De-XHR-ify (#116)

* 2 new examples for looping and playbackrate * Rename decode-audio-data * Separate files for scripts * Use fetch() in decodeaudiodata/callback * Use fetch() in script-processor-node * Use fetch() in voice-change-o-matic * Delete unused polyfill respond.js * Apply suggestions from code review Co-authored-by: Jean-Yves Perrier <jypenator@gmail.com> * Review comments * Apply suggestions from code review Co-authored-by: Jean-Yves Perrier <jypenator@gmail.com> * Init audio context on play --------- Co-authored-by: Jean-Yves Perrier <jypenator@gmail.com>
mdn · Nov 20, 2023 · f58f98b · f58f98b
1 parent 41775fb
commit f58f98b
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Showing 21 changed files with 610 additions and 532 deletions.
diff --git a/audio-buffer-source-node/loop/index.html b/audio-buffer-source-node/loop/index.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width" />
+
+    <title>Web Audio API examples: looping a track</title>
+
+    <script src="script.js" defer></script>
+  </head>
+
+  <body>
+    <h1>Web Audio API examples: looping a track</h1>
+
+    <button id="play">Play</button>
+    <button id="stop" disabled>Stop</button>
+
+    <h2>Set loop start and loop end</h2>
+    <input
+      id="loopstart-control"
+      type="range"
+      min="0"
+      max="20"
+      step="1"
+      value="0"
+      disabled />
+    Starts at <span id="loopstart-value">0</span> s.
+    <br />
+    <input
+      id="loopend-control"
+      type="range"
+      min="0"
+      max="20"
+      step="1"
+      value="0"
+      disabled />
+    Stops at <span id="loopend-value">0</span> s.
+    <p>
+      If the stop time is lower or equal to the start time, it'll loop over the
+      whole track.
+    </p>
+  </body>
+</html>
diff --git a/audio-buffer-source-node/loop/rnb-lofi-melody-loop.wav b/audio-buffer-source-node/loop/rnb-lofi-melody-loop.wav
diff --git a/audio-buffer-source-node/loop/script.js b/audio-buffer-source-node/loop/script.js
@@ -0,0 +1,62 @@
+let audioCtx;
+let buffer;
+let source;
+
+const play = document.getElementById("play");
+const stop = document.getElementById("stop");
+
+const loopstartControl = document.getElementById("loopstart-control");
+const loopstartValue = document.getElementById("loopstart-value");
+
+const loopendControl = document.getElementById("loopend-control");
+const loopendValue = document.getElementById("loopend-value");
+
+async function loadAudio() {
+  try {
+    // Load an audio file
+    const response = await fetch("rnb-lofi-melody-loop.wav");
+    // Decode it
+    buffer = await audioCtx.decodeAudioData(await response.arrayBuffer());
+    const max = Math.floor(buffer.duration);
+    loopstartControl.setAttribute("max", max);
+    loopendControl.setAttribute("max", max);
+  } catch (err) {
+    console.error(`Unable to fetch the audio file. Error: ${err.message}`);
+  }
+}
+
+play.addEventListener("click", async () => {
+  if (!audioCtx) {
+    audioCtx = new AudioContext();
+    await loadAudio();
+  }
+  source = audioCtx.createBufferSource();
+  source.buffer = buffer;
+  source.connect(audioCtx.destination);
+  source.loop = true;
+  source.loopStart = loopstartControl.value;
+  source.loopEnd = loopendControl.value;
+  source.start();
+  play.disabled = true;
+  stop.disabled = false;
+  loopstartControl.disabled = false;
+  loopendControl.disabled = false;
+});
+
+stop.addEventListener("click", () => {
+  source.stop();
+  play.disabled = false;
+  stop.disabled = true;
+  loopstartControl.disabled = true;
+  loopendControl.disabled = true;
+});
+
+loopstartControl.addEventListener("input", () => {
+  source.loopStart = loopstartControl.value;
+  loopstartValue.textContent = loopstartControl.value;
+});
+
+loopendControl.addEventListener("input", () => {
+  source.loopEnd = loopendControl.value;
+  loopendValue.textContent = loopendControl.value;
+});
diff --git a/audio-buffer-source-node/playbackrate/index.html b/audio-buffer-source-node/playbackrate/index.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width" />
+
+    <title>Web Audio API examples: setting playback rate</title>
+
+    <script src="script.js" defer></script>
+  </head>
+
+  <body>
+    <h1>Web Audio API examples: setting playback rate</h1>
+
+    <button id="play">Play</button>
+    <button id="stop" disabled>Stop</button>
+
+    <h2>Set playback rate</h2>
+    <input
+      id="playback-rate-control"
+      type="range"
+      min="0.25"
+      max="3"
+      step="0.05"
+      value="1"
+      disabled />
+    <span id="playback-rate-value">1.0</span>  × the original rate.
