Quality-based approach to locking multimedia objects

It is critical for applications to obtain enough quality of service (QoS) from multimedia objects. Not only states but also QoS of objects are changed if methods are performed on the objects. The objects are required to be consistent in the presence of multiple transactions issuing requests to the objects. We discuss new types of equivalent and conflicting relations among methods with respect to QoS. We introduce novel types of locking modes, to synchronize concurrent accesses to objects based on the conflicting relations. We also discuss how to convert the lock modes.