对于日益发展的移动互联网来说,流媒体是其最重要最有需求和市场的应用之一。本论文以Http Live Streaming技术为背景,详细介绍了Android平台架构和Android NDK开发,并在此基础上介绍并设计了移动流媒体直播系统,实现了无线网络视频的...对于日益发展的移动互联网来说,流媒体是其最重要最有需求和市场的应用之一。本论文以Http Live Streaming技术为背景,详细介绍了Android平台架构和Android NDK开发,并在此基础上介绍并设计了移动流媒体直播系统,实现了无线网络视频的传输。最后,通过性能测试,实现了客户端采集编码功能。展开更多
In this paper, we present an innovative design of multiple description coding with spatial-temporal hybrid interpola- tion (MDC-STHI) for peer-to-peer (P2P) video streaming. MDC can be effective in P2P networks becaus...In this paper, we present an innovative design of multiple description coding with spatial-temporal hybrid interpola- tion (MDC-STHI) for peer-to-peer (P2P) video streaming. MDC can be effective in P2P networks because the nature of overlay routing makes path diversity more feasible. However, most MDC schemes require a redesign of video coding systems and are not cost-effective for wide deployment. We base our work on multiple state video coding, a form of MDC that can utilize standard codecs. Two quarter-sized video bit streams are generated as redundancies and embedded in the original-sized streams. With MDC-STHI, the nodes in P2P network can adjust the streaming traffic to satisfy the constraints of their devices and network environment. By design, the redundancies are used to compensate for missing frames, and can also be streamed independently to fulfill certain needs of low rate, low resolution applications. For better error concealment, optimal weights for spatial and temporal interpolation are determined at the source, quantized, and included in redundancies.展开更多
Multi-channel can be used to provide higher transmission ability to the bandwidth-intensive and delay-sensitive real-time streams. However, traditional channel capacity theories and coding schemes are seldom designed ...Multi-channel can be used to provide higher transmission ability to the bandwidth-intensive and delay-sensitive real-time streams. However, traditional channel capacity theories and coding schemes are seldom designed for the real-time streams with strict delay constraint, especially in multi-channel context. This paper considers a real-time stream system, where real-time messages with different importance should be transmitted through several packet erasure channels, and be decoded by the receiver within a fixed delay. Based on window erasure channels and i.i.d.(identically and independently distributed) erasure channels, we derive the Multi-channel Real-time Stream Transmission(MRST) capacity models for Symmetric Real-time(SR) streams and Asymmetric Real-time(AR) streams respectively. Moreover, for window erasures, a Maximum Equilibrium Intra-session Code(MEIC) is presented for SR and AR streams, and is shown able to asymptotically achieve the theoretical MRST capacity. For i.i.d. erasures, we propose an Adaptive Maximum Equilibrium Intra-session Code(AMEIC), and then prove AMEIC can closely approach the MRST transmission capacity. Finally, the performances of the proposed codes are verified by simulations.展开更多
To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA)...To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks, a cross-layer design framework that jointly selects the Transmission Policy (TP) for SVC video frames, assigns OFDMA subcarriers, and allocates power for each subcarrier is proposed. We apply the dual decomposition method to the problem, and obtain a TP selection subproblem for each SVC video adaptation and a resource allocation subproblem of Joint Subcarrier, Relay and Power Allocation (JSRPA). A second level of dual decomposition is used to divide the JSRPA problem into independent subcarrier subproblems. The proposed Crosslayer Trade-off Optimization (CTO) algorithm is sub-distributed with significantly low complexity. A performance evaluation with typical SVC video traces demonstrates that the proposed algorithm is able to converge and efficiently achieve the optimal trade-off between the video quality and energy consumption at the MSs for uplink SVC streaming.展开更多
