Improving Virtual Reality Streaming using HTTP/2
Improving Virtual Reality Streaming using HTTP/2
复制标题
使用 HTTP/2 改进虚拟现实流
DOI：
10.1145/3083187.3083224
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Mohammad Hosseini
中科院分区：
文献类型：
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作者：
Stefano Petrangeli;F. Turck;Viswanathan Swaminathan;Mohammad Hosseini
由于VR头显的普及，对360°虚拟现实（VR）视频的需求预计将在不久的将来增长。然而，VR流媒体受到360°视频高带宽要求的挑战。为了节省带宽，我们使用H.265标准对视频进行空间平铺，并仅以最高质量流式传输。视频也是时间分段的，因此每个时间段由几个空间块组成。为了最大限度地减少用户移动时的质量转换，开发了一种算法来预测用户在不久的将来可能会观看的内容。因此，预测的瓷砖也以最高的质量流式传输。最后，使用HTTP/2中的服务器推送来传送贴片视频。客户端只发送一个请求；段的所有磁贴都自动从服务器推送。与传统的HTTP/1.1上的流媒体相比，这种方法带来了更好的带宽利用率和视频质量，在传统的HTTP/1.1上，每个tile都必须由客户端独立请求。我们使用在三星Galaxy S7和Gear VR上开发的原型来展示我们框架的好处，它支持平铺和非平铺视频以及HTTP/1.1和HTTP/2上的流媒体。在有限的带宽条件下，我们演示了我们的框架如何提高用户观看的质量，而不是以相同质量流式传输所有视频的非平铺解决方案。这一结果代表了VR视频高效流媒体的重大改进。
The demand for 360° Virtual Reality (VR) videos is expected to grow in the near future, thanks to the diffusion of VR headsets. VR Streaming is however challenged by the high bandwidth requirements of 360° videos. To save bandwidth, we spatially tile the video using the H.265 standard and stream only tiles in view at the highest quality. The video is also temporally segmented, so that each temporal segment is composed of several spatial tiles. In order to minimize quality transitions when the user moves, an algorithm is developed to predict where the user is likely going to watch in the near future. Consequently, predicted tiles are also streamed at the highest quality. Finally, the server push in HTTP/2 is used to deliver the tiled video. Only one request is sent from the client; all the tiles of a segment are automatically pushed from the server. This approach results in a better bandwidth utilization and video quality compared to traditional streaming over HTTP/1.1, where each tile has to be requested independently by the client. We showcase the benefits of our framework using a prototype developed on a Samsung Galaxy S7 and a Gear VR, which supports both tiled and non-tiled videos and streaming over HTTP/1.1 and HTTP/2. Under limited bandwidth conditions, we demonstrate how our framework can improve the quality watched by the user compared to a non-tiled solution where all of the video is streamed at the same quality. This result represents a major improvement for the efficient streaming of VR videos.