long ContentEncoding::ParseContentEncAESSettingsEntry(
    long long start, long long size, IMkvReader* pReader,
    ContentEncAESSettings* aes) {
  assert(pReader);
  assert(aes);

  long long pos = start;
  const long long stop = start + size;

  while (pos < stop) {
    long long id, size;
    const long status = ParseElementHeader(pReader, pos, stop, id, size);
    if (status < 0)  // error
      return status;

    if (id == libwebm::kMkvAESSettingsCipherMode) {
      aes->cipher_mode = UnserializeUInt(pReader, pos, size);
      if (aes->cipher_mode != 1)
        return E_FILE_FORMAT_INVALID;
    }

    pos += size;  // consume payload
    if (pos > stop)
      return E_FILE_FORMAT_INVALID;
  }

  return 0;
}
Unknown