New Journal Paper: A Client-based Adaptation Framework for 360-degree Video Streaming

In our latest work, a new client-based adaptation framework for 360-degree video streaming is proposed. Our framework can support different application scenarios. Especially, we introduce for the first time the use of bitrate and quality estimation in viewport adaptive streaming of 360 videos. The key findings from our work are as follows.

• The use of estimated bitrate/quality improves the viewport quality significantly 
• The proposed method performs as if knowing full information of bitrate/quality 
• The proposed method can be applied to both Equirectangular and Cubemap projections 
• Cube performs slightly better than Equirectangular 
• Long client buffering could have severe impacts on the visual quality in VR

You can find the full paper of our work here.

What is 360-degree video?

360-degree video is one of the key element of Virtual Reality. A 360-degree video captures 360-degree view of a scene. Thus, different from conventional videos, you can freely change your viewing direction while watching 360 videos. This provides the so-called "immersive experience" to the user. You can try 360 videos at YouTube Virtual Reality channel (link). 360 video is being used in a wide range of applications such as gaming, advertising, training, e-learning.

High bitrate: the key challenge of 360 video streaming

To cover the full 360-degree view, 360 video has much higher resolution than conventional videos (at least 6 times). Moreover, 360 video is usually watched on Head-Mounted Display (e.g., Occulus Rift) where the display is much closer to your eyes than in the cases of viewing on TVs or computer. For satisfactory user viewing experience, 360 video should have a resolution of 4K or higher, results in very high bitrate.

Viewport Adaptive Streaming

To cope with the high bitrate of 360 video, Viewport Adaptive Streaming (VAS) has been proposed. The basic idea is to deliver the video parts visible to the user at a high quality while delivering the remaining video parts at a lower quality. VAS can be realized using tiling-based approach or viewport-dependent coding approach.