Detailed Instructions: Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
Q: MPEG-4 Part 14 is an instance of the more general ISO/IEC 14496-12:2004 (MPEG-4 Part 12: ISO base media file format) which is directly based upon the QuickTime File Format.
A:
Which is the basis of MPEG-4 Part 14?