Fully update MP3 demuxer to use new packet reading system & mutex, add MP3 reading tests

test/browser/decode.test.ts

@@ -0,0 +1,22 @@
+import { expect, test } from 'vitest';
+import { Input } from '../../src/input.js';
+import { UrlSource } from '../../src/source.js';
+import { ALL_FORMATS } from '../../src/input-format.js';
+import { assert } from '../../src/misc.js';
+import { AudioSampleCursor } from '../../src/cursors.js';
+
+test('MP3 decoding', async () => {
+	using input = new Input({
+		source: new UrlSource('/AudacityTest1.mp3'),
+		formats: ALL_FORMATS,
+	});
+
+	const audioTrack = await input.getPrimaryAudioTrack();
+	assert(audioTrack);
+
+	const cursor = new AudioSampleCursor(audioTrack);
+	const sample = await cursor.seekToFirst();
+	expect(sample).not.toBe(null);
+	expect(sample!.timestamp).toBe(0);
+	expect(sample!.duration).toBeCloseTo(1152 / audioTrack.sampleRate);
+});