Recurse m4a atoms to search for ilst

mutagen/mp4/__init__.py

@@ -340,17 +340,27 @@ def __init__(self, *args, **kwargs):
  if args or kwargs:
  self.load(*args, **kwargs)
 
- def load(self, atoms, fileobj):
- try:
- path = atoms.path(b"moov", b"udta", b"meta", b"ilst")
- except KeyError as key:
- raise MP4MetadataError(key)
-
- free = _find_padding(path)
- self._padding = free.datalength if free is not None else 0
+ def load(self, atoms: Atoms, fileobj):
+ for atom in atoms.atoms:
+ if atom.children is not None:
+ self._recurse_atom(atom, fileobj)
+
+ def _recurse_atom(self, parent: Atom, fileobj):
+ """Recursively search for an ilst atom to read metadata from.
+
+ Recursing helps if the mp4/m4a container didn't store metadata correctly,
+ which is usually expected at moov.udta.meta.ilst"""
+ if parent.name != b"ilst":
+ for atom in parent.children:
+ if parent.name == b"meta" and atom.name == b"ilst":
+ free = _find_padding([parent, atom])
+ self._padding = free.datalength if free is not None else 0
+
+ if atom.children is not None and atom.name != 'ilst':
+ self._recurse_atom(atom, fileobj)
+ return
 
- ilst = path[-1]
- for atom in ilst.children:
+ for atom in parent.children:
  ok, data = atom.read(fileobj)
  if not ok:
  raise MP4MetadataError("Not enough data")