init spoopy sequencer
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commit
37141cd25e
1 changed files with 221 additions and 0 deletions
221
index.html
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221
index.html
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<!DOCTYPE html>
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<html lang="en"><head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="ROBOTS" content="NOINDEX, NOFOLLOW">
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<title>wambam</title>
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<meta name="description" content="wambam">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<style>
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body {
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max-width: 50em;
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margin: 1em auto;
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line-height: 1.5;
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word-wrap: break-word;
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padding: 0 1em;
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background: #111111;
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color: lightgray;
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}
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</style>
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<script>
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const AudioContext = window.AudioContext || window.webkitAudioContext;
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const tracks = [];
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const lookahead = 25.0; // ms to call scheduler
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const scheduleAheadTime = 0.1; // sec
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const beatsPerMeasure = 12;
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let buffers = {};
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let filters = {};
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let instruments = {};
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let notesInQueue = [];
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let tempo = 60.0;
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let audioContext;
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let osc;
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let timer;
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const startContext = () => {
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audioContext = new AudioContext();
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initBuffers();
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defaultPlayer = instruments["💀"]
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}
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const initBuffers = () => {
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const skullLength = .1500;
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const wormLength = .4;
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buffers.skull = new AudioBuffer({
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length: audioContext.sampleRate * skullLength,
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sampleRate: audioContext.sampleRate,
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});
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let skullData = buffers.skull.getChannelData(0);
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skullData.forEach((_, i) => skullData[i] = Math.random() * 2 - 1);
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buffers.worm = new AudioBuffer({
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length: audioContext.sampleRate * wormLength,
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sampleRate: audioContext.sampleRate,
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});
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let wormData = buffers.worm.getChannelData(0);
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wormData.forEach((_, i) => wormData[i] = Math.random() - 1);
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filters.lurk = new BiquadFilterNode(audioContext, {
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type: "bandpass",
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frequency: 2000,
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})
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instruments = {
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"💀": playBuffer(buffers.skull),
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"🪱": playBuffer(buffers.worm),
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"🕷️": playBufferWithFilter(buffers.skull, filters.lurk),
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"🐞": playBufferWithFilter(buffers.worm, filters.lurk)
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}
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}
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const replaceBeginButton = () => {
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document.getElementById("beginButton").style.display = "none";
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document.getElementById("playButton").style.display = "block";
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document.getElementById("pauseButton").style.display = "block";
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document.getElementById("addTrackButton").style.display = "block";
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document.getElementById("tempoSlider").style.display = "block";
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document.getElementById("tempo").addEventListener("input", (event) => tempo = parseInt(event.target.value, 10), false);
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}
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const play = () => {
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console.log("playing!");
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audioContext.resume();
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scheduler();
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}
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const pause = () => {
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console.log("paused!");
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clearTimeout(timer);
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audioContext.suspend();
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}
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const playBuffer = (buffer) => (time) => {
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const player = new AudioBufferSourceNode(audioContext, {buffer});
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player.connect(audioContext.destination);
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player.start(time)
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}
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const playBufferWithFilter = (buffer, filter) => (time) => {
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const player = new AudioBufferSourceNode(audioContext, { buffer});
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player.connect(filter).connect(audioContext.destination);
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player.start(time);
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}
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function Track(idx, curTime) {
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this.play = defaultPlayer;
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this.hits= Array(beatsPerMeasure).fill(false);
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this.tempoModifier= idx + 1;
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this.nextNoteTime= curTime;
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this.currentNote= 0;
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this.nextNote= () => {
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const secondsPerBeat = 60.0 / tempo * this.tempoModifier / beatsPerMeasure;
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this.nextNoteTime += secondsPerBeat;
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this.currentNote = (this.currentNote + 1) % beatsPerMeasure;
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};
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this.changePlayer = (key) => {
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this.play = instruments[key] || defaultPlayer;
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};
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this.setHit = (beat, value) => {
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this.hits[beat] = value || false;
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};
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this.scheduleNote= (beatNumber, time) => {
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notesInQueue.push({ track: idx, note: beatNumber});
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if (this.hits[beatNumber] == true) this.play();
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};
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}
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const addTrack = () => {
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idx = tracks.length;
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curTime = audioContext.currentTime || 0;
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tracks.push(new Track(idx, curTime));
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return idx;
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}
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const scheduler = () => {
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tracks.forEach(track => {
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while(track.nextNoteTime < audioContext.currentTime + scheduleAheadTime) {
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track.scheduleNote(track.currentNote, track.nextNoteTime);
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track.nextNote();
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}
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})
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timer = setTimeout(scheduler, lookahead);
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}
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const makeTrackTableRow = (idx) => {
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const table = document.getElementById("sequencer");
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const row = document.createElement("tr");
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row.id = `t${idx}`;
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const rowLabel = document.createElement("td");
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rowLabel.innerText = `t${idx}`;
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row.dataset.curBeat = 0;
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row.append(rowLabel);
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Object.keys(instruments).forEach((inst, i) => {
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const radio = document.createElement("input");
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radio.type = "radio";
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radio.id = inst;
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radio.value = inst;
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radio.name = `t${idx}-inst`;
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if (i == 0) radio.checked = true;
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radio.addEventListener("input", (ev) => {
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tracks[idx].changePlayer(ev.target.value)
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})
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const label = document.createElement("label");
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label.for = inst;
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label.innerText = inst;
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const td = document.createElement("td");
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td.append(radio, label);
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row.append(td);
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});
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for (let beatIdx = 0; beatIdx < beatsPerMeasure; beatIdx++) {
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const td = document.createElement("td");
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const check = document.createElement("input");
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check.type = "checkbox";
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check.id = `t${idx}-${beatIdx}`;
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check.class = `beat-${beatIdx}`;
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check.addEventListener("change", (ev) => {
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tracks[idx].setHit(beatIdx, ev.target.checked);
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});
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check.style
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td.append(check);
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row.append(td);
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}
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table.append(row);
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}
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for (let beatIdx = 0; beatIdx < beatsPerMeasure; beatIdx++) {
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const style = `
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table[data-currentbeat="${beatIdx}"] input.beat-${beatIdx} {
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color: purple;
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}
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`
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}
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</script>
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<body>
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<h1>spoopy sequencer</h1>
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<p>each new track is faster than the last</p>
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<table> <tbody id="sequencer">
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</tbody>
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</table>
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<menu id="playControls">
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<!-- IIFEs! (no fear of parentheses here) -->
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<li id="beginButton"><button onclick="(() =>{startContext(); replaceBeginButton()})()">Begin</button></li>
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<li id="playButton" style="display:none;"><button onclick="(() => play())()">Play</button></li>
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<li id="pauseButton" style="display:none;"><button onclick="(() => pause())()">Pause</button></li>
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<li id="addTrackButton" style="display:none;"><button onclick="(() => {makeTrackTableRow(addTrack())})()">Add Track</button></li>
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<li id="tempoSlider" style="display:none;"><label for="tempo">tempo></label><input type="range" id="tempo" name="tempo" min="30" max="240" value="60" /></li>
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</menu>
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</body></html>
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