580 lines
19 KiB
JavaScript
580 lines
19 KiB
JavaScript
var audioContext;
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var sendButton;
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var textToSend;
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var isListeningCheckbox;
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var samplesPerBitLabel;
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var microphoneStream;
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var microphoneNode;
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var analyser;
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var receivedDataTextarea;
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var sentDataTextArea;
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var receivedGraph;
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var receivedData = [];
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var MAX_BITS_DISPLAYED_ON_GRAPH = 11;
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var MAX_DATA = 300;
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var pauseTimeoutId;
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var sampleIntervalId;
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// 20 to 20,000 - human
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var FREQUENCY_TONE = 18000;
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var MINIMUM_FREQUENCY = 5000;
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var MAXIMUM_FREQUENCY = 10000;
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var FREQUENCY_DURATION = 100;
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var FREQUENCY_THRESHOLD_PERCENT = .75;
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var FREQUENCY_THRESHOLD = 150;
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var FREQUENCY_RESOLUTION_MULTIPLIER = 2;
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var SAMPLE_DELAY_MS = 1;
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var FFT_POWER = 10;
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var LAST_BIT_PERCENT = 0.8;
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var SMOOTHING_TIME_CONSTANT = 0;
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var frequencyOverTime = [];
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var bitStart = [];
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var samplesPerBit = [];
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var bitSampleCount = 0;
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var PAUSE = false;
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var PAUSE_AFTER_END = true;
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function handleWindowLoad() {
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// grab dom elements
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sendButton = document.getElementById('send-button');
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isListeningCheckbox = document.getElementById('is-listening-checkbox');
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receivedDataTextarea = document.getElementById('received-data');
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receivedGraph = document.getElementById('received-graph');
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textToSend = document.getElementById('text-to-send');
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sentDataTextArea = document.getElementById('sent-data');
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samplesPerBitLabel = document.getElementById('samples-per-bit');
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document.getElementById('pause-after-end').checked = PAUSE_AFTER_END;
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document.getElementById('pause-after-end').addEventListener('change', event => {
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PAUSE_AFTER_END = event.target.checked;
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if(!PAUSE_AFTER_END) resumeGraph();
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})
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document.getElementById('frequency-resolution-multiplier').value = FREQUENCY_RESOLUTION_MULTIPLIER;
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document.getElementById('frequency-resolution-multiplier').addEventListener('input', event => {
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FREQUENCY_RESOLUTION_MULTIPLIER = parseInt(event.target.value);
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showSpeed();
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})
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document.getElementById('bit-duration-text').addEventListener('input', (event) => {
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FREQUENCY_DURATION = parseInt(event.target.value);
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bitSampleCount = 0;
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samplesPerBit.length = 0;
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showSpeed();
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});
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document.getElementById('max-bits-displayed-on-graph').value= MAX_BITS_DISPLAYED_ON_GRAPH;
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document.getElementById('max-bits-displayed-on-graph').addEventListener('input', (event) => {
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MAX_BITS_DISPLAYED_ON_GRAPH = parseInt(event.target.value);
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})
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document.getElementById('bit-duration-text').value = FREQUENCY_DURATION;
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document.getElementById('amplitude-threshold-text').value = Math.floor(FREQUENCY_THRESHOLD_PERCENT * 100);
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FREQUENCY_THRESHOLD = Math.floor(FREQUENCY_THRESHOLD_PERCENT * 255);
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document.getElementById('maximum-frequency').value = MAXIMUM_FREQUENCY;
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document.getElementById('minimum-frequency').value = MINIMUM_FREQUENCY;
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document.getElementById('last-bit-percent').value = Math.floor(LAST_BIT_PERCENT * 100);
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document.getElementById('fft-size-power-text').value = FFT_POWER;
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document.getElementById('smoothing-time-constant-text').value = SMOOTHING_TIME_CONSTANT.toFixed(2);
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document.getElementById('amplitude-threshold-text').addEventListener('input', (event) => {
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FREQUENCY_THRESHOLD_PERCENT = parseInt(event.target.value) / 100;
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FREQUENCY_THRESHOLD = Math.floor(FREQUENCY_THRESHOLD_PERCENT * 255);
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});
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document.getElementById('maximum-frequency').addEventListener('input', (event) => {
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MAXIMUM_FREQUENCY = parseInt(event.target.value);
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showSpeed();
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});
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document.getElementById('minimum-frequency').addEventListener('input', (event) => {
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MINIMUM_FREQUENCY = parseInt(event.target.value);
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showSpeed();
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});
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document.getElementById('last-bit-percent').addEventListener('input', (event) => {
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LAST_BIT_PERCENT = parseInt(event.target.value) / 100;
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});
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document.getElementById('fft-size-power-text').addEventListener('input', (event) => {
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FFT_POWER = parseInt(event.target.value);
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if(analyser) analyser.fftSize = 2 ** FFT_POWER;
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updateFrequencyResolution();
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resetGraphData();
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});
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updateFrequencyResolution();
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document.getElementById('smoothing-time-constant-text').addEventListener('input', event => {
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SMOOTHING_TIME_CONSTANT = parseFloat(event.target.value);
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if(analyser) analyser.smoothingTimeConstant = SMOOTHING_TIME_CONSTANT;
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});
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document.getElementById('audio-context-sample-rate').innerText = getAudioContext().sampleRate.toLocaleString();
