Cross-cultural comparison of interactive streaming services: Evidence from Twitch

A cross-cultural study of interactive live streaming platforms was conducted to investigate emotional differences in communication behavior. We collected 10,432,423 chat messages from Twitch streams, and our analysis was twofold: (1) classifying viewers by their consumption behavior and (2) analyzing subscribers’ emote usage and emotional expressions. The results showed that there are significant differences in several linguistic and psychological dimensions of emotional expressions between Western and Eastern cultures. Along with these cultural differences, our study addresses the importance of encouraging the social interaction in Twitch for viewer engagement.     

Determinants of live streamers’ continuance broadcasting intentions on Twitch: A self-determination theory perspective

Empowered by today’s rich tools for a media generation, the rapid development of the Internet, and collaborative production, live streaming services that allow anyone to launch a stream or watch someone else perform over the Internet have gained great popularity. This study endeavored to ascertain the determinants compelling live streamers to continue broadcasting on Twitch, a live streaming video platform. This novel research model used self-determination theory to investigate different motivational forces (i.e., intrinsic and extrinsic) that drive live streamers’ continuance broadcasting intentions. Both intrinsic and extrinsic motivation significantly influenced live streamers’ performance expectancies, but not their perceived website attractiveness. Efforts to influence perceived website attractiveness must be made via performance expectancies. Performance expectancy and perceived website attractiveness subsequently affect streamers’ continuance of broadcasting intentions on Twitch. This study yields important managerial implications for live streaming platforms to improve their service design and understanding of streamers’ behavioral intentions.     

A Bayesian approach for user aware peer-to-peer video streaming systems

Peer-to-Peer (P2P) architectures for live video streaming has attracted a significant attention from both academia and industry. P2P design enables end-hosts to relay streams to each other overcoming the scalability issue of centralized architectures. However, these systems struggle to provide a service of comparable quality to that of traditional television. Since end-hosts are controlled by users, their behavior has a strong impact on the performance of P2P streaming systems, leading to potential service disruption and low streaming quality. Thus, considering the user behavior in these systems could bring significant performance improvements. Toward this end, we propose a Bayesian network that captures all the elements making part of the user behavior or related to it. This network is built from the information found in a cross-analysis of numerous large-scale measurement campaigns, analyzing the user behavior in video streaming systems. We validate our model through intensive simulations showing that our model can learn a user behavior and is able to predict several activities helping thus in optimizing these systems for a better performance. We also propose a method based on traces collection of the same user type that accelerates the learning process of this network. Furthermore, we evaluate the performance of this model through exploring its applications and comparison with non-contextual models.     

Experimental Analysis and Evaluation of RaptorQ Codes for Video Multicasting Over Wi-Fi

This paper presents a reliable and efficient high quality video streaming solution for use in challenging outdoor environments over Wi-Fi. An application layer forward error correction based on RaptorQ codes was implemented in a practical Wi-Fi based server and client system to enhance reliability. Thus, this paper presents the first detailed analysis on the implementation of RaptorQ codes for streaming high definition video over Wi-Fi. The measurements were performed in central Bristol with parameters such as RaptorQ symbol size, code rate, buffering time and modulation and coding scheme, and user quality of experience based on these parameters was evaluated. For multicast live video streaming it is demonstrated that system performance is mostly dominated by hardware and software limitations on constrained host platforms where the incoming packet rate exceeds the device`s ability to consume the traffic, i.e., Wi-Fi clients are a major source of packet loss, even in ideal channel conditions. Client limitations were found to be a function of modulation and coding schemes and RaptorQ coding parameters. Therefore, the optimum system design parameters such as RaptorQ symbol size, code rate and buffering time with respect to modulation and coding schemes were suggested considering practical limitations from real-world measurements.

