Paradigms and Protocols for Real-Time Digital Video and Audio Services in Distributed Computing Systems

随着网络和存储设备开始提供非常高的容量，分布式系统可以支持数字视频和音频领域的通信和文件服务。该项目研究了多媒体服务的范例和协议，这些服务支持可视/语音对话，并允许选择性地存储/检索对话的部分内容。会议被用作访问任何多媒体服务的基本范例。例如，为了检索数字视频，客户端与视频文件服务建立对话；为了记录对话的部分内容，文件服务作为对话的一方加入，将其转换为会议；为了在空闲时间娱乐，客户端加入HDTV服务的后台会议。该项目正在为一个强大的多层次多渠道会议范式开发精确的模型和连接管理机制。该项目使用会话文件系统存储/检索多媒体数据。文件系统处理千兆字节大小的文件并处理媒体间同步。多媒体通信需要协议提供性能保证，并支持多个媒体流，同时保持流之间的时间关系。该项目研究了这些协议和算法的设计，用于将资源分配给性能保证的通道。研究的结果是软件架构、协议和算法，将使多媒体计算系统取代现实世界的服务，如物理邮件、电话、新闻、广告和视频/音频娱乐。

With networks and storage devices beginning to offer very high capacities, distributed systems can support communication and file services in the digital video and audio domains. The project investigates paradigms and protocols for multi-media services that support visual/voice conversations and allow selective storage/retrieval of parts of a converstation. Conferencing is used as the basic paradigm for accessing any multi-media service. For instance, to retrieve digital video a client establishes a conversation with the video file service; to record parts of a conversation, the file service joins as a party to the conversation transforming it into a conference; for entertainment during idle periods, a client joins a background conference with the HDTV service. The project is developing precise models and connection management mechanisms for a powerful multi-level multi-channel conferencing paradigm. The project uses conversational file systems for storage/ retrieval of multi-media data. The file systems handle gigabyte file sizes and handle inter-media synchronization. Multi-media communication requires protocols that provide performance guarantees, and support multiple media streams while preserving temporal relationships among the streams. The project investigates the design of such protocols and algorithms for allocation of resources to performance guaranteed channels. The outcome of the research is software architectures, protocols, and algorithms that will enable multi-media computing systems to replace real-world services such as physical mail, telephony, news, advertising and video/audio entertainment.