96 research outputs found

    Network and Content Intelligence for 360 Degree Video Streaming Optimization

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    In recent years, 360° videos, a.k.a. spherical frames, became popular among users creating an immersive streaming experience. Along with the advances in smart- phones and Head Mounted Devices (HMD) technology, many content providers have facilitated to host and stream 360° videos in both on-demand and live stream- ing modes. Therefore, many different applications have already arisen leveraging these immersive videos, especially to give viewers an impression of presence in a digital environment. For example, with 360° videos, now it is possible to connect people in a remote meeting in an interactive way which essentially increases the productivity of the meeting. Also, creating interactive learning materials using 360° videos for students will help deliver the learning outcomes effectively. However, streaming 360° videos is not an easy task due to several reasons. First, 360° video frames are 4–6 times larger than normal video frames to achieve the same quality as a normal video. Therefore, delivering these videos demands higher bandwidth in the network. Second, processing relatively larger frames requires more computational resources at the end devices, particularly for end user devices with limited resources. This will impact not only the delivery of 360° videos but also many other applications running on shared resources. Third, these videos need to be streamed with very low latency requirements due their interactive nature. Inability to satisfy these requirements can result in poor Quality of Experience (QoE) for the user. For example, insufficient bandwidth incurs frequent rebuffer- ing and poor video quality. Also, inadequate computational capacity can cause faster battery draining and unnecessary heating of the device, causing discomfort to the user. Motion or cyber–sickness to the user will be prevalent if there is an unnecessary delay in streaming. These circumstances will hinder providing im- mersive streaming experiences to the much-needed communities, especially those who do not have enough network resources. To address the above challenges, we believe that enhancements to the three main components in video streaming pipeline, server, network and client, are essential. Starting from network, it is beneficial for network providers to identify 360° video flows as early as possible and understand their behaviour in the network to effec- tively allocate sufficient resources for this video delivery without compromising the quality of other services. Content servers, at one end of this streaming pipeline, re- quire efficient 360° video frame processing mechanisms to support adaptive video streaming mechanisms such as ABR (Adaptive Bit Rate) based streaming, VP aware streaming, a streaming paradigm unique to 360° videos that select only part of the larger video frame that fall within the user-visible region, etc. On the other end, the client can be combined with edge-assisted streaming to deliver 360° video content with reduced latency and higher quality. Following the above optimization strategies, in this thesis, first, we propose a mech- anism named 360NorVic to extract 360° video flows from encrypted video traffic and analyze their traffic characteristics. We propose Machine Learning (ML) mod- els to classify 360° and normal videos under different scenarios such as offline, near real-time, VP-aware streaming and Mobile Network Operator (MNO) level stream- ing. Having extracted 360° video traffic traces both in packet and flow level data at higher accuracy, we analyze and understand the differences between 360° and normal video patterns in the encrypted traffic domain that is beneficial for effec- tive resource optimization for enhancing 360° video delivery. Second, we present a WGAN (Wesserstien Generative Adversarial Network) based data generation mechanism (namely VideoTrain++) to synthesize encrypted network video traffic, taking minimal data. Leveraging synthetic data, we show improved performance in 360° video traffic analysis, especially in ML-based classification in 360NorVic. Thirdly, we propose an effective 360° video frame partitioning mechanism (namely VASTile) at the server side to support VP-aware 360° video streaming with dy- namic tiles (or variable tiles) of different sizes and locations on the frame. VASTile takes a visual attention map on the video frames as the input and applies a com- putational geometric approach to generate a non-overlapping tile configuration to cover the video frames adaptive to the visual attention. We present VASTile as a scalable approach for video frame processing at the servers and a method to re- duce bandwidth consumption in network data transmission. Finally, by applying VASTile to the individual user VP at the client side and utilizing cache storage of Multi Access Edge Computing (MEC) servers, we propose OpCASH, a mech- anism to personalize the 360° video streaming with dynamic tiles with the edge assistance. While proposing an ILP based solution to effectively select cached variable tiles from MEC servers that might not be identical to the requested VP tiles by user, but still effectively cover the same VP region, OpCASH maximize the cache utilization and reduce the number of requests to the content servers in congested core network. With this approach, we demonstrate the gain in latency and bandwidth saving and video quality improvement in personalized 360° video streaming

