In synchronization of a conventional AV system, when a stream as the
master stops, a system clock cannot be corrected for synchronization.
Since the correction is consistently performed even when an error is
small, overhead of correction is large. On the other hand, when an error
is large, sharp correction causes a feeling that something wrong. In the
present invention, when the stream as the master stops, previously
registering the degree of priority regarding the master, consideration of
a corrected period or a previous error for the system clock, or
transmitting a stream containing information regarding the master can
allow for other process to serves as the master. Accordingly, it is
possible to provide a method for synchronization with maintaining
correction of the system clock. When a corrected error is large, gradual
correction or reference can provide a system with normal feeling.
Furthermore, when an error of correction is small, omission of correction
or reference can provide a system with less overhead.