     

Visual‐Attention‐Aware Progressive RoI Trick Mode Streaming in Interactive Panoramic Video Service

In the near future, traditional narrow and fixed viewpoint video services will be replaced by high‐quality panorama video services. This paper proposes a visual‐attention‐aware progressive region of interest (RoI) trick mode streaming service (VA‐PRTS) that prioritizes video data to transmit according to the visual attention and transmits prioritized video data progressively. VA‐PRTS enables the receiver to speed up the time to display without degrading the perceptual quality. For the proposed VA‐PRTS, this paper defines a cutoff visual attention metric algorithm to determine the quality of the encoded video slice based on the capability of visual attention and the progressive streaming method based on the priority of RoI video data. Compared to conventional methods, VA‐PRTS increases the bitrate saving by over 57% and decreases the interactive delay by over 66%, while maintaining a level of perceptual video quality. The experiment results show that the proposed VA‐PRTS improves the quality of the viewer experience for interactive panoramic video streaming services. The development results show that the VA‐PRTS has highly practical real‐field feasibility.     

利用3G手机的实时视频新闻直播系统

提出了基于3G智能手机实现视频远程直播系统的方案。方案利用手机的视频拍摄和数据传输功能,实现视频数据的实时传输,并通过电视播出系统和网络流媒体服务器,进行现场直播。最后,给出了方案的实际实现和测试结果。     

Large-scale personalized video streaming with program insertion proxies

Increasingly intelligent Internet overlay networks promise to deliver streaming media and value-added media services in ways that cannot be achieved easily with conventional broadcast networks. Such an overlay would allow an individual viewer or groups of viewers to receive unique programming content (e.g., commercial advertisements, entertainment) that matches their previously specified preferences. Toward this end, we introduce a scalable overlay network architecture and signaling mechanism that permits dynamic program insertions in live high-quality video streams transmitted over IP networks. We describe the implementation of an application proxy that dynamically inserts prerecorded video programs into NTSC Dl quality motion-JPEG streams with no visible artifacts. We argue that on-demand program switching is merely a first step toward a new generation of media services; increases in computing power ultimately permits network-based proxies to manipulate and augment multimedia content as it flows through the network.     

流媒体直播服务器的设计和实现

以主要函数的描述为中心,以主要函数的流程为线索,通过编写管理员界面及子对话框来实现管理及设置服务器功能,实现符合MPEG4标准的音视频数据。分析了流媒体直播服务器的功能需求,利用MPEG4IP编码库实现MPEG4的软编码,设计了流媒体直播服务器的功能。实验显示,采用SDL技术实现了在Linux平台显示播放,基于RTP/RTSP协议实现了音视频数据的传输,效果良好。     

Peer-to-peer live video streaming on the internet: issues, existing approaches, and challenges [Peer-to-Peer Multimedia Streaming]

Live video streaming is perhaps the greatest unfulfilled promise of the Internet. There have been tremendous efforts in the design and experimentation of video-streaming systems in the past two decades; there have been no shortage of technical innovations, yet no single system has delivered the scale and service quality. The fundamental problem that throttles the large-scale deployment of Internet video streaming is the dissatisfaction end-users experience with performance. This is caused by a combination of many factors, such as the autonomous nature of the Internet, inherent instability, and lack of a service guarantee. This is further challenged by sustainable bandwidth and the stringent continuity requirements of streaming applications. Recent development of P2P-based streaming technology brings unprecedented new momentum to Internet video streaming, which has been shown to be cost-effective, scalable, and easy to deploy. This article reviews the state-of-the-art P2P live video-streaming technologies and their development from a historic perspective. Based on our earlier success with a large-scale P2P streaming system, Coolstreaming, we summarize the main innovations and discuss the key trade offs in the system design. We present our observations on the future development and offer a few insights for further discussion.     

基于IIS平滑流式处理的移动流媒体系统

针对当前流媒体传输协议在无线网络中的不足,采用IIS平滑流式处理技术设计了基于服务器/客户端模式的移动流媒体系统。详细讨地论了微软的IIS平滑流式处理协议,采用该协议传输音/视频数据,搭建了基于IIS7 Web服务器的流媒体服务,设计了一款基于Windows Phone 7智能手机的流媒体播放器客户端。通过在WiFi网络环境下测试该系统,在直播和点播两种播放模式下,客户端播放的视频画面清晰流畅。通过仿真无线网络带宽的变化,验证了IIS平滑流式处理根据客户端的可用带宽实时调整传送到客户端视频流的质量的特性。     

