  The main task of HTTP Adaptive Streaming is to adapt video quality
dynamically under variable network conditions. This is a key feature for
multimedia delivery especially when quality of service cannot be granted
network-wide and, e.g., throughput may suffer short term fluctuations.
  Hence, robust bitrate adaptation schemes become crucial in order to improve
video quality. The objective, in this context, is to control the filling level
of the playback buffer and maximize the quality of the video, while avoiding
unnecessary video quality variations.
  In this paper we study bitrate adaptation algorithms based on
Backward-Shifted Coding (BSC), a scalable video coding scheme able to greatly
improve video quality. We design bitrate adaptation algorithms that balance
video rate smoothness and high network capacity utilization, leveraging both on
throughput-based and buffer-based adaptation mechanisms.
  Extensive simulations using synthetic and real-world video traffic traces
show that the proposed scheme performs remarkably well even under challenging
network conditions.
