Real-time scheduling on scalable media stream delivery

Scalable streams provide a layered representation for transmitting media contents over a channel with packet losses and variable delay. In general, real-time streaming scalable media to audience has timing constraints, and different layers in a frame have different importance to the playback quality reconstructed in client. In this paper, we proposes an efficient and simple real-time scheduling algorithm, Layer-Based Earliest Deadline First (LB-EDF) algorithm, which decides how to transmit/re-transmit video packets at any given time for delivery of scalable streaming media over a lossy channel. Besides real-time constraint, unequal priorities of scalable source bitstream in different layers are taken into account in the proposed algorithm. This guarantees the better usage of available bandwidth and the smoother playback. Simulated results show that, with the proposed approach, the playback quality has a greatly improvement.