8,171 research outputs found
BOLA360: Near-optimal View and Bitrate Adaptation for 360-degree Video Streaming
Recent advances in omnidirectional cameras and AR/VR headsets have spurred
the adoption of 360-degree videos that are widely believed to be the future of
online video streaming. 360-degree videos allow users to wear a head-mounted
display (HMD) and experience the video as if they are physically present in the
scene. Streaming high-quality 360-degree videos at scale is an unsolved problem
that is more challenging than traditional (2D) video delivery. The data rate
required to stream 360-degree videos is an order of magnitude more than
traditional videos. Further, the penalty for rebuffering events where the video
freezes or displays a blank screen is more severe as it may cause
cybersickness. We propose an online adaptive bitrate (ABR) algorithm for
360-degree videos called BOLA360 that runs inside the client's video player and
orchestrates the download of video segments from the server so as to maximize
the quality-of-experience (QoE) of the user. BOLA360 conserves bandwidth by
downloading only those video segments that are likely to fall within the
field-of-view (FOV) of the user. In addition, BOLA360 continually adapts the
bitrate of the downloaded video segments so as to enable a smooth playback
without rebuffering. We prove that BOLA360 is near-optimal with respect to an
optimal offline algorithm that maximizes QoE. Further, we evaluate BOLA360 on a
wide range of network and user head movement profiles and show that it provides
to more QoE than state-of-the-art algorithms. While ABR
algorithms for traditional (2D) videos have been well-studied over the last
decade, our work is the first ABR algorithm for 360-degree videos with both
theoretical and empirical guarantees on its performance.Comment: 25 page
Streaming and User Behaviour in Omnidirectional Videos
Omnidirectional videos (ODVs) have gone beyond the passive paradigm of traditional video,
offering higher degrees of immersion and interaction. The revolutionary novelty of this technology is the possibility for users to interact with the surrounding environment, and to feel a
sense of engagement and presence in a virtual space. Users are clearly the main driving force of
immersive applications and consequentially the services need to be properly tailored to them.
In this context, this chapter highlights the importance of the new role of users in ODV streaming applications, and thus the need for understanding their behaviour while navigating within
ODVs. A comprehensive overview of the research efforts aimed at advancing ODV streaming
systems is also presented. In particular, the state-of-the-art solutions under examination in this
chapter are distinguished in terms of system-centric and user-centric streaming approaches: the
former approach comes from a quite straightforward extension of well-established solutions for
the 2D video pipeline while the latter one takes the benefit of understanding users’ behaviour
and enable more personalised ODV streaming
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