    EFFECT ON 360 DEGREE VIDEO STREAMING WITH CACHING AND WITHOUT CACHING

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    People all around the world are becoming more and more accustomed to watching 360-degree videos, which offer a way to experience virtual reality. While watching videos, it enables users to view video scenes from any perspective. To reduce bandwidth costs and provide the video with less latency, 360-degree video caching at the edge server may be a smart option. A hypothetical 360-degree video streaming system can partition popular video materials into tiles that are cached at the edge server. This study uses the Least Recently Used (LRU) and Least Frequently Used (LFU) algorithms to accomplish video caching and suggest a system architecture for 360-degree video caching. Two 360-degree videos from 48 users\u27 head movements are used in the experiment, and caching between the LRU cache and LFU cache is compared by changing the cache size. The findings demonstrate that, for varied cache sizes, utilizing LFU caching outperforms LRU caching in terms of average cache hit rate. In the first part of the research, we compared LRU and LFU caching algorithm. In the second part of the research, a suitable caching strategy model was developed based on user’s field of view. Field of view (FoV) is the term used to describe the portion of the 3600 videos that viewers typically see when watching 3600 videos. Edge caching can be a smart way to increase customer satisfaction while maximizing bandwidth usage (QoE). A 3600-video caching strategy has been developed in this study using three machine learning models that use random forest, linear regression, and Bayesian regression. As features, tiles\u27 frequency, user\u27s view prediction probability, and resolution were used. The created machine learning models are designed to decide the caching method for 360-degree video tiles. The models can forecast the frequency of viewing for 3600 video tiles (subsets of a full video). With a predictive R2 value of 0.79, the random forest regression model performs better than the other suggested models when the outcomes of the three developed models are compared. In the third part of the research, to compare our machine learning algorithm with LRU algorithm, a python test bench program was written to evaluate both algorithms on the test set by varying the cache size. The results demonstrate that our machine learning approach, which was created for 360-degree video caching, outperforms the LRU algorithm

    Delivery of 360° videos in edge caching assisted wireless cellular networks

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    In recent years, 360° videos have become increasingly popular on commercial social platforms, and are a vital part of emerging Virtual Reality (VR) applications. However, the delivery of 360° videos requires significant bandwidth resources, which makes streaming of such data on mobile networks challenging. The bandwidth required for delivering 360° videos can be reduced by exploiting the fact that users are interested in viewing only a part of the video scene, the requested viewport. As different users may request different viewports, some parts of the 360° scenes may be more popular than others. 360° video delivery on mobile networks can be facilitated by caching popular content at edge servers, and delivering it from there to the users. However, existing edge caching schemes do not take full potential of the unequal popularity of different parts of a video, which renders them inefficient for caching 360° videos. Inspired by the above, in this thesis, we investigate how advanced 360° video coding tools, i.e., encoding into multiple quality layers and tiles, can be utilized to build more efficient wireless edge caching schemes for 360° videos. The above encoding allows the caching of only the parts of the 360° videos that are popular in high quality. To understand how edge caching schemes can benefit from 360° video coding, we compare the caching of 360° videos encoded into multiple quality layers and tiles with layer-agnostic and tile-agnostic schemes. To cope with the fact that the content popularity distribution may be unknown, we use machine learning techniques, for both Video on Demand (VoD), and live streaming scenarios. From our findings, it is clear that by taking into account the aforementioned 360° video characteristics leads to an increased performance in terms of the quality of the video delivered to the users, and the usage of the backhaul links
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