Multimedia operating systems must have real-time features and other supporting features in order to meet the QoS requirements of distributed multimedia applications. It is not enough to simply give communication processing activities higher priorities, it is necessary to realize a soft real-time framework which controls all system activities. In addition, feasible soft real-time scheduling schemes are the cornerstones for the functionality and efficiency of the framework. In the paper, the motivation, rationale and realization schemes of our framework proposal are addressed. We have also proposed and are experimenting with several base scheduling methods which are suitable for supporting continuous media communications and applications. These include a cooperative soft real-time scheduling method (CO-SCHEDULE) and a semi-imperative soft real-time scheduling method (SIM-SCHEDULE). The design and implementation structure of these scheduling methods are described. Preliminary implementation experiences are also presented.