+  </body>
+</html>
diff --git a/audio-buffer-source-node/playbackrate/rnb-lofi-melody-loop.wav b/audio-buffer-source-node/playbackrate/rnb-lofi-melody-loop.wav
diff --git a/audio-buffer-source-node/playbackrate/script.js b/audio-buffer-source-node/playbackrate/script.js
@@ -0,0 +1,48 @@
+let audioCtx;
+let buffer;
+let source;
+
+const play = document.getElementById("play");
+const stop = document.getElementById("stop");
+
+const playbackControl = document.getElementById("playback-rate-control");
+const playbackValue = document.getElementById("playback-rate-value");
+
+async function loadAudio() {
+  try {
+    // Load an audio file
+    const response = await fetch("rnb-lofi-melody-loop.wav");
+    // Decode it
+    buffer = await audioCtx.decodeAudioData(await response.arrayBuffer());
+  } catch (err) {
+    console.error(`Unable to fetch the audio file. Error: ${err.message}`);
+  }
+}
+
+play.addEventListener("click", async () => {
+  if (!audioCtx) {
+    audioCtx = new AudioContext();
+    await loadAudio();
+  }
+  source = audioCtx.createBufferSource();
+  source.buffer = buffer;
+  source.connect(audioCtx.destination);
+  source.loop = true;
+  source.playbackRate.value = playbackControl.value;
+  source.start();
+  play.disabled = true;
+  stop.disabled = false;
+  playbackControl.disabled = false;
+});
+
+stop.addEventListener("click", () => {
+  source.stop();
+  play.disabled = false;
+  stop.disabled = true;
+  playbackControl.disabled = true;
+});
+
+playbackControl.oninput = () => {
+  source.playbackRate.value = playbackControl.value;
+  playbackValue.textContent = playbackControl.value;
+};
diff --git a/decode-audio-data/callback/index.html b/decode-audio-data/callback/index.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width" />
+    <title>Web Audio API examples: decodeAudioData() with callback</title>
+    <script src="script.js" defer></script>
+  </head>
+
+  <body>
+    <h1>Web Audio API examples: decodeAudioData() with callback</h1>
+
+    <button id="play">Play</button>
+    <button id="stop" disabled>Stop</button>
+
+    <h2>Set playback rate</h2>
+    <input
+      id="playback-rate-control"
+      type="range"
+      min="0.25"
+      max="3"
+      step="0.05"
+      value="1"
+      disabled />
+    <span id="playback-rate-value">1.0</span>
+
+    <h2>Set loop start and loop end</h2>
+    <input
+      id="loopstart-control"
+      type="range"
+      min="0"
+      max="20"
+      step="1"
+      value="0"
+      disabled />
+    <span id="loopstart-value">0</span>
+
+    <input
+      id="loopend-control"
+      type="range"
+      min="0"
+      max="20"
+      step="1"
+      value="0"
+      disabled />
+    <span id="loopend-value">0</span>
+
+    <p>
+      If the stop time is lower or equal to the start time, it'll loop over the
+      whole track.
+    </p>
+  </body>
+</html>
diff --git a/decode-audio-data/callback/script.js b/decode-audio-data/callback/script.js
@@ -0,0 +1,81 @@
+let audioCtx;
+let buffer;
+let source;
+
+// Get UI elements
+const play = document.getElementById("play");
+const stop = document.getElementById("stop");
+
+const playbackControl = document.getElementById("playback-rate-control");
+const playbackValue = document.getElementById("playback-rate-value");
+
+const loopstartControl = document.getElementById("loopstart-control");
+const loopstartValue = document.getElementById("loopstart-value");
+
+const loopendControl = document.getElementById("loopend-control");
+const loopendValue = document.getElementById("loopend-value");
+
+function playBuffer() {
+  source = audioCtx.createBufferSource();
+  source.buffer = buffer;
+  source.playbackRate.value = playbackControl.value;
+  source.connect(audioCtx.destination);
+  source.loop = true;
+  source.loopStart = loopstartControl.value;
+  source.loopEnd = loopendControl.value;
+  source.start();
+  play.disabled = true;
+  stop.disabled = false;
+  playbackControl.disabled = false;
+  loopstartControl.disabled = false;
+  loopendControl.disabled = false;
+}
+
+async function loadAudio() {
+  try {
+    const response = await fetch("viper.mp3");
+    audioCtx.decodeAudioData(await response.arrayBuffer(), (buf) => {
+      // executes when buffer has been decoded
+      buffer = buf;
+      const max = Math.floor(buf.duration);
+      loopstartControl.max = max;
+      loopendControl.max = max;
+      play.disabled = false; // buffer loaded, enable play button
+      playBuffer();
+    });
+  } catch (err) {
+    console.error(`Unable to fetch the audio file. Error: ${err.message}`);
+  }
+}
+
+play.addEventListener("click", async () => {
+  if (!audioCtx) {
+    audioCtx = new AudioContext();
+    await loadAudio();
+  } else {
+    playBuffer();
+  }
+});
+
+stop.addEventListener("click", () => {
+  source.stop();
+  play.disabled = false;
+  playbackControl.disabled = true;
+  loopstartControl.disabled = true;
+  loopendControl.disabled = true;
+});
+
+playbackControl.addEventListener("input", () => {
+  source.playbackRate.value = playbackControl.value;
+  playbackValue.textContent = playbackControl.value;
+});
+
+loopstartControl.addEventListener("input", () => {
+  source.loopStart = loopstartControl.value;
+  loopstartValue.textContent = loopstartControl.value;
+});
+
+loopendControl.oninput = () => {
+  source.loopEnd = loopendControl.value;
+  loopendValue.textContent = loopendControl.value;
+};
diff --git a/decode-audio-data/viper.mp3 → decode-audio-data/callback/viper.mp3 b/decode-audio-data/viper.mp3 → decode-audio-data/callback/viper.mp3
diff --git a/decode-audio-data/viper.ogg → decode-audio-data/callback/viper.ogg b/decode-audio-data/viper.ogg → decode-audio-data/callback/viper.ogg