While a standard MPEG file already consists of interleaved streams, in ILVU the streams are divided into portions that are shared between titles and those that are unique to one title. These are then divided into smaller segments that are interleaved with each other. If you look at the diagram below you can see that additional video, or video audio, and subpicture segments are inserted between the original interleaved segments. This ensures seamless playback as long as the laser doesn't have to move too far across the disc to reach the next segment in a particular Angle or Branch. The size of each segment can also be reduced to keep the distances smaller.