Over the past years, we have witnessed an explosive growth in the use of multimedia applications such as audio and video streaming with mobile and static devices. Multimedia streaming applications need new approaches ...Over the past years, we have witnessed an explosive growth in the use of multimedia applications such as audio and video streaming with mobile and static devices. Multimedia streaming applications need new approaches to multimedia transmissions to meet the growing volume demand and quality expectations of multimedia traffic. This paper studies network coding which is a promising paradigm that has the potential to improve the performance of networks for multimedia streaming applications in terms of packet delivery ratio (PDR), latency and jitter. This paper examines several network coding protocols for ad hoc wireless mesh networks and compares their performance on multimedia streaming applications with optimized broadcast protocols, e.g., BCast, Simplified Multicast Forwarding (SMF), and Partial Dominant Pruning (PDP). The results show that the performance increases significantly with the Random Linear Network Coding (RLNC) scheme.展开更多
The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Gover...The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Government Area of Akawa Ibom State in Nigeria were carried out using standard analytical procedures. The parameters investigated were temperature(Temp.), hydrogen ion concentration(pH), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO) and biochemical oxygen demand (BOD). Correlation analysis carried out between pairs of variables showed that only the correlation coefficients between TDS and DO in ANS( p <0.05); Temp. and TDS in IES ( p <0.05) and between Temp. and TDS in AIS ( p <0.01) were significant. None of the pairs of the variables in NDS showed any significant correlation. The coefficients of variation for the parameters were also computed and used in determining their stability in the water. The possible effects of these variables on each other and on the aquatic ecosystem were discussed.展开更多
针对智能交通管理设备本身缺乏安全监管,传统视频监控延迟高、画质低、稳定性差的问题,提出一种基于FFmpeg的多线程编码视频流传输方案。通过FFmpeg调用h264_nvenc编码器,实现宏块行级的GPU多线程加速,降低编码延迟。使用Visual Studio ...针对智能交通管理设备本身缺乏安全监管,传统视频监控延迟高、画质低、稳定性差的问题,提出一种基于FFmpeg的多线程编码视频流传输方案。通过FFmpeg调用h264_nvenc编码器,实现宏块行级的GPU多线程加速,降低编码延迟。使用Visual Studio 2019和QT15.5开发基于FFmpeg的音视频处理软件,对多路视频流进行封装、推流,并搭建Nginx流媒体服务器进行分发。通过实验表明,该系统整体的传输延迟低于1 s,且拥有良好的率失真特性,监控画面清晰、稳定性高,实现了对交通管理设备实时稳定的安全监控。展开更多
文摘对于日益发展的移动互联网来说,流媒体是其最重要最有需求和市场的应用之一。本论文以Http Live Streaming技术为背景,详细介绍了Android平台架构和Android NDK开发,并在此基础上介绍并设计了移动流媒体直播系统,实现了无线网络视频的传输。最后,通过性能测试,实现了客户端采集编码功能。
文摘In this paper, we present an innovative design of multiple description coding with spatial-temporal hybrid interpola- tion (MDC-STHI) for peer-to-peer (P2P) video streaming. MDC can be effective in P2P networks because the nature of overlay routing makes path diversity more feasible. However, most MDC schemes require a redesign of video coding systems and are not cost-effective for wide deployment. We base our work on multiple state video coding, a form of MDC that can utilize standard codecs. Two quarter-sized video bit streams are generated as redundancies and embedded in the original-sized streams. With MDC-STHI, the nodes in P2P network can adjust the streaming traffic to satisfy the constraints of their devices and network environment. By design, the redundancies are used to compensate for missing frames, and can also be streamed independently to fulfill certain needs of low rate, low resolution applications. For better error concealment, optimal weights for spatial and temporal interpolation are determined at the source, quantized, and included in redundancies.
