Internet多媒体数据流实时传输协议的研究及其应用

对java平台从多媒体数据流实时传输的运用方面进行了介绍。对网络多媒体中的RTP、RSVP、RTSP和IPV6等数据流实时传输的关键协议从实时传输意义方面进行了分析。     

流媒体技术讲座 第2讲 实时传输协议

流式传输需要合适的传输协议，以保证实时媒体及时传送到客户端。目前主要的实时传输协议有：用于Internet上针对多媒体数据流的实时传输协议（RTP，Real-time Transport Protocol)，与RTP一起提供流量控制和拥塞控制服务的实时传输控制协议（RTCP，Real-time Transport Control Protocol),定义了一对多的应用程序如何有效地通过IP网络传送多媒体数据的实时流协议（RTSP，Real-time Streaming Protocol),以及正在开发的Internet上的资源预订协议（RSVP，Resource Reserve Protocol)。本文对这种主要协议进行介绍。     

视频实时传输的RTP实现

分析了现有的网络协议在支持网络多媒体传输中面临的问题，介绍了实时传输协议RTP的概念和功能，讨论了RTP在网络视频实时传输中的实现。     

基于DMIF体系的MPEG-4传输

在对MPEG-4的传送多媒体集成框架（DMIF）的研究和实时传输协议（RTP）对于MPEG-4封装的研究的基础上。提出了一种基于DMIF体系的MPEG-4实时传输方案。本方案的适用性很强．可以用在远程监控、远程教学等众多实时传输领域。     

多媒体传输的实时传输协议分析

一、概述 为了实现带有实时性质的数据(例如交互式的话音和视频数据)从端到端的网络传递业务,由Internet的音频-视频传输工作组提出了实时传输协议,它的主要设计目标是满足多参与者多媒体会议的技术需要,但其应用范围远不止于此。下面我们首先对它作一个概括性的介绍。RTP的基本特征 实时传输协议(Real-time Transport Protocol,简称RTP)很适合用于发送多媒体数据(如音频流或视频流)给一个接收者(单播)或多个接收者(多播)。数据通常单方向传送,接收方不给确认信息。 与RTP同时存在的另一个协议是实时传输控制协议(RTCP),它让接收者给RTP发送者一个反馈信息(以及反之)。例如,接收应用程序可以告诉发送应用程序减慢视频流的速度。当速度减慢后,视频图象仍然可以显示,但可能出现跳动或分辨率降低。RTCP规范中的准则可以帮     

多媒体远程教学系统实时传输解决方案

有效的传输机制是保障多媒体远程教学系统这样的分布式多媒体系统应用需求的关键。针对分布式多媒体应用,结合流媒体的传输控制协议,提出了一种远程教学系统实时传输解决方案:通过RTSP(实时流传输协议)建立和控制多媒体会话,RTP(实时传输协议)承载实时信息的传输,RTCP(实时传输控制协议)监控数据的传输状态,RSVP(资源预留协议)预约传输所需的Internet资源保证服务质量。该传输方案不仅适用于远程教学系统,也适用于其他基于Internet的实时多媒体应用系统。     

流媒体技术综述

流媒体(streaming media)是一种新兴的网络传输技术，在互联网上实时顺序地传输和播放视／音频等多媒体内容的连续时基数据流，流媒体技术包括流媒体数据采集、视／音频煽解码、存储、传输、播放等领域。本文分别从流媒体的技术原理、传输方式、传输协议等方面对流媒体做出阐述。     

流媒体技术讲座 第2讲 实时传输协议

流式传输需要合适的传输协议,以保证实时媒体及时传送到客户端。目前主要的实时传输协议有:用于Internet上针对多媒体数据流的实时传输协议(RTP,Real-timeTransportProtocol),与RTP一起提供流量控制和拥塞控制服务的实时传输控制协议(RTCP,Real-timeTransportControlProtocol),定义了一对多的应用程序如何有效地通过IP网络传送多媒体数据的实时流协议(RTSP,Real-timeStreamingProtocol),以及正在开发的In-ternet上的资源预订协议(RSVP,ResourceReserveProtocol)。本文对这几种主要协议进行介绍。     

可靠的实时传输协议

介绍了适合于当前多媒体通信的实时传输协议——（RTP），并针对RTP的一些不足提出了一种新的可靠的实时传输协议，它提供了错误恢复、流量控制和拥塞控制等功能。     

扫描型红外焦平面探测器图像实时传输系统

探讨了一种扫描型红外焦平面探测器(IRFPA)图像实时传输系统的原理、结构及其实现。根据系统指标要求,提出了一种基于FPGA的红外图像实时传输系统,并利用光纤传输技术与USB协议来实现。该方案不仅实现了扫描型IRFPA图像的实时传输,而且实现了双模式显示,为之后图像融合、目标跟踪奠定了基础。     

Multipath video transport over ad hoc networks

Real-time multimedia transport has stringent bandwidth, delay, and loss requirements. It is a great challenge to support such applications in wireless ad hoc networks, which are characterized by frequent link failures and congestion. Using multiple paths in parallel for a real-time multimedia session (called multipath transport) provides a new degree of freedom in designing robust multimedia transport systems. In this article, we describe a framework for multipath video transport over wireless ad hoc networks, and examine its essential components, including multistream video coding, multipath routing, and transport mechanisms. We illustrate by three representative examples how to extend existing video coding schemes in order to fully explore the potential of multipath transport. We also examine important mechanisms in different layers for supporting multipath video transport over ad hoc networks. Our experiments show that multipath transport is a promising technique for efficient video communications over ad hoc networks.     

