The fundamental elements of media workflows
Mar 1, 2009 12:00 PM, By Al Kovalick
Exception handling deals with hardware and software warnings, faults, errors and status messaging. When something is out of order, it should be registered and personnel notified to repair it. Exceptions may range from warnings of intermittent errors, to out-of-spec signals (audio peaks), to resource status (90 percent full), to a complete device failure. High-end infrastructure monitoring systems are available from traditional IT vendors. A/V specific solutions are available from several vendors.
Investing in monitoring and diagnostics products is a matter of return on investment for the most part. If you are offering services, such as creative tools by-the-hour or commercial program playout, then money spent on keeping the facility up and running is worth the investment.
Workflow agility
Agility is defined as the ability to move in a quick and easy fashion, or change directions quickly. Typically, media workflows are purpose-built — broadcast, post, animation, news, live events, DI and so on. It is prudent, as discussed, for form to follow function. Nonetheless, within the bounds of scale, future changes and reconfigurations, a workflow should be agile.
Loosely coupled designs
One key aspect of flexibility is the concept of loose versus tight coupled processes. This industry is built on tightly coupled designs — hard-wired, rigid, A/V systems with little flexibility for reordering, or quick reuse of components. Sure, SDI and AES/EBU audio links are routable, but this does not constitute a loosely coupled system.
Loosely coupled designs rely on the aggregation of distributed services. A service is a networked application function available for use by others. Examples are video transcoders, media encoders, transfer engines, 3-D render engines, a media asset management (MAM) searching engine and technical QA evaluation. Each function is available over a networked IP connection, is instantiated on an application server, provides a standardized access API and defines a performance QoS for each client user.
Given a collection of relevant services, a designer can configure them to perform useful operations. These services are scalable, reliable (based on methods explained above), reusable (the mantra of services design), and well-defined in terms of API interfacing, data structures and performance QoS.
One outstanding example of a services specification is defined by the W3C.org group. It has defined what is called Web services, and this includes specifications for all aspects of interfacing to services, securing, naming, addressing, finding, monitoring and so on. Despite the name Web services, these are not bound to the Web. They may be implemented across the Web or inside a secure enterprise environment. Google, Yahoo, Salesforce.com, Amazon, MySpace, and many others offer Web services (or similar RESTful services) for public and private use. Some enterprise media facilities use Web services for select applications. They are not a panacea for all aspects of a media workflow. Real-time A/V operations often require dedicated devices to meet their QoS specification, and Web services fall short today. Still, when real time is not an issue, workflows using Web services are practical and will see more light of day as the industry builds confidence in their practical value.
Thinking SOA
The SOA is broadly defined as an architecture of loosely coupled, wrapped services communicating via published interfaces over a common middleware layer. This definition is not universal; there are others, but this will suit our needs and scope. SOA is strongly linked to Web services and other related networked service concepts. It provides the discipline to create scalable, reliable, managed business and media workflows. Using the technology principles of service reuse, granularity, modularity and interoperability, an SOA provides a firm infrastructure for efficient applications deployment.
SOA is not a technology, but rather an approach — a framework for creating solutions. Its acceptance is growing in medium- to large-scale enterprise organizations. According to the analysis firm Forrester Research, at least 63 percent will have one or more SOA implementations by the end of 2008. Looking forward, many media organizations will be using SOA principles. This affects equipment design because vendors will begin to provide service interfaces on their products to better interface into SOA environments. In the end, this creates more flexible workflows and efficient facilities.
Conclusion
The definition of workflow as “a set of sequential steps needed to complete a job” is deceptively trivial. Yet, behind these few words lies a world of sophistication in terms of design, planning, documentation, implementation and operational aspects. By using these concepts and maxims as a guide or checklist, architects, designers and engineers will have additional confidence in the merits their workflow solutions.
Al Kovalick is a strategist and fellow with Avid Technology and author of “Video Systems in an IT Environment — The Basics of Networked Media and File-Based Workflows (second edition 3/09)” (www.theAVITbook.com).
Editor's note: This article was previously published in the November/December, SMPTE Motion Imaging Journal, copyright, 2008, SMPTE.
| Want to use this article? Click here for options! |  |