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// wire up events
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sendButton.addEventListener('click', handleSendButtonClick);
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isListeningCheckbox.addEventListener('click', handleListeningCheckbox);
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textToSend.addEventListener('keypress', handleTextToSendKeypress);
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showSpeed();
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}
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function updateFrequencyResolution() {
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const sampleRate = getAudioContext().sampleRate;
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const fftSize = 2 ** FFT_POWER;
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const frequencyResolution = sampleRate / fftSize;
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const frequencyCount = (sampleRate/2) / frequencyResolution;
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document.getElementById('frequency-resolution').innerText = frequencyResolution.toFixed(2);
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document.getElementById('frequency-count').innerText = frequencyCount.toFixed(2);
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showSpeed();
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}
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function showSpeed() {
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const segmentsPerSecond = 1000 / FREQUENCY_DURATION;
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const bitsPerSegment = getBitFrequencies().length;
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const baud = bitsPerSegment * segmentsPerSecond;
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const bytes = baud / 8;
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document.getElementById('durations-per-second').innerText = segmentsPerSecond.toFixed(2);
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document.getElementById('bits-per-duration').innerText = bitsPerSegment;
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document.getElementById('data-transfer-speed-bits-per-second').innerText = baud.toFixed(2);
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document.getElementById('data-transfer-speed-bytes-per-second').innerText = bytes.toFixed(2);
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}
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function handleTextToSendKeypress(event) {
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var keyCode = event.which || event.keyCode;
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var bits = keyCode.toString(2)
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.padStart(8, '0')
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.split('')
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.map(Number);
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sendBits(bits);
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}
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function getFrequency(bit) {
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return bit ? MAXIMUM_FREQUENCY : MINIMUM_FREQUENCY;
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}
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function getBitFrequencies() {
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var audioContext = getAudioContext();
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const sampleRate = audioContext.sampleRate;
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const fftSize = 2 ** FFT_POWER;
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const frequencyResolution = sampleRate / fftSize;
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const frequencies = [];
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const pairStep = frequencyResolution * 2 * FREQUENCY_RESOLUTION_MULTIPLIER;
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for(let hz = MINIMUM_FREQUENCY; hz < MAXIMUM_FREQUENCY; hz+= pairStep * 2) {
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const low = hz;
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const high = hz + frequencyResolution * FREQUENCY_RESOLUTION_MULTIPLIER;
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if(low < MINIMUM_FREQUENCY) continue;
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if(high > MAXIMUM_FREQUENCY) continue;
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frequencies.push([low, high]);
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}
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return frequencies;
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}
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function sendBits(bits) {
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sentDataTextArea.value += bits.join('') + '\n';
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sentDataTextArea.scrollTop = sentDataTextArea.scrollHeight;
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var audioContext = getAudioContext();
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var duration = bits.length * FREQUENCY_DURATION;
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const frequencies = getBitFrequencies();
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const oscillators = [];
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for(let j = 0; j < frequencies.length; j++) {
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var oscillator = audioContext.createOscillator();
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const [low, high] = frequencies[j];
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for(let i = 0; i < bits.length; i++) {
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if(i > 0 && bits[i] === bits[i-1]) continue;
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var offset = ((i * FREQUENCY_DURATION)/1000);
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oscillator.frequency.setValueAtTime(
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bits[i] ? high : low,
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audioContext.currentTime + offset
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);
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}
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oscillator.connect(audioContext.destination);
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oscillators.push(oscillator);
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}
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resumeGraph();
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oscillators.forEach(o => o.start());
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window.setTimeout(function() {
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oscillators.forEach(o => o.stop());
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}, duration);
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}
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function stopGraph() {
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PAUSE = true;
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if(sampleIntervalId) {
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window.clearInterval(sampleIntervalId);
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sampleIntervalId = undefined;
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}
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}
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function resumeGraph() {
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if(isListeningCheckbox.checked) {
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if(PAUSE) {
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PAUSE = false;
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sampleIntervalId = window.setInterval(collectSample, SAMPLE_DELAY_MS);
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resetGraphData();
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requestAnimationFrame(drawFrequencyData);
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} else {
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PAUSE = false;
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}
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} else {
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PAUSE = false;
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}
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}
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function collectSample() {
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const time = performance.now();
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const frequencies = new Uint8Array(analyser.frequencyBinCount);
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const length = audioContext.sampleRate / analyser.fftSize;
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const {
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hasSignal: hadPriorSignal,
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streamStarted: initialStreamStart = time,
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streamEnded: priorStreamEnded,
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bitIndex: priorBitIndex = -1
