That changed when Apple added it as an option in the iPhone 4. (Previous iPhones lacked the oomph to crunch relevant data quickly enough to be practical.) Other examples include cameras and apps that stitch together panoramas from overlapping images shot in an arc around a single point or as a moving sequence.
Rather, it is multiple copies of overlapping fragments, with each fragment also carrying some indexing details that identify where in the overall sequence it should sit.