Magnetic tape is the world's most common media for audiovisual recording. Archives, broadcast networks, and consumers have used magnetic tape to store and play back their valuable audiovisual content because it has been inexpensive and plentiful. Some common professional magnetic media formats are BetacamSP, U-matic, DigiBeta, D1, D3, and BetacamSX; among consumers, VHS has been the dominant format. Cameras to record and players to play back magnetic media are also commonly available in both consumer and professional cost ranges.Long considered advantages, the ubiquitous and inexpensive nature of the media also presents significant challenges to those concerned with the preservation of audiovisual heritage. Over the decades, more than 65 magnetic media formats have been introduced to the market. Many of these formats did not survive. With the demise of a format comes the obsolescence of its playback equipment, rendering countless hours of material unplayable.In addition to issues related to the availability of magnetic media and its equipment, the physical medium itself has limitations. Though cheap and plentiful, magnetic tape is fragile and short-lived. Depending upon storage conditions, the life expectancy of modern magnetic tape is approximately 20 years. After that period of time magnetic media will degrade. From an archival perspective, twenty years is not a long time. The physical degradation of magnetic media poses considerable challenges to audiovisual archivists. Cheap and plentiful meets fragile and short-lived… so much media resides on cassettes and reels that no force on earth can save it all from degradation.Enter migration: the only way to preserve content recorded on magnetic media is to migrate the information to new tape, or, thanks to recent advances in compression and declining storage prices, to digital media. Unlike simple video duplication, audiovisual migration is an esoteric and expensive art. Few companies can do it, and costs range from 250 to 500 per finished hour of media, with pricing based on the idea that all tapes are damaged when they arrive.A review of traditional audiovisual migration is helpful here. Archives and other content holders first select a portion of their collection for migration. The tapes are inventoried, packed, and shipped to the migration company. Upon receipt, each tape is inspected and cleaned. It is presumed that all tapes will exhibit some form of deterioration and the cleaning process will reveal the extent of the damage. Tapes requiring little or no restoration continue through the migration process. The majority of tapes will only need minimal cleaning for playback. Tapes requiring extensive restoration are handled by specialists who use a variety of methods to resurrect the tape to a point where it can be played back and recorded onto a new master. In either case, humans perform all actions needed to migrate the content of a batch of tapes to new tape stock. A badly deteriorated tape could go through two to three specialists, each with their own skill level and area of expertise, before successful migration. Note that the end result of this labor-intensive process is one new master per source tape, and nothing more.The approach to preserving tapes detailed above has three glaring problems. The first is cost. Specialized facilities, knowledgeable staff, and professional, properly serviced equipment are expensive to maintain. High costs are inevitably passed onto the customer. The second problem is scalability. A top-flight team of 2-3 specialists working 40-hour weeks could migrate approximately 5,000 hours of content per year. The processes involved when using human labor simply do not scale as you increase the size of the collection of tapes. Thirdly, the majority of tapes arriving at video migration facilities are in fair to good condition, contrasting with the established practice of treating every tape as if it were damaged. These three problems – coupled with the dangers of shipping a collection away from its home, the costs of insurance, the time to process a job, and the absence of meaningful metadata about the migration process – clearly illustrate where there is room for improvement in this process.Current manual processes limit the preservation of our audiovisual heritage. Traditional methods simply cannot keep up with the vast amount of magnetic media stored in the world's archives. The costs are too high, the output too low. Without a fundamental change, much of the magnetic media holding the world's audiovisual heritage will disintegrate before its content can be saved.Looking closely at the manual migration process, it is useful to analyze where human resources are spent. In a migration facility, human resources are spent on every tape. Rather than having trained engineers examine only the problem tapes, every tape is visually inspected. The pricing structure for a migration job reflects this inefficiency – tapes in good condition can cost as much to migrate as tapes that have extensive damage.
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Jan 6, 2010
Myriam B.C Aries + 2
Open Access