refactor: formaliza formatos de áudio e alinhamento PCM

tests/js/pcm-player.test.mjs

@@ -223,3 +223,35 @@ test("late PCM after stop is ignored", async () => {
   assert.equal(player.playing, false);
   assert.equal(player.sources.size, 0);
 });
+
+
+test("uses the output sample rate declared by the server", async () => {
+  const context = new FakeAudioContext();
+  const player = new PCMPlayer({ audioContext: context });
+  player.configure({ encoding: "pcm_s16le", sample_rate: 24000, channels: 1 });
+  await player.enqueue(pcm([100, 200, 300, 400]));
+  assert.equal(player.sampleRate, 24000);
+  assert.equal(context.sources[0].buffer.duration, 4 / 24000);
+});
+
+for (const format of [
+  undefined,
+  { encoding: "wav", sample_rate: 48000, channels: 1 },
+  { encoding: "pcm_s16le", sample_rate: 48000, channels: 2 },
+  { encoding: "pcm_s16le", sample_rate: "48000", channels: 1 },
+  { encoding: "pcm_s16le", sample_rate: 0, channels: 1 },
+  { encoding: "pcm_s16le", sample_rate: 192000, channels: 1 },
+]) {
+  test(`rejects unsupported playback metadata: ${JSON.stringify(format)}`, () => {
+    const player = new PCMPlayer({ audioContext: new FakeAudioContext() });
+    assert.throws(() => player.configure(format), /Formato de áudio/);
+  });
+}
+
+test("rejects format changes while audio is scheduled", async () => {
+  const player = new PCMPlayer({ audioContext: new FakeAudioContext() });
+  await player.enqueue(pcm([100, 200]));
+  assert.throws(() => player.configure({
+    encoding: "pcm_s16le", sample_rate: 24000, channels: 1,
+  }), /durante a reprodução/);
+});