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} = frequencyOverTime[0] ?? {}
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analyser.getByteFrequencyData(frequencies);
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const data = { time, frequencies, length };
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let hasSignal = false;
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data.pairs = getBitFrequencies().map(([low, high], i) => {
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const lowAmp = frequencies[Math.round(low / length)];
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const highAmp = frequencies[Math.round(high / length)];
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const isLow = lowAmp > FREQUENCY_THRESHOLD;
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const isHigh = highAmp > FREQUENCY_THRESHOLD;
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if(isLow || isHigh ) hasSignal = true;
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return {
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channel: i,
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lowHz: low,
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highHz: high,
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isHigh: (isHigh && !isLow) || highAmp > lowAmp
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};
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});
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data.hasSignal = hasSignal;
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if(hasSignal) {
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if(hadPriorSignal) {
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// continued bit stream
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data.streamStarted = initialStreamStart;
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} else {
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// new bit stream
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data.streamStarted = time;
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}
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// number of bit in the stream
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const bitIndex = data.bitIndex = Math.floor((time - initialStreamStart) / FREQUENCY_DURATION);
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if(priorBitIndex !== bitIndex && priorBitIndex !== -1) {
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processBitsReceived();
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}
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} else {
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data.bitIndex = -1;
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if(hadPriorSignal) {
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// just stopped
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data.streamStarted = -1;
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data.streamEnded = time;
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// update all prior values with stream end
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for(let i = 0; i < frequencyOverTime.length; i++) {
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if(frequencyOverTime[i].streamStarted === initialStreamStart) {
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frequencyOverTime[i].streamEnded = time;
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}
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}
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processBitsReceived();
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received('\n');
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if(PAUSE_AFTER_END && !pauseTimeoutId) {
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pauseTimeoutId = window.setTimeout(() => {
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pauseTimeoutId = undefined;
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if(PAUSE_AFTER_END) stopGraph();
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}, FREQUENCY_DURATION * 1.5);
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}
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} else {
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// continued stopping (or never started)
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data.streamEnded = priorStreamEnded;
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}
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}
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frequencyOverTime.unshift(data);
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truncateGraphData();
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}
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function processBitsReceived() {
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const {
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bitIndex,
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streamStarted,
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pairs: {
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length: channelCount
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}
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} = frequencyOverTime[0];
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const bits = frequencyOverTime.filter(f =>
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f.bitIndex === bitIndex &&
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f.streamStarted === streamStarted
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);
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const bitEnded = bits[0].time;
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const bitStarted = streamStarted + (FREQUENCY_DURATION * bitIndex);
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const bitDuration = bitEnded - bitStarted;
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if(bitDuration < FREQUENCY_DURATION * LAST_BIT_PERCENT) {
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return;
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}
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const channels = new Array(channelCount).fill(0);
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const maxHighBits = bits.reduce((max, { pairs: { length } }) => max > length ? max : length, 0);
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bits.forEach(({pairs}) => {
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pairs.forEach(({ isHigh }, i) => {
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if(isHigh) channels[i]++;
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})
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});
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const bitString = channels.map(count => count >= (maxHighBits / 2) ? '1' : '0').join('');
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received(bitString + '\n');
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}
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function resetGraphData() {
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frequencyOverTime.length = 0;
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bitStart.length = 0;
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}
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function truncateGraphData() {
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const duration = FREQUENCY_DURATION * MAX_BITS_DISPLAYED_ON_GRAPH;
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const now = performance.now();
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let length = frequencyOverTime.length;
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while(length !== 0) {
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const time = frequencyOverTime[length-1].time;
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if(now - time > duration) length--;
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else break;
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}
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if(length !== frequencyOverTime.length) {
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frequencyOverTime.length = length;
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bitStart.length = length;
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}
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}
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function getAudioContext() {
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if(!audioContext) {
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audioContext = new (window.AudioContext || webkitAudioContext)();
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}
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if(audioContext.state === 'suspended') {
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audioContext.resume();
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}
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return audioContext;
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}
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function handleSendButtonClick() {
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var audioContext = getAudioContext();
