Traffic models for MPEG-4 spatial scalable video

MPEG-4 spatial scalable encoding scheme (SSES) provides different resolutions and wide range of VBR (variate bit rate) video to satisfy requirements of end users with variant screen resolutions and network bandwidth. In a SSES, one base layer traffic and one (or more) enhancement layer(s) traffic are generated. Although many traffic models have been developed for single layer video traffic, none exists for VBR SSES video traffic. Our extensive studies suggest that MMG (Markov-Modulated Gamma) model can capture base layer traffic quite well. However, it cannot be used for modeling enhancement layer traffic for two reasons: (1) enhancement layers have no I-frames, (2) enhancement layer traffic and base layer traffic are not independent and have a strong correlation. In this paper, we propose two models for enhancement layer traffic and aggregate traffic. To maintain the correlation between base layer and enhancement layers, we augment the base-layer state transition model. The augmentation uses state transition relation between base layer and enhancement layer traffic or between base layer and aggregate traffic. The models have been validated by QQ plots and leaky-bucket simulations. The model generated traffic streams quite accurately mimic original traffic streams.