Wireless video streaming with TCP and simultaneous MAC packet transmission (SMPT)

Video streaming is expected to account for a large portion of the traffic in future networks, including wireless networks. It is widely accepted that the user datagram protocol (UDP) is the preferred transport protocol for video streaming and that the transmission control protocol (TCP) is unsuitable for streaming. The widespread use of UDP, however, has a number of drawbacks, such as unfairness and possible congestion collapse, which are avoided by TCP. In this paper we investigate the use of TCP as the transport layer protocol for streaming video in a multi‐code CDMA cellular wireless system. Our approach is to stabilize the TCP throughput over the wireless links by employing a recently developed simultaneous MAC packet transmission (SMPT) approach at the link layer. We study the capacity, i.e. the number of customers per cell, and the quality of service for streaming video in the uplink direction. Our extensive simulations indicate that streaming over TCP in conjunction with SMPT gives good performance for video encoded in a closed loop, i.e. with rate control. We have also found that TCP is unsuitable (even in conjunction with SMPT) for streaming the more variable open‐loop encoded video. Copyright © 2004 John Wiley & Sons, Ltd.     

Video streaming over P2P networks: Challenges and opportunities

A robust real-time video communication service over the Internet in a distributed manner is an important challenge, as it influences not only the current Internet structure but also the future Internet evolution. In this context, Peer-to-Peer (P2P) networks are playing an imperative position for providing efficient video transmission over the Internet. Recently, several P2P video transmission systems have been proposed for live video streaming services or video-on-demand services over the Internet. In this paper, we describe and discuss existing video streaming systems over P2P. Efficient (delay tolerant and intolerant) data sharing mechanisms in P2P and current video coding trends are elaborated in detail. Moreover, video streaming solutions (live and on-demand) over P2P from the perspective of tree-based and mesh-based systems are explained. Finally, the conclusion is drawn with key challenges and open issues related to video streaming over P2P.     

A web-based system for home monitoring of patients with Parkinson's disease using wearable sensors

This letter introduces MercuryLive, a platform to enable home monitoring of patients with Parkinson's disease (PD) using wearable sensors. MercuryLive contains three tiers: a resource-aware data collection engine that relies upon wearable sensors, web services for live streaming and storage of sensor data, and a web-based graphical user interface client with video conferencing capability. Besides, the platform has the capability of analyzing sensor (i.e., accelerometer) data to reliably estimate clinical scores capturing the severity of tremor, bradykinesia, and dyskinesia. Testing results showed an average data latency of less than 400 ms and video latency of about 200 ms with video frame rate of about 13 frames/s when 800 kb/s of bandwidth were available and we used a 40% video compression, and data feature upload requiring 1 min of extra time following a 10 min interactive session. These results indicate that the proposed platform is suitable to monitor patients with PD to facilitate the titration of medications in the late stages of the disease.     

A traffic-camera assisted cache-and-relay routing for live video stream delivery in vehicular ad hoc networks

With the development of the Internet of Things, installation of smart mobile terminal in vehicle has become more and more popular, and consequently, how to provide services for the public utilizing vehicular ad hoc networks has aroused great interest in research and industrial areas. Among them, the kind of services supported by live video streaming attracts more attention because of its advantages. However, due to the high vehicular speed, frequent disconnection and dynamic topology, it’s difficult to guarantee the low-delay delivery of real-time video data, and there is hardly any scheme that can deliver such kind of data with satisfied quality. In this paper, we take fully advantage of the existing wireless enabled traffic cameras, and propose a novel traffic-camera assisted routing for video delivery, which can deliver live video stream to mobile target vehicle with minimal start-up delay while satisfying the required visual quality and playback performance through optimal buffering points selection and intelligent relay among them. The trace-driven simulations demonstrate that our strategy outperforms existing solutions greatly.     

Game of protocols: Is QUIC ready for prime time streaming?