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var oscillator = audioContext.createOscillator();
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oscillator.frequency.setValueAtTime(FREQUENCY_TONE, audioContext.currentTime);
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oscillator.connect(audioContext.destination);
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oscillator.start();
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window.setTimeout(function() { oscillator.stop(); }, 500);
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}
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function handleListeningCheckbox(e) {
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stopGraph();
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var audioContext = getAudioContext();
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function handleMicrophoneOn(stream) {
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microphoneStream = stream;
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microphoneNode = audioContext.createMediaStreamSource(stream);
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analyser = audioContext.createAnalyser();
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analyser.smoothingTimeConstant = SMOOTHING_TIME_CONSTANT;
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analyser.fftSize = 2 ** FFT_POWER;
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microphoneNode.connect(analyser);
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resumeGraph();
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}
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function handleMicrophoneError(error) {
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console.error('Microphone Error', error);
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}
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if(e.target.checked) {
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navigator.mediaDevices
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.getUserMedia({
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audio: {
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mandatory: {
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autoGainControl: false,
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echoCancellation: false,
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noiseSuppression: false,
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suppressLocalAudioPlayback: false,
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voiceIsolation: false
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},
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optional: []
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}
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})
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.then(handleMicrophoneOn)
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.catch(handleMicrophoneError)
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} else {
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if(microphoneStream) {
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microphoneStream.getTracks().forEach(track => track.stop());
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microphoneStream = undefined;
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}
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if(analyser && microphoneNode) {
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try {
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analyser.disconnect(microphoneNode);
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} catch(e) {
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}
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microphoneNode = undefined;
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analyser = undefined;
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}
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}
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}
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function received(value) {
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receivedDataTextarea.value += value;
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receivedDataTextarea.scrollTop = receivedDataTextarea.scrollHeight;
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}
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let bitStarted;
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let lastBitStarted;
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let bitEnded;
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let bitHighStrength = [];
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let bitLowStrength = [];
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let lastBitIndex = 0;
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function canHear(hz, {frequencies, length}) {
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var i = Math.round(hz / length);
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return frequencies[i] > FREQUENCY_THRESHOLD;
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}
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function amplitude(hz, {frequencies, length}) {
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var i = Math.round(hz / length);
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return frequencies[i];
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}
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const sum = (total, value) => total + value;
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function evaluateBit(highBits, lowBits) {
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let highCount = highBits.reduce(
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(count, highAmplitude, i) =>
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count += highAmplitude > lowBits[i] ? 1 : 0
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, 0
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);
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return highCount >= (highBits.length / 2) ? '1' : '0';
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}
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function avgLabel(array) {
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const values = array.filter(v => v > 0);
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if(values.length === 0) return 'N/A';
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return (values.reduce((t, v) => t + v, 0) / values.length).toFixed(2)
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}
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function drawBitDurationLines(ctx, color) {
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const { width, height } = receivedGraph;
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const newest = frequencyOverTime[0].time;
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const duration = FREQUENCY_DURATION * MAX_BITS_DISPLAYED_ON_GRAPH;
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const streamTimes = frequencyOverTime.filter((v, i, a) => {
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return v.streamStarted !== -1 && (
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i === 0 ||
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a[i-1].streamStarted !== v.streamStarted
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)
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});
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ctx.strokeStyle = color;
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streamTimes.forEach(({ streamStarted, streamEnded = newest}) => {
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for(let time = streamStarted; time < streamEnded; time += FREQUENCY_DURATION) {
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if(newest - time > duration) continue;
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const x = ((newest - time) / duration) * width;
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ctx.beginPath();
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ctx.moveTo(x, 0);
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ctx.lineTo(x, height);
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ctx.stroke();
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}
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// write end as well
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const x = ((newest - streamEnded) / duration) * width;
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ctx.beginPath();
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ctx.moveTo(x, 0);
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ctx.lineTo(x, height);
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ctx.stroke();
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});
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}
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function drawBitStart(ctx, color) {
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const { width, height } = receivedGraph;
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const newest = frequencyOverTime[0].time;
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const duration = FREQUENCY_DURATION * MAX_BITS_DISPLAYED_ON_GRAPH;
