A multi-level coding awareness model combined with network QoS on bitmap-based graphic collaborative editing system

Workspace awareness is one of the key issues in real-time collaborative editing systems, especially in bitmap-based graphic editing system. Because of the intrinsic characteristics of bitmap, the data stream that needs to be exchanged in the network increases dramatically. On the other hand, the different collaborators in one collaborative project may have different network environments. It is therefore irrational to deliver the same large data-stream to distinct receivers. We propose a multi-level coding method which encodes each bitmap operation into several different granularities. We also propose a self-adapted awareness model by combining the awareness model with network QoS. As a result, different collaborators receive different data-streams in different granularity.