基金supported by National Key Technology Research and Development Program of China under Grant No.2015BAH08F01the joint fund of the Ministry of Education of People's Republic of China and China Mobile Communications Corporation under Grant No.MCM20160304
文摘Multi-channel can be used to provide higher transmission ability to the bandwidth-intensive and delay-sensitive real-time streams. However, traditional channel capacity theories and coding schemes are seldom designed for the real-time streams with strict delay constraint, especially in multi-channel context. This paper considers a real-time stream system, where real-time messages with different importance should be transmitted through several packet erasure channels, and be decoded by the receiver within a fixed delay. Based on window erasure channels and i.i.d.(identically and independently distributed) erasure channels, we derive the Multi-channel Real-time Stream Transmission(MRST) capacity models for Symmetric Real-time(SR) streams and Asymmetric Real-time(AR) streams respectively. Moreover, for window erasures, a Maximum Equilibrium Intra-session Code(MEIC) is presented for SR and AR streams, and is shown able to asymptotically achieve the theoretical MRST capacity. For i.i.d. erasures, we propose an Adaptive Maximum Equilibrium Intra-session Code(AMEIC), and then prove AMEIC can closely approach the MRST transmission capacity. Finally, the performances of the proposed codes are verified by simulations.
基金partially supported by the National Natural Science Foundation of China under Grants No. 610202380, No. 60932007Major Program of National Natural Science Foundation of China under Grant No. 60932007+2 种基金Tianjin Research Program of Application Foundation and Advanced Technology under Grant No. 12JCQNJC00300Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20110032120029the Innovation Foundation of Tianjin University
文摘To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks, a cross-layer design framework that jointly selects the Transmission Policy (TP) for SVC video frames, assigns OFDMA subcarriers, and allocates power for each subcarrier is proposed. We apply the dual decomposition method to the problem, and obtain a TP selection subproblem for each SVC video adaptation and a resource allocation subproblem of Joint Subcarrier, Relay and Power Allocation (JSRPA). A second level of dual decomposition is used to divide the JSRPA problem into independent subcarrier subproblems. The proposed Crosslayer Trade-off Optimization (CTO) algorithm is sub-distributed with significantly low complexity. A performance evaluation with typical SVC video traces demonstrates that the proposed algorithm is able to converge and efficiently achieve the optimal trade-off between the video quality and energy consumption at the MSs for uplink SVC streaming.
文摘Over the past years, we have witnessed an explosive growth in the use of multimedia applications such as audio and video streaming with mobile and static devices. Multimedia streaming applications need new approaches to multimedia transmissions to meet the growing volume demand and quality expectations of multimedia traffic. This paper studies network coding which is a promising paradigm that has the potential to improve the performance of networks for multimedia streaming applications in terms of packet delivery ratio (PDR), latency and jitter. This paper examines several network coding protocols for ad hoc wireless mesh networks and compares their performance on multimedia streaming applications with optimized broadcast protocols, e.g., BCast, Simplified Multicast Forwarding (SMF), and Partial Dominant Pruning (PDP). The results show that the performance increases significantly with the Random Linear Network Coding (RLNC) scheme.
文摘The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Government Area of Akawa Ibom State in Nigeria were carried out using standard analytical procedures. The parameters investigated were temperature(Temp.), hydrogen ion concentration(pH), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO) and biochemical oxygen demand (BOD). Correlation analysis carried out between pairs of variables showed that only the correlation coefficients between TDS and DO in ANS( p <0.05); Temp. and TDS in IES ( p <0.05) and between Temp. and TDS in AIS ( p <0.01) were significant. None of the pairs of the variables in NDS showed any significant correlation. The coefficients of variation for the parameters were also computed and used in determining their stability in the water. The possible effects of these variables on each other and on the aquatic ecosystem were discussed.
文摘针对智能交通管理设备本身缺乏安全监管,传统视频监控延迟高、画质低、稳定性差的问题,提出一种基于FFmpeg的多线程编码视频流传输方案。通过FFmpeg调用h264_nvenc编码器,实现宏块行级的GPU多线程加速,降低编码延迟。使用Visual Studio 2019和QT15.5开发基于FFmpeg的音视频处理软件,对多路视频流进行封装、推流,并搭建Nginx流媒体服务器进行分发。通过实验表明,该系统整体的传输延迟低于1 s,且拥有良好的率失真特性,监控画面清晰、稳定性高,实现了对交通管理设备实时稳定的安全监控。
