One Format Does Not Fit All: FADGI Audio-Visual Working Group’s Diverse Approaches to Format Guidance

This is the first in a two-part update on the recent activities of the Federal Agencies Digitization Guidelines Initiative. This article describes the work of the Audio-Visual Working Group. The second article, to be published on November 4th 2013, describes the work of the Still Image Working Group.

Macroblocking: demolish the eerie ▼oid by Rosa Menkman on Flickr turns video errors into art.

I wish I had a quick and easy answer when colleagues ask what file format they should use to create and archive digital moving images. My response usually starts out with “well, it depends.” And indeed it does depend on a wide variety of factors. Factors like what they want to achieve with the file, what equipment and storage space is available, are they reformatting old videotapes or creating new born-digital material? The list of considerations that can impact the decision goes on. As a community, our general rule is to “make the best file that you can afford to create and maintain” but what makes one format better than another in a given situation?  (BTW: in this context, the term file format is understood to mean both the file “wrapper,” e.g. mov, avi, and mxf, and the encoding in the wrapper, e.g., uncompressed, H.264, and JPEG 2000.)

The Federal Agencies Digitization Guidelines Initiative Audio-Visual Working Group, with active members from across the Library of Congress including the Packard Campus for Audio-Visual Conservation and American Folklife Center as well as the National Archives and Records Administration, Smithsonian Institution Archives, and National Oceanic and Atmospheric Administration among others, has four subgroups working on informative guidance products to help answer the age-old question, “what should I do with my moving image collections?”

Video Efforts

The lead video effort, now in its third year, entails the development of a specification for the use of the MXF format, in effect a special profile of this wrapper tailored to serve preservation.  The specification is dubbed AS-07 and it is not only of general interest to the community but directly supports the work of the Packard Campus, where a version of MXF with JPEG 2000 picture encoding has been in use for several years.  Everyone expects that the publication of the AS-07 specification will increase the adoption of this format.  Meanwhile, however, there are other formatting options to consider, especially by smaller archives or for classes of content that are less complex than, say, the broadcast collections that are an important part of the Packard Campus holdings.

The Working Group’s interest in exploring this wider range of options has led to the formation of the Digitized Video subgroup, spearheaded by staff from the NARA’s Video Preservation Lab.  Taking a lead from the work of the FADGI Still Image Working Group, this subgroup is building a matrix to compare target wrappers and encodings against a set list of criteria that come into play when reformatting analog videotapes. The evaluation attributes include format sustainability, system implementation, cost, and settings and capabilities. The matrix and companion documents will be available for review on the FADGI website in the coming months.

The just-off-the-ground Born-Digital Video subgroup, led by staff from the American Folklife Center at the Library of Congress, is taking a lifecycle approach to born-digital video by focusing on guiding principles. Through visual examples and case histories, the subgroup’s product will illustrate the cause and effect of the range of decisions to be made during the creation and archiving lifecycle of a born-digital video file. This work will be geared for both file creators (such as videographers and others who create new digital video files) and file archivists (such as librarians and archivists and others who receive files from creators and have to archive and/or distribute them). For file creators, we want to emphasize the advantages of starting with high quality data capture. For file archivists, we want to explore options for identifying the composition of video files and evaluating their characteristics to better understand if action is warranted and if so, when the action needs to be taken.

Both the Digitized and Born-Digital video subgroup efforts build on the useful 2011 report by George Blood for the Library of Congress titled Determining Suitable Digital Video Formats for Medium-term Storage.  In addition, our format comparisons will support the ongoing work of the International Association of Sound and Audiovisual Archives as they draft a general guideline for video preservation.

Motion Picture Film Efforts

The Film Scanning subgroup, led by staff from NARA’s Motion Picture Preservation Lab, is addressing the issues of digitizing motion picture film. The first product from this group will be an outline of technical components to address when outsourcing film scanning to commercial vendors with a goal towards improving access. Other efforts, including the Academy of Motion Picture Arts and Sciences Academy Color Encoding System, are focused on improving archival master formats but until these efforts are ready for prime time, the community is looking for guidance on interim solutions that take possible future uses into account.