fix: compatible with incomplete audio codec string mp4a.40

Author: hughfenghen

packages/av-cliper/src/clips/__tests__/mp4-clip.test.ts

@@ -191,3 +191,14 @@ test('decode incorrectFrameTypeMp4', async () => {
   const { state } = await clip.tick(clip.meta.duration - 30e3);
   expect(state).toBe('success');
 });
+
+const mp4_webav1 = `//${location.host}/video/webav1.mp4`;
+test('compatible with incomplete audio codec string mp4a.40', async () => {
+  const clip = new MP4Clip((await fetch(mp4_webav1)).body!);
+  await clip.ready;
+  const spy = vi.spyOn(console, 'error').mockImplementation(() => {});
+
+  await clip.tick(1e6);
+  expect(spy).not.toHaveBeenCalled();
+  spy.mockRestore();
+});

packages/av-cliper/src/mp4-utils/mp4box-utils.ts

@@ -110,7 +110,10 @@ function parseAudioInfoFromESDSBox(esds: ESDSBoxParser): {
   codec += '.' + decConfDesc.oti.toString(16);
 
   const decSpecInfo = decConfDesc.descs[0];
-  if (decSpecInfo == null) return { codec };
+  if (decSpecInfo == null) {
+    if (codec.endsWith('40')) codec += '.2';
+    return { codec };
+  }
 
   // ref: https://wiki.multimedia.cx/index.php/MPEG-4_Audio#Audio_Specific_Config
   const audioObjectType = (decSpecInfo.data[0] & 0xf8) >> 3;