HYBRID CONTROL-BASED ABR: TOWARDS LOW-DELAY LIVE STREAMING

Video content providers are increasingly interested in interactive live streaming since user engagement increases their revenues. To provide high quality of experience (QoE), it is critical to design a low delay adaptive bitrate (ABR) algorithm, but which is lacked in existing studies. The low delay constraint poses much more challenges to achieve high bitrate and low rebuffering. For example, low delay requires the player to maintain a small playback buffer, which, however, increases the risk of rebuffering. This work designs a low delay ABR algorithm called HCA which provides good QoE by controlling the buffer occupancy at a low but non-empty level. To achieve accurate control, HCA uses the hybrid of feedback and feedforward control to regulate the buffer dynamic (buffer occupancy and its variation) based on predictions of future network condition (throughput and its variation). Trace-driven experiments show that HCA achieves zero rebuffering for 98% of all traces while ensuring high bitrate.