DASH fast start using HTTP/2

Proceedings of the 25th ACM International Conference on Multimedia

Hosseini

et al. 2017

138

Virtual Reality (VR) devices are becoming accessible to a large public, which is going to increase the demand for 360°VR videos. VR videos are often characterized by a poor quality of experience, due to the high bandwidth required to stream the 360°video. To overcome this issue, we spatially divide the VR video into tiles, so that each temporal segment is composed of several spatial tiles. Only the tiles belonging to the viewport, the region of the video watched by the user, are streamed at the highest quality. The other tiles are instead streamed at a lower quality. We also propose an algorithm to predict the future viewport position and minimize quality transitions during viewport changes. The video is delivered using the server push feature of the HTTP/2 protocol. Instead of retrieving each tile individually, the client issues a single push request to the server, so that all the required tiles are automatically pushed back to back. This approach allows to increase the achieved throughput, especially in mobile, high RTT networks. In this paper, we detail the proposed framework and present a prototype developed to test its performance using real-world 4G bandwidth traces. Particularly, our approach can save bandwidth up to 35% without severely impacting the quality viewed by the user, when compared to a traditional non-tiled VR streaming solution. Moreover, in high RTT conditions, our HTTP/2 approach can reach 3 times the throughput of tiled streaming over HTTP/1.1, and consistently reduce freeze time. These results represent a major improvement for the e cient delivery of 360°VR videos over the Internet.

Section: Http/2-based Adaptive Streamingmentioning

confidence: 99%

An HTTP/2-Based Adaptive Streaming Framework for 360° Virtual Reality Videos

Petrangeli

Proceedings of the 25th ACM International Conference on Multimedia

Hosseini

et al. 2017

138

“…The k-push has also been extended to optimize the battery lifetime on mobile devices [13]. Cherif et al use server push and WebSocket to reduce the startup delay in a DASH streaming session [2]. In this work, we exploit the server push functionality to reduce the network overhead introduced by spatially tiling the video.…”

Section: Http/2-based Adaptive Streamingmentioning

confidence: 99%

Improving Virtual Reality Streaming using HTTP/2

Petrangeli

Proceedings of the 8th ACM on Multimedia Systems Conference

Hosseini

et al. 2017

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.

“…One major strategy in this work is to adopt full-push while additional messages are used to control the video quality adapta- tion. Wael Cherif et al [2] also investigated the push mechanism for fast start in the DASH-compliant video streaming.…”

Section: Server Push-based Streamingmentioning

confidence: 99%

Evaluating and improving push based video streaming with HTTP/2

Xiao

Proceedings of the 26th International Workshop on Network and Operating Systems Support for Digital Audio and Video

Wei

et al. 2016

The sever-initiated push mechanism is one of the most prominent features in the next generation HTTP/2 protocol, having shown its capability on saving network traffic and improving the web page retrieval latency. Our prior work has investigated the server pushbased mechanism for HTTP video streaming and proposed a kpush scheme, where the server pushes k video segments following the response to a request. In this study, we further conduct an analysis and evaluation of the k-push scheme in HTTP streaming. Our results uncover that the push mechanism can efficiently increase the network utilization (under certain conditions) compared to regular HTTP streaming. However the results also show that the k-push scheme deteriorates network adaptability and leads to the "over-push" problem, in which the pushed video content waste network resources due to user abandonment behaviors. To overcome these limitations, we propose a new " adaptive-push" scheme, which dynamically adjusts the parameter k to adapt to the runtime environment. To evaluate the performance of adaptivepush, we implemented a prototype system. The experimental results show that compared to k-push, adaptive-push can improve the network adaptability. Furthermore, our real-world trace based simulation results show that adaptive-push can effectively alleviate the over-push problem.