Many multimedia applications rely on video streaming techniques. However, video delivery over a Best Effort network such as today's Internet is a challenge. Traffic load in the network changes dynamically and in an unpredictable way causing the resource availability to vary. Providing an application level end-to-end quality of service in such an environment requires network-awareness and ability to adapt. We address the issue of mapping between application-level quality of service for streaming video and network-level quality of service. We show that continuous playback requires a limit on the delay jitter. We tackle the problem of providing end-to-end video quality given that the network does not guarantee limited delay variability. Our approach is unique in a way we do not model network as a black box but investigate what information about the network status is necessary for an application to make adaptation decisions. We rely on simple multi-level ECN-based mechanism to obtain a feedback from the network as well as on end-point observations to determine available bandwidth. Such an approach allows to obtain better user-perceived video quality by providing additional information to properly interpret the arrival rate observed at the end-point. We propose a 3-rate adaptation mechanism for video streaming to illustrate the philosophy of adaptivity based on network awareness, where the network awareness is not limited to observing network reaction to a set of stimuli.
Bibliographical noteFunding Information:
This work is partially supported by NSF Grant EIA-0224424.
- Adaptive multimedia
- Network-aware application
- Video streaming