ARC: the analytical rate control scheme for real-time traffic in wireless networks

Next-generation wireless Internet (NGWI) is expected to provide a wide range of services including real-time multimedia to mobile users. However, the real-time multimedia traffic transport requires rate control deployment to protect shared Internet from unfairness and further congestion collapse. The transmission rate control method must also achieve high throughput and satisfy multimedia requirements such as delay or jitter bound. However, the existing solutions are mostly for the wired Internet, and hence, they do not address the challenges in the wireless environments which are characterized by high bit error rates. In this paper, a new analytical rate control (ARC) protocol for real-time multimedia traffic over wireless networks is presented. It is intended to achieve high throughput and multimedia support for real-time traffic flows while preserving fairness to the TCP sources sharing the same wired link resources. Based on the end-to-end path model, the desired behavior of a TCP source over lossy links is captured via renewal theory. The resulting asymptotic throughput equation is designated as the driving equation for the proposed rate control method. Performance evaluation via simulation experiments reveals that ARC achieves high throughput and meets multimedia traffic expectations without violating good citizenship rules for the shared Internet.     

An architecture for real-time multimedia communication systems

A multimedia communication system includes both the communication protocols used to transport the real-time data and the distributed computing system (DCS) within which any applications using the protocols must execute. The architecture presented attempts to integrate these communications protocols with the DCS in a smooth fashion in order to ease the writing of multimedia applications. Two issues are identified as being essential to the success of this integration: the synchronization of related real-time data streams, and the management of heterogeneous multimedia hardware. The synchronization problem is tackled by defining explicit synchronization properties at the presentation level and by providing control and synchronization operations within the DCS which operate in terms of these properties. The heterogeneity problems are addressed by separating the data transport semantics (protocols themselves) from the control semantics (protocol interfaces)     

Delay-sensitive and multimedia communication in cognitive radio sensor networks

Multimedia and delay-sensitive data applications in cognitive radio sensor networks (CRSN) require efficient real-time communication and dynamic spectrum access (DSA) capabilities. This requirement poses emerging problems to be addressed in inherently resource-constrained sensor networks, and needs investigation of CRSN challenges with real-time communication requirements. In this paper, the main design challenges and principles for multimedia and delay-sensitive data transport in CRSN are introduced. The existing transport protocols and algorithms devised for cognitive radio ad hoc networks and wireless sensor networks (WSN) are explored from the perspective of CRSN paradigm. Specifically, the challenges for real-time transport in CRSN are investigated in different spectrum environments of smart grid, e.g., 500 kV substation, main power room and underground network transformer vaults. Open research issues for the realization of energy-efficient and real-time transport in CRSN are also presented. Overall, the performance evaluations provide valuable insights about real-time transport in CRSN and guide design decisions and trade-offs for CRSN applications in smart electric power grid.     

Ad Hoc上的新协议——流实时传输协议

在Ad Hoc网络中传输多媒体数据会受到网络拓扑变化和无线信道干扰的限制.多流实时传输协议MRTP(multi-flow real-time transport protocol)是一种可以分配和传输多个视频数据流的新协议.它结合多描述编码和多径传输,能提高无线对等网络上视频传输的效率和质量.     

Supporting real-time IP multimedia services in UMTS

UMTS, the successor of GSM, is evolving toward a future wireless all-IP network. We explain how it will support real-time IP multimedia services, as these services are expected to drive the adoption of wireless all-IP networks. We not only focus on the centerpiece of IP multimedia support, the IP multimedia subsystem, but also include the GPRS transport capabilities and OSA middleware capabilities. This helps to explain how the IMS fits in with, and builds upon, other pieces of the UMTS network. We analyze the pros and cons of providing IP multimedia session control capabilities as opposed to just providing basic IP connectivity, and highlight selected features of the IMS design for discussion.     

A multimedia synchronization model and its implementation intransport protocols

An implementation of a synchronization mechanism in transport protocol to support multimedia applications over a packet or cell switched network is proposed. In designing such a mechanism for practical use, ease of implementation and capability of handling random delay of packets are two key issues for success. Since the random delay of packet or cell switched networks makes synchronization among media more complicated after the transmission across the network, a model which considers the random transmission delay is hence required to specify the temporal relationship among media. Therefore, a real-time synchronization model is presented to satisfy this requirement in the paper. Based on the proposed synchronization model, a transport protocol, namely the multimedia synchronization transport protocol (MSTP), is designed and implemented. We have implemented a prototype system using the MSTP protocol and built a simulation system for the wide area network (WAN) environment in order to evaluate the performance of the MSTP protocol     

多媒体网络可靠性分析系统实现

基于MDI的视频质量分析模型,设计并实现了多媒体网络可靠性分析系统。首先,基于RTP/RTCP协议,实现了多媒体网络视频的实时远程传输及播放。然后,将多媒体网络的视频主观评价方法与客观评价方法相结合,提出了一种综合可靠性评价方法,相较于目前的网络可靠性分析方法,综合可靠性评价方法更加全面、可信。最后,通过实验给出了可靠性分析系统的结果。