Due to the explosive growth of the Internet and increasing demand for multimedia information on the Web, streaming video over the Internet has received tremendous attention from academia and industry. Transmission of real-time video typically has bandwidth, delay, and loss requirements. However, the current best-effort Internet does not offer any quality of service (QoS) guarantees to streaming video. Furthermore, for video multicast, it is difficult to achieve both efficiency and flexibility. Thus, Internet streaming video poses many challenges. In this article we cover six key areas of streaming video. Specifically, we cover video compression, application-layer QoS control, continuous media distribution services, streaming servers, media synchronization mechanisms, and protocols for streaming media. For each area, we address the particular issues and review major approaches and mechanisms. We also discuss the tradeoffs of the approaches and point out future research directions.

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Streaming video over the Internet: approaches and directions

A plurality of data mover computers control access to respective file systems in data storage A network client serviced by any of the data movers can access each of the file systems If a data mover receives a client request for access to a file in a file system to which access is controlled by another data mover, then the data mover that received the client request sends a metadata request to the data mover that controls access to the file system The data mover that controls access to the file system responds by placing a lock on the file and returning metadata of the file The data mover that received the client request uses the metadata to formulate a data access command that is used to access the file data in the file system over a bypass data path that bypasses the data mover computer that controls access to the file system

File server system using file system storage, data movers, and an exchange of meta data among data movers for file locking and direct access to shared file systems

A storage controller has at least one physical data port for a data network including host processors. The storage controller is programmed to provide a plurality of virtual ports for access to storage, and a virtual switch for routing storage access requests from the physical port to the virtual ports. The virtual ports and the virtual switch are defined by software. The virtual ports appear to the hosts as physical ports in the data network. For example, in a Fiber-Channel network, the virtual ports have World Wide Names (WWNs) and are assigned temporary addresses (S_Ds), and the virtual switch provides a name server identifying the WWNs and S_IDs of the virtual ports. For convenient partitioning of storage among host processors, one or more virtual ports are assigned to each host, and a set of storage volumes are made accessible from each virtual port. A host can access storage at a virtual port only if the virtual port has been assigned to the host. Preferably, storage can be accessed through each virtual port by no more than one assigned host, although a shared volume may be accessible from more than one virtual port. The storage controller may provide a service for reporting to a host the virtual ports through which the host can access storage, and the storage volumes that are accessible to the host through each of the virtual ports.

Virtual ports for data transferring of a data storage system

A client is permitted to send data access commands directly to network data storage of a network file server after obtaining a lock on at least a portion of the file and obtaining metadata indicating storage locations for the data in the data storage For example, the client sends to the file server at least one request for access to a file In response, the file server grants a lock to the client, and returns to the client metadata of the file including information specifying data storage locations in the network data storage for storing data of the file The client receives the metadata, and uses the metadata to produce at least one data access command for accessing the data storage locations in the network storage The client sends the data access command to the network data storage to read or write data to the file For a write operation, the client may modify the metadata When the client is finished writing to the file, the client returns any modified metadata to the file server

File server system providing direct data sharing between clients with a server acting as an arbiter and coordinator

A system and method for indexing between video streams in an interactive video delivery system. The interactive video delivery system includes at least one media server which stores video streams having different presentation rates. In one embodiment, the system stores a normal play stream and one or more corresponding trick play streams. The trick play video streams are fast forward and/or fast reverse video streams. The system generates index tables or look-up tables between the normal play and trick play video streams which enable indexing between the streams, and uses these look-up tables to switch back and forth between the streams. In creating the index tables, the system first analyzes the normal play stream and creates a normal play time standard based on presentation timestamps from the normal play stream. The system then creates an index table or look-up table for each of the normal play and trick play video streams using the normal play time standard. Each index table includes an array of two-tuples, wherein the two-tuples are the normal play time standard and an index or offset into the respective stream. The index tables enable indexing between the streams. During video delivery, the system uses the respective index tables to switch back and forth between the normal play and trick play video streams.

System and method for indexing between trick play and normal play video streams in a video delivery system

Real-time processing of multimedia data is required of those who offer audio and video on-demand. This tutorial highlights the unique issues and data storage characteristics that concern designers. >

D.J. Gemmell

Papers

Multimedia storage servers: a tutorial