Fix size in 'stst' box and handle sample description entry

Borewit · Jan 24, 2025 · ca306bf · ca306bf
1 parent a29bcc2
commit ca306bf
Show file tree

Hide file tree

Showing 4 changed files with 26 additions and 14 deletions.
diff --git a/lib/mp4/AtomToken.ts b/lib/mp4/AtomToken.ts
@@ -489,7 +489,7 @@ const stsdHeader: IGetToken<IAtomStsdHeader> = {
 export interface ISampleDescription {
   dataFormat: string;
   dataReferenceIndex: number;
-  description: Uint8Array;
+  description: Uint8Array | undefined;
 }
 
 export interface IAtomStsd {
@@ -499,19 +499,19 @@ export interface IAtomStsd {
 
 /**
  * Atom: Sample Description Atom ('stsd')
- * Ref: https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-25691
+ * Ref: https://developer.apple.com/documentation/quicktime-file-format/sample_description_atom
  */
 class SampleDescriptionTable implements IGetToken<ISampleDescription> {
 
   public constructor(public len: number) {
   }
 
   public get(buf: Uint8Array, off: number): ISampleDescription {
-
+    const descrLen = this.len - 12;
     return {
       dataFormat: FourCcToken.get(buf, off),
       dataReferenceIndex: Token.UINT16_BE.get(buf, off + 10),
-      description: new Token.Uint8ArrayType(this.len - 12).get(buf, off + 12)
+      description: descrLen > 0 ? new Token.Uint8ArrayType(descrLen).get(buf, off + 12) : undefined
     };
   }
 }
@@ -535,7 +535,7 @@ export class StsdAtom implements IGetToken<IAtomStsd> {
     for (let n = 0; n < header.numberOfEntries; ++n) {
       const size = Token.UINT32_BE.get(buf, off); // Sample description size
       off += Token.UINT32_BE.len;
-      table.push(new SampleDescriptionTable(size).get(buf, off));
+      table.push(new SampleDescriptionTable(size - Token.UINT32_BE.len).get(buf, off));
       off += size;
     }
 

diff --git a/lib/mp4/MP4Parser.ts b/lib/mp4/MP4Parser.ts
@@ -5,11 +5,11 @@ import { BasicParser } from '../common/BasicParser.js';
 import { Genres } from '../id3v1/ID3v1Parser.js';
 import { Atom } from './Atom.js';
 import * as AtomToken from './AtomToken.js';
+import { Mp4ContentError } from './AtomToken.js';
 import { type AnyTagValue, type IChapter, type ITrackInfo, TrackType } from '../type.js';
 
 import type { IGetToken } from '@tokenizer/token';
 import { uint8ArrayToHex, uint8ArrayToString } from 'uint8array-extras';
-import { Mp4ContentError } from './AtomToken.js';
 
 const debug = initDebug('music-metadata:parser:MP4');
 const tagFormat = 'iTunes';
@@ -545,14 +545,16 @@ export class MP4Parser extends BasicParser {
     };
 
     let offset = 0;
-    const version = AtomToken.SoundSampleDescriptionVersion.get(sampleDescription.description, offset);
-    offset += AtomToken.SoundSampleDescriptionVersion.len;
-
-    if (version.version === 0 || version.version === 1) {
-      // Sound Sample Description (Version 0)
-      ssd.description = AtomToken.SoundSampleDescriptionV0.get(sampleDescription.description, offset);
-    } else {
-      debug(`Warning: sound-sample-description ${version} not implemented`);
+    if (sampleDescription.description) {
+      const version = AtomToken.SoundSampleDescriptionVersion.get(sampleDescription.description, offset);
+      offset += AtomToken.SoundSampleDescriptionVersion.len;
+
+      if (version.version === 0 || version.version === 1) {
+        // Sound Sample Description (Version 0)
+        ssd.description = AtomToken.SoundSampleDescriptionV0.get(sampleDescription.description, offset);
+      } else {
+        debug(`Warning: sound-sample-description ${version} not implemented`);
+      }
     }
     return ssd;
   }

diff --git a/test/samples/mp4/frag_bunny.mp4 b/test/samples/mp4/frag_bunny.mp4
diff --git a/test/test-file-mp4.ts b/test/test-file-mp4.ts
@@ -473,4 +473,14 @@ describe('Parse MPEG-4 files with iTunes metadata', () => {
     assert.equal(mm.ratingToStars(common.rating[0].rating), 4, 'Vorbis tag rating conversion');
   });
 
+  it('\'stsd\' atom: Handle empty sample entry description', async () => {
+
+    const filePath = path.join(mp4Samples, 'frag_bunny.mp4');
+    const {format, common} = await mm.parseFile(filePath);
+
+    assert.strictEqual(format.container, 'mp42/avc1/iso5', 'format.container');
+    assert.strictEqual(format.codec, 'MPEG-4/AAC', 'format.codec');
+    assert.strictEqual(common.title, undefined, 'common.title');
+  });
+
 });