Quick User Datagram Protocol (UDP) Internet Connections (QUIC) is an experimental and low‐latency transport protocol proposed by Google, which is still being improved and specified in the Internet Engineering Task Force (IETF). The viewer's quality of experience (QoE) in HTTP adaptive streaming (HAS) applications may be improved with the help of QUIC's low‐latency, improved congestion control, and multiplexing features. We measured the streaming performance of QUIC on wireless and cellular networks in order to understand whether the problems that occur when running HTTP over TCP can be reduced by using HTTP over QUIC. The performance of QUIC was tested in the presence of network interface changes caused by the mobility of the viewer. We observed that QUIC resulted in quicker start of media streams, better streaming, and seeking experience, especially during the higher levels of congestion in the network and had a better performance than TCP when the viewer was mobile and switched between the wireless networks. Furthermore, we measured QUIC's performance in an emulated network that had a various amount of losses and delays to evaluate how QUIC's multiplexing feature would be beneficial for HAS applications. We compared the performance of HAS applications using multiplexing video streams with HTTP/1.1 over multiple TCP connections to HTTP/2 over one TCP connection and to QUIC over one UDP connection. To that effect, we observed that QUIC provided better performance than TCP on a network that had large delays. However, QUIC did not provide a significant improvement when the loss rate was large. Finally, we analyzed the performance of the congestion control mechanisms implemented by QUIC and TCP, and tested their ability to provide fairness among streaming clients. We found that QUIC always provided fairness among QUIC flows, but was not always fair to TCP.     

Dynamic bitrate allocation of interactive real-time streamed multi-view video with view-switch prediction

In multi-view video (MVV), the real-world scene is usually captured by more than two cameras positioned in an array. A viewer can consume MVV using either a non-interactive or an interactive transmission method. In the context of interactive MVV streaming, view switching may cause a long delay due to the frequent requests by the viewer. In this paper, we consider the use case of real-time interactive MVV (IMVV) streaming, where the view switching delay problem has a significant user experience impact. Our proposed method compress and send all the captured views using a dynamic bitrate allocation method. Also, a novel prediction algorithm has been used to choose possible views that the user might switch to. The predicted view switching is mapped to a hidden Markov model, and the transition probability is solved using Zipf distribution. The experimental results of the proposed method show a superior performance on an objective metric and view-switching delay for better viewing quality over the existing method.     

P2P流媒体技术及其在网络教育中的应用研究

P2P(peer to peer)网络是互联网资源共享的理想途径,为了解决流媒体与带宽之间的矛盾,提出将P2P技术应用于流媒体传输。在流媒体中融入P2P技术,用户可以突破当前网络带宽瓶颈并提高节目播放质量。在此基础上,给出了一个具体的P2P流媒体直播系统的实例。构建了满足现代网络教育的P2P流媒体实现平台,重点叙述基于此平台的网络教育系统基本结构和解决方案,使系统可以满足高质量的教学视频直播。     

A real-time video quality estimator for emerging wireless multimedia systems

Wireless Mesh Networks (WMNs) are increasingly deployed to enable thousands of users to share, create, and access live video streaming with different characteristics and content, such as video surveillance and football matches. In this context, there is a need for new mechanisms for assessing the quality level of videos because operators are seeking to control their delivery process and optimize their network resources, while increasing the user’s satisfaction. However, the development of in-service and non-intrusive Quality of Experience assessment schemes for real-time Internet videos with different complexity and motion levels, Group of Picture lengths, and characteristics, remains a significant challenge. To address this issue, this article proposes a non-intrusive parametric real-time video quality estimator, called MultiQoE that correlates wireless networks’ impairments, videos’ characteristics, and users’ perception into a predicted Mean Opinion Score. An instance of MultiQoE was implemented in WMNs and performance evaluation results demonstrate the efficiency and accuracy of MultiQoE in predicting the user’s perception of live video streaming services when compared to subjective, objective, and well-known parametric solutions.     

基于P2P网络流媒体直播系统研究与设计

主要讨论了一种基于P2P网络的流媒体直播的相关技术,研究设计了一个支持大量用户同时在线的直播系统方案,能够充分利用客户端资源,减轻服务器负载,并实现较好的视频直播效果,该系统采用了P2P传输技术,系统的可扩展性和稳定性都明显优于传统流媒体视频传输系统.