Initial Commit

packages/media/audio/audio-codecs/src/codecs/mp3.ts

@@ -0,0 +1,29 @@
+import { createWasmCodec } from "./wasm-base.js";
+
+function mp3Magic(bytes: Uint8Array): boolean {
+    if (bytes.byteLength < 2) return false;
+    // MPEG audio sync word (11 bits) — 0xFFE mask on first two bytes
+    if (bytes[0] === 0xff && (bytes[1]! & 0xe0) === 0xe0) return true;
+    // ID3v2 prefix requires three bytes
+    if (
+        bytes.byteLength >= 3 &&
+        bytes[0] === 0x49 &&
+        bytes[1] === 0x44 &&
+        bytes[2] === 0x33
+    )
+        return true;
+    return false;
+}
+
+/** Lazy MP3 codec backed by `@audio/decode-mp3`. */
+export const Mp3Codec = createWasmCodec({
+    name: "mp3",
+    extensions: ["mp3", "mpeg"],
+    mimeTypes: ["audio/mpeg", "audio/mp3"],
+    module: "@audio/decode-mp3",
+    magic: mp3Magic,
+    supportsEncode: true,
+    load: () =>
+        // @ts-expect-error optional dependency resolved at runtime
+        import("@audio/decode-mp3"),
+});