vst(1)

NAME

VST - Video Server Toolkit

SYNOPSIS

Video Server Toolkit is a software platform enabling developers to construct high-performance, scalable video server applications on Silicon Graphics servers.

DESCRIPTION

The core VST software provides management of a simple database of clips (the Clip Cache), a control API for managing and operating VST, and a core library which supports various External Interface Modules.

A single VST instance manages all playback and record operations for a single video server. However, each VST instance supports multiple logical playback/record units. Each unit manages a single signal port but may be controlled by multiple control ports. A signal port may support multiple logical units subject to the device-sharing characteristics of that port.

External Interface Modules

The VST interface modules fall into five categories:

Storage: The storage interfaces provide access to the storage systems where the clip content is stored (the Clip Cache). The XFS-based disk interface module provided with the base VST software is sufficient for most applications.

Media: The media I/O interfaces provide access to the "signal" ports of the video server. A signal port is any video or data networking I/O port over which the digital media will be transmitted or received. Each type of I/O port will typically have its own VST interface module.

Format: The format interfaces provide handlers for accessing specific digital media storage formats. For instance, the base "stream" format handler is suitable for stream-based formats such as MPEG. The "vframe" format handler is specialized toward variable-length, frame-oriented video/audio material.

Control: The control interfaces implement external control protocols to allow integration with a variety of automation controllers and digital media applications. The VST core control logic provides a wide variety of control capabilities which should be sufficient to implement most machine control protocols.

Archive: The archive interfaces provide support for content archiving (both storage and retrieval) on external archive systems.

Control Interfaces

The base VST software three external control protocols:

Louth Video Disk Communications Protocol: This protocol, defined by Louth Automation, provides full-featured control of the VST via RS-232, RS-422, and TCP/IP. The VST Louth processor supports back-to-back play and record (subject to restrictions imposed by the video I/O port capabilities) and archive management.

Multiport Video Computer Protocol (MVCP): This protocol, defined by Silicon Graphics, provides full-featured control of VST via TCP/IP. The protocol processor supports archive management, multiple-unit control, and event monitoring. The protocol command set is documented in mvcp(5).