MPEG-4 FGS Video Streaming with Constant-Quality Rate Control and Differentiated Forwarding

摘要

Streaming video over IP is studied by integrating the error resilient scalable source codec with constant quality rate adaptation and prioritized network transmission. The scalable codec is based on the standardized ISO/IEC MPEG-4 fine granular scalable (FGS) coding scheme, which allows arbitrary truncation according to the given rate budget. To maximize the end-to-end visual quality, constant quality video rate control (CQVRC) is proposed to preserve smooth video quality when there is a significant amount of variation in the video source, the available bandwidth or both. The proposed CQVRC attempts to provide smooth video quality for both the base layer (BL) and the enhancement layer (EL). The video stream is then prioritized for priority dropping, where rate adaptation is dynamically performed to meet the time-varying available bandwidth. This kind of prioritized stream can benefit from QoS networks such as the IP differentiated service (DiffServ). All key components, including FGS encoding, CQVRC based rate adaptation and packetization, error resilient decoding, and differentiated forwarding, are seamlessly integrated into one system. By focusing on the end-to-end quality, we set both source and network parameters properly to achieve a superior performance of FGS video streaming.