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ctx.strokeStyle = color;
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for(let i = 0; i < bitStart.length; i++) {
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if(!bitStart[i]) continue;
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const {time} = frequencyOverTime[i];
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if(newest - time > duration) continue;
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const x = ((newest - time) / duration) * width;
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ctx.beginPath();
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ctx.moveTo(x, 0);
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ctx.lineTo(x, height);
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ctx.stroke();
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}
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}
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function hzAmplitude(hz, length, frequencies) {
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var index = Math.round(hz / length);
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return frequencies[index];
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}
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function getPercentY(percent) {
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const { height } = receivedGraph;
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return (1 - percent) * height;
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}
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function drawFrequencyLineGraph(ctx, hz, color) {
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const { width, height } = receivedGraph;
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const newest = frequencyOverTime[0].time;
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const duration = FREQUENCY_DURATION * MAX_BITS_DISPLAYED_ON_GRAPH;
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ctx.strokeStyle = color;
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ctx.beginPath();
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for(let i = 0; i < frequencyOverTime.length; i++) {
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const {frequencies, time, length} = frequencyOverTime[i];
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const x = getTimeX(time, newest);
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if(x === -1) continue;
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const amplitude = hzAmplitude(hz, length, frequencies);
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const y = getPercentY(amplitude / MAX_DATA);
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if(i === 0) ctx.moveTo(x, y); else ctx.lineTo(x, y);
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}
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ctx.stroke();
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}
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function drawFrequencyDots(ctx, hz, color) {
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const newest = frequencyOverTime[0].time;
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const radius = 2;
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const border = 0.5;
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ctx.fillStyle = color;
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ctx.strokeStyle = 'white';
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ctx.lineWidth = border;
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const fullCircle = 2 * Math.PI;
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for(let i = 0; i < frequencyOverTime.length; i++) {
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const {frequencies, time, length} = frequencyOverTime[i];
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const x = getTimeX(time, newest);
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if(x === -1) continue;
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const amplitude = hzAmplitude(hz, length, frequencies);
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const y = getPercentY(amplitude / MAX_DATA);
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ctx.beginPath();
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ctx.arc(x, y, radius, 0, fullCircle);
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ctx.fill();
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ctx.beginPath();
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ctx.arc(x, y, radius + border, 0, fullCircle);
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ctx.stroke();
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}
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}
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function getTimeX(time, newest) {
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const { width } = receivedGraph;
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const duration = FREQUENCY_DURATION * MAX_BITS_DISPLAYED_ON_GRAPH;
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if(newest - time > duration) return -1;
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return ((newest - time) / duration) * width;
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}
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function drawFrequencyData() {
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if(PAUSE) return;
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if(frequencyOverTime.length === 0) {
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requestAnimationFrame(drawFrequencyData);
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return;
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}
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const ctx = receivedGraph.getContext('2d');
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const { width, height } = receivedGraph;
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ctx.fillStyle = 'black';
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ctx.fillRect(0, 0, width, height);
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const thresholdY = (1 - (FREQUENCY_THRESHOLD/MAX_DATA)) * height;
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ctx.strokeStyle = 'grey';
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ctx.beginPath();
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ctx.moveTo(0, thresholdY);
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ctx.lineTo(width, thresholdY);
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ctx.stroke();
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drawBitDurationLines(ctx, 'yellow');
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drawBitStart(ctx, 'green');
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const frequencies = getBitFrequencies();
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// frequencies.forEach(([low, high]) => {
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// drawFrequencyDots(ctx, high, 'red');
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// drawFrequencyDots(ctx, low, 'blue');
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// });
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frequencies.forEach(([low, high]) => {
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drawFrequencyLineGraph(ctx, high, 'red');
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drawFrequencyLineGraph(ctx, low, 'blue');
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});
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requestAnimationFrame(drawFrequencyData);
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}
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function drawReceivedData() {
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const ctx = receivedGraph.getContext('2d');
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const { width, height } = receivedGraph;
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const segmentWidth = (1 / MAX_BITS_DISPLAYED_ON_GRAPH) * width;
|
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ctx.clearRect(0, 0, width, height);
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const sorted = receivedData.slice().sort((a, b) => a - b);
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const min = sorted[0];
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const max = sorted[sorted.length - 1];
|
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const range = max - min;
|
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ctx.beginPath();
|
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for(let i = 0; i < MAX_BITS_DISPLAYED_ON_GRAPH && i < receivedData.length; i++) {
|
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const value = receivedData[i];
|
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const y = (1-(value / range)) * height;
|
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if(i === 0) {
|
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ctx.moveTo(0, y);
|
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} else {
|
|
ctx.lineTo(segmentWidth * i, y)
|
|
}
|
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}
|
|
ctx.stroke();
|
|
}
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window.addEventListener('load', handleWindowLoad); |