i * 2] = this.decodeNibble(data[i] & 0x0F);
|
|
output[i * 2 + 1] = this.decodeNibble((data[i] >> 4) & 0x0F);
|
|
}
|
|
return output;
|
|
};
|
|
|
|
ImaAdpcmCodec.prototype.decodeAsync = function(data, callback) {
|
|
var output = new Int16Array(data.length * 2);
|
|
var index = this.skip;
|
|
var oi = 0;
|
|
while (index < data.length) {
|
|
while (this.synchronized < 4 && index < data.length) {
|
|
if (data[index] === this.syncWord.charCodeAt(this.synchronized)) {
|
|
this.synchronized++;
|
|
} else {
|
|
this.synchronized = 0;
|
|
}
|
|
index++;
|
|
if (this.synchronized === 4) {
|
|
if (index + 4 < data.length) {
|
|
var syncData = new Int16Array(data.buffer.slice(index, index + 4));
|
|
this.stepIndex = syncData[0];
|
|
this.predictor = syncData[1];
|
|
}
|
|
this.syncCounter = 1000;
|
|
index += 4;
|
|
break;
|
|
}
|
|
}
|
|
while (index < data.length) {
|
|
if (this.syncCounter-- < 0) {
|
|
this.synchronized = 0;
|
|
break;
|
|
}
|
|
output[oi++] = this.decodeNibble(data[index] & 0x0F);
|
|
output[oi++] = this.decodeNibble(data[index] >> 4);
|
|
index++;
|
|
}
|
|
}
|
|
this.skip = index - data.length;
|
|
callback(output.slice(0, oi));
|
|
};
|
|
|
|
ImaAdpcmCodec.prototype.decodeNibble = function(nibble) {
|
|
this.stepIndex += ImaAdpcmCodec.imaIndexTable[nibble];
|
|
this.stepIndex = Math.min(Math.max(this.stepIndex, 0), 88);
|
|
|
|
var diff = this.step >> 3;
|
|
if (nibble & 1) diff += this.step >> 2;
|
|
if (nibble & 2) diff += this.step >> 1;
|
|
if (nibble & 4) diff += this.step;
|
|
if (nibble & 8) diff = -diff;
|
|
|
|
this.predictor += diff;
|
|
this.predictor = Math.min(Math.max(this.predictor, -32768), 32767);
|
|
|
|
this.step = ImaAdpcmCodec.imaStepTable[this.stepIndex];
|
|
|
|
return this.predictor;
|
|
};
|
|
|
|
function OpusCodec(context) {
|
|
this.context = context;
|
|
}
|
|
|
|
OpusCodec.prototype.decodeAsync = function(data, callback) {
|
|
this.context.decodeAudioData(new ArrayBuffer(data)).then(callback);
|
|
};
|
|
|
|
function Interpolator(factor) {
|
|
this.factor = factor;
|
|
this.lowpass = new Lowpass(factor)
|
|
}
|
|
|
|
Interpolator.prototype.process = function(data) {
|
|
var output = new Float32Array(data.length * this.factor);
|
|
for (var i = 0; i < data.length; i++) {
|
|
output[i * this.factor] = (data[i] + 0.5) / 32768;
|
|
}
|
|
return this.lowpass.process(output);
|
|
};
|
|
|
|
function Lowpass(interpolation) {
|
|
this.interpolation = interpolation;
|
|
var transitionBandwidth = 0.05;
|
|
this.numtaps = Math.round(4 / transitionBandwidth);
|
|
if (this.numtaps % 2 == 0) this.numtaps += 1;
|
|
|
|
var cutoff = 1 / interpolation;
|
|
this.coefficients = this.getCoefficients(cutoff / 2);
|
|
|
|
this.delay = new Float32Array(this.numtaps);
|
|
for (var i = 0; i < this.numtaps; i++){
|
|
this.delay[i] = 0;
|
|
}
|
|
this.delayIndex = 0;
|
|
}
|
|
|
|
Lowpass.prototype.getCoefficients = function(cutoffRate) {
|
|
var middle = Math.floor(this.numtaps / 2);
|
|
// hamming window
|
|
var window_function = function(r){
|
|
var rate = 0.5 + r / 2;
|
|
return 0.54 - 0.46 * Math.cos(2 * Math.PI * rate);
|
|
}
|
|
var output = [];
|
|
output[middle] = 2 * Math.PI * cutoffRate * window_function(0);
|
|
for (var i = 1; i <= middle; i++) {
|
|
output[middle - i] = output[middle + i] = (Math.sin(2 * Math.PI * cutoffRate * i) / i) * window_function(i / middle);
|
|
}
|
|
return this.normalizeCoefficients(output);
|
|
};
|
|
|
|
Lowpass.prototype.normalizeCoefficients = function(input) {
|
|
var sum = 0;
|
|
var output = [];
|
|
for (var i = 0; i < input.length; i++) {
|
|
sum += input[i];
|
|
}
|
|
for (var i = 0; i < input.length; i++) {
|
|
output[i] = input[i] / sum;
|
|
}
|
|
return output;
|
|
};
|
|
|
|
Lowpass.prototype.process = function(input) {
|
|
output = new Float32Array(input.length);
|
|
for (var oi = 0; oi < input.length; oi++) {
|
|
this.delay[this.delayIndex] = input[oi];
|
|
this.delayIndex = (this.delayIndex + 1) % this.numtaps;
|
|
|
|
var acc = 0;
|
|
var index = this.delayIndex;
|
|
for (var i = 0; i < this.numtaps; ++i) {
|
|
var index = index != 0 ? index - 1 : this.numtaps - 1;
|
|
acc += this.delay[index] * this.coefficients[i];
|
|
if (isNaN(acc)) debugger;
|
|
}
|
|
// gain by interpolation
|
|
output[oi] = this.interpolation * acc;
|
|
}
|
|
return output;
|
|
}; |