Digital broadcast sending apparatus, receiving apparatus and digital broadcast system

摘要

In the digital broadcast to a mobile unit, the continuous reproduction of an image cannot be guaranteed when switching the hierarchical level in accordance with the receiving condition of the radio wave and therefore the viewer has a sense of discomfort. A digital broadcast sending apparatus sends out by encoding a plurality of simultaneous broadcast streams in the same sync signal generator. A switching determination unit of the receiving apparatus switches the plurality of simultaneous broadcast streams in accordance with the receiving condition (weak hierarchical level/strong hierarchical level), and a sync adjustment unit continuously displays an image without interruptions based on the received sync signal. At the time of this switching operation, one stream is gradually switched to the other.