Friday, April 15, 2005

Audio and Video Preservation Reformatting: A Library of Congress Perspective

Another annotation:

Fleischauer, Carl. “Audio and Video Preservation Reformatting: A Library of Congress Perspective.” Paper delivered the Preservation Conference (Digital Technology vs. Analog Technology), National Archives at College Park, March 27, 2003. Available online at (accessed 15 Apr. 2005).

This paper by Library of Congress Project Coordinator of the Office of Strategic Initiatives, Carl Fleischauer was delivered at the 2003 NARA Preservation Conference “Digital Technology vs. Analog Technology.” It delivered six many points relating to reformatting analog materials to make them digital. Fleischauer talked about many of the approaches which the Library of Congress has taken towards preserving original formats and creating preservation digital masters for long-term preservation and access. His paper talks about videotape as well as audiotape—the former being an area where both technological systems and preservation practice still preserving.

One of the most enlightening points which Fleischauer makes relates to digital videotape formats. These formats contain signals whose digital information that is compressed. Compression (even those which employ lossless algorithims) introduce digital artifacts which produce inferior copies, much as copying an analog object would. The same can be said in the audio realm for digital audio tapes and minidiscs, whose materials are encoded with similar algorithims. Because of the large size of files and the cost of storage of uncompressed video is prohibitive at the present time, video preservation is still in its infancy when it comes to the digital realm.

Fleischauer also notes that the goal of reformatting sound and video is not transformation, as it is in book and paper microfilming projects. There is a transformation in the physical medium; but ideally, it should still be the same experience: listening to sounds and watching images that are true to their original capture, often done in archives without noise reduction or any other sort of “enhancement.” In video reformatting, often the elements (chrominance (or color) and luminance (or light) of a picture are combined together as a “composite signal,” rather than a “component signal” which separates these elements—often resulting in greater fidelity of image. The Library of Congress is currently experimenting with a prototype for video, much as they did for audio.

The current challenges for any sort of reformatting revolves around perceptual elements of a recording. What we can hear or see is only a small percentage of the total spectrum of sound and visual frequencies. What information then is worth recording? Do you have the equipment to play back all the frequencies? Can you really tell the differences? While one might not be able to tell, often what is perceived is not there: the high frequencies often contain harmonic overtones which are integral to the complete aural experience and are useful in re-mastering recordings.

Many of Fleischauer’s comments relate to best practices in transferring and reformatting digital objects at the highest possible resolution. He does make the point that not all institutions are ready for these high-price preservation solutions and storage formats. Intermediate solutions are needed and should be used in accordance with ethical treatment of the original sound documents. Digital preservation reformatting should be a tool in a preservation’s toolbox, but more work should be done towards long-term preservation of the original source recordings.


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