Managing storage in file-based workflows
Aug 1, 2010 12:00 PM, By Paul Turner
A complete file-based workflow should include concepts of centralized storage, clip management and overall process management.
Figure 2. Example of a clip containing multiple essence files
Select figure to enlarge.
The simplest level of management is file-based, and in this case the user, librarian or administrator simply opens a window into the file system in question and interacts directly with the files. While this is basically a “no cost” option, it has several drawbacks. First, the client can only interact with one file system at a time. Without consolidation for the purposes of management, the broadcaster cannot manage the same files on multiple file systems. Second, users must understand the storage system's folder structure if they want to locate the material in question. Finally, and probably most importantly, users must understand the file structure of a specific media item. Clips are often made up of separate wrapper, video, audio, time code and VBI files. (See Figure 2.) If users don't understand which files belong to particular clips, they run the risk of moving or deleting the wrong files and creating problems that cascade throughout the workflow. A system that relies on user skill is unlikely to bring about significant improvements in workflow efficiency.
A second approach is to manage the storage systems at the clip level. In this case, the management system takes on responsibility for associating all of the files that make up a clip, and the users' interaction occurs at the clip level. Much more intuitive for the user, this model avoids the possibility of human error, such as the wrong essence file being moved or deleted, and allows some process automation to be enacted. Clips can be automatically moved, transcoded, archived or deleted based on a set of business rules. Once certain criteria are achieved (such as approval of an edit by an edit supervisor or completion of a file-based QC stage), an action may be initiated on the clip as a whole, with an associated improvement in overall system throughput.
Finally, the management of stored material may be approached as management of specific “assets.” In this context, an asset would be a conglomerate of media, such as all of the copies of a particular clip, regardless of location, format or bit rate. Through this approach, storage management can be extended enterprise-wide. A single search query can turn up all copies of a particular clip, even though those copies may be scattered across multiple file systems in the facility. Implementing this model yields substantive process improvements as the use of a single search operation, rather than individual searches on each file system within the facility, reduces the overhead involved in even the most mundane of management tasks. When coupled with clip-based storage management, the true efficiencies of a file-based workflow can begin to be realized.
Conclusion
A well-thought-out storage infrastructure is fundamental to a successful file-based workflow. Only when all elements are optimized can real workflow benefits be attained by the broadcaster. Solutions exist within the marketplace, and it's up to designers to evaluate each according to key design parameters and determine which storage system is most appropriate for their specific needs.
Paul Turner is vice president, broadcast market development, for Omneon.
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