Aurora SpotiRip desktop and web app

- Spotify playlist, library, album and artist browsing with in-app playback - Song, playlist and album downloads via spotdl with YouTube and Bandcamp fallbacks - Electron desktop app (castLabs Widevine) with a permanent sidebar layout - Linux and Windows packaging scripts
2026-09-25 23:20:57 -05:00
commit 3178b8f4f7
204 changed files with 26045 additions and 0 deletions
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+import {
+  ALL_FORMATS,
+  BlobSource,
+  BufferTarget,
+  canEncodeAudio,
+  Conversion,
+  Input,
+  Mp3OutputFormat,
+  Output,
+  Quality,
+} from "mediabunny";
+import { registerMp3Encoder } from "@mediabunny/mp3-encoder";
+
+type DecodedAudio = {
+  sampleRate: number;
+  channelCount: number;
+  channelData: Float32Array[];
+};
+
+export async function decodeAudio(file: File): Promise<AudioBuffer> {
+  const AudioContextCtor =
+    window.AudioContext ||
+    (window as typeof window & { webkitAudioContext?: typeof AudioContext }).webkitAudioContext;
+  if (!AudioContextCtor) throw new Error("This browser does not support local audio decoding.");
+  const context = new AudioContextCtor();
+  try {
+    const data = await file.arrayBuffer();
+    return await context.decodeAudioData(data.slice(0));
+  } finally {
+    await context.close();
+  }
+}
+
+function clamp16(value: number) {
+  const sample = Math.max(-1, Math.min(1, value));
+  return sample < 0 ? Math.round(sample * 0x8000) : Math.round(sample * 0x7fff);
+}
+
+function writeAscii(view: DataView, offset: number, value: string) {
+  for (let index = 0; index < value.length; index += 1) {
+    view.setUint8(offset + index, value.charCodeAt(index));
+  }
+}
+
+function makeWavBlob(audio: DecodedAudio) {
+  const channels = Math.min(audio.channelCount, 2);
+  const frameCount = audio.channelData[0]?.length || 0;
+  const bytesPerSample = 2;
+  const blockAlign = channels * bytesPerSample;
+  const dataSize = frameCount * blockAlign;
+  const buffer = new ArrayBuffer(44 + dataSize);
+  const view = new DataView(buffer);
+  writeAscii(view, 0, "RIFF");
+  view.setUint32(4, 36 + dataSize, true);
+  writeAscii(view, 8, "WAVE");
+  writeAscii(view, 12, "fmt ");
+  view.setUint32(16, 16, true);
+  view.setUint16(20, 1, true);
+  view.setUint16(22, channels, true);
+  view.setUint32(24, audio.sampleRate, true);
+  view.setUint32(28, audio.sampleRate * blockAlign, true);
+  view.setUint16(32, blockAlign, true);
+  view.setUint16(34, 16, true);
+  writeAscii(view, 36, "data");
+  view.setUint32(40, dataSize, true);
+
+  let offset = 44;
+  for (let frame = 0; frame < frameCount; frame += 1) {
+    for (let channel = 0; channel < channels; channel += 1) {
+      view.setInt16(offset, clamp16(audio.channelData[channel][frame] || 0), true);
+      offset += 2;
+    }
+  }
+
+  return new Blob([buffer], { type: "audio/wav" });
+}
+
+export async function createRecognitionSnippet(file: File) {
+  const decoded = await decodeAudio(file);
+  const duration = decoded.duration;
+  const snippetSeconds = Math.min(12, Math.max(4, duration));
+  const preferredStart = duration > 35 ? 20 : duration > 20 ? 8 : 0;
+  const startSeconds = Math.min(preferredStart, Math.max(0, duration - snippetSeconds));
+  const startFrame = Math.floor(startSeconds * decoded.sampleRate);
+  const snippetFrames = Math.min(
+    Math.floor(snippetSeconds * decoded.sampleRate),
+    Math.max(0, decoded.length - startFrame),
+  );
+  const channels = Math.min(decoded.numberOfChannels, 2);
+  const channelData: Float32Array[] = [];
+  for (let channel = 0; channel < channels; channel += 1) {
+    const source = decoded.getChannelData(channel);
+    channelData.push(source.slice(startFrame, startFrame + snippetFrames));
+  }
+
+  const blob = makeWavBlob({
+    sampleRate: decoded.sampleRate,
+    channelCount: channels,
+    channelData,
+  });
+  return new File([blob], "recognition-snippet.wav", {
+    type: "audio/wav",
+    lastModified: Date.now(),
+  });
+}
+
+export async function convertAudioFileToMp3(file: File, bitrateKbps = 192) {
+  if (file.type === "audio/mpeg" || file.name.toLowerCase().endsWith(".mp3")) {
+    return new Blob([await file.arrayBuffer()], { type: "audio/mpeg" });
+  }
+
+  if (!(await canEncodeAudio("mp3"))) {
+    registerMp3Encoder();
+  }
+
+  const input = new Input({
+    source: new BlobSource(file),
+    formats: ALL_FORMATS,
+  });
+  const target = new BufferTarget();
+  const output = new Output({
+    format: new Mp3OutputFormat(),
+    target,
+  });
+  const conversion = await Conversion.init({
+    input,
+    output,
+    tracks: "primary",
+    video: { discard: true },
+    audio: {
+      codec: "mp3",
+      quality: new Quality({ bitrate: bitrateKbps * 1000 }),
+      forceTranscode: true,
+    },
+  });
+
+  if (!conversion.isValid) {
+    const reasons = conversion.discardedTracks.map((entry) => entry.reason).join(", ");
+    throw new Error(
+      reasons
+        ? `This audio file cannot be converted in this browser (${reasons}).`
+        : "This audio file cannot be converted in this browser.",
+    );
+  }
+
+  await conversion.execute();
+  if (!target.buffer) throw new Error("MP3 conversion produced no output.");
+  return new Blob([target.buffer], { type: "audio/mpeg" });
+}