fix: check for multiple id3 sections in a file (#21)

videojs · Oct 6, 2020 · 759a039 · 759a039
1 parent 9983be8
commit 759a039
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Showing 2 changed files with 43 additions and 9 deletions.
diff --git a/src/containers.js b/src/containers.js
@@ -1,24 +1,37 @@
 import {bytesToString, toUint8} from './byte-helpers.js';
 
-export const getId3Offset = function(bytes) {
+export const id3Size = function(bytes, offset = 0) {
  bytes = toUint8(bytes);
 
- if (bytes.length < 10 || bytesToString(bytes.subarray(0, 3)) !== 'ID3') {
- return 0;
- }
- const returnSize = (bytes[6] << 21) |
- (bytes[7] << 14) |
- (bytes[8] << 7) |
- (bytes[9]);
- const flags = bytes[5];
+ const returnSize = (bytes[offset + 6] << 21) |
+ (bytes[offset + 7] << 14) |
+ (bytes[offset + 8] << 7) |
+ (bytes[offset + 9]);
+ const flags = bytes[offset + 5];
  const footerPresent = (flags & 16) >> 4;
 
  if (footerPresent) {
  return returnSize + 20;
  }
+
  return returnSize + 10;
 };
 
+export const getId3Offset = function(bytes, offset = 0) {
+ bytes = toUint8(bytes);
+
+ if ((bytes.length - offset) < 10 || bytesToString(bytes.subarray(offset, offset + 3)) !== 'ID3') {
+ return offset;
+ }
+
+ offset += id3Size(bytes, offset);
+
+ // recursive check for id3 tags as some files
+ // have multiple ID3 tag sections even though
+ // they should not.
+ return getId3Offset(bytes, offset);
+};
+
 export const isLikely = {
  aac(bytes) {
  const offset = getId3Offset(bytes);

diff --git a/test/container.test.js b/test/container.test.js
@@ -53,8 +53,29 @@ QUnit.test('should identify known types', function(assert) {
  const dataWithId3 = new Uint8Array([].concat(id3Data).concat(testData[type]));
  const dataWithId3Footer = new Uint8Array([].concat(id3DataWithFooter).concat(testData[type]));
 
+ const recursiveDataWithId3 = new Uint8Array([]
+ .concat(id3Data)
+ .concat(id3Data)
+ .concat(id3Data)
+ .concat(testData[type]));
+ const recursiveDataWithId3Footer = new Uint8Array([]
+ .concat(id3DataWithFooter)
+ .concat(id3DataWithFooter)
+ .concat(id3DataWithFooter)
+ .concat(testData[type]));
+
+ const differentId3Sections = new Uint8Array([]
+ .concat(id3DataWithFooter)
+ .concat(id3Data)
+ .concat(id3DataWithFooter)
+ .concat(id3Data)
+ .concat(testData[type]));
+
  assert.equal(detectContainerForBytes(dataWithId3), type, `id3 skipped and ${type} detected`);
  assert.equal(detectContainerForBytes(dataWithId3Footer), type, `id3 + footer skipped and ${type} detected`);
+ assert.equal(detectContainerForBytes(recursiveDataWithId3), type, `id3 x3 skipped and ${type} detected`);
+ assert.equal(detectContainerForBytes(recursiveDataWithId3Footer), type, `id3 + footer x3 skipped and ${type} detected`);
+ assert.equal(detectContainerForBytes(differentId3Sections), type, `id3 with/without footer skipped and ${type} detected`);
  });
 
  const notTs = []