The beginning is a very fine place to start indeed for the Federal Agencies Digitization Guidelines Initiative Born Digital Video subgroup of the Audio-Visual Working Group. As mentioned in a previous blog post, the FADGI Born Digital Video subgroup is taking a close look at the range of decisions to be made throughout the lifecycle of born digital video objects, from file creation through archival ingest and access delivery. Through case histories from federal agencies such as National Archives and Records Administration, Smithsonian Institution Archives, and National Oceanic and Atmospheric Administration, Library of Congress, Voice of America and American Folklife Center, we are exploring the truth and consequences when creating and archiving born digital video. In this blog post, well look at some of our guiding principles for creating born digital video.
But as Julie Andrews says, lets start at the very beginning. What do we mean by born digital video? Quite simply, its video that is recorded to digital file at the point of creation. Born digital video is distinct from digitized or reformatted video, a label used to describe the result of translating the analog signal data emanating from a video object into a digitally encoded format. FADGIs Reformatted Video subgroup is developing a matrix which compares target wrappers and encodings against a set list of criteria that come into play when reformatting analog videotapes.
The first set of FADGI BDV case histories highlight what we call advice for shooters (a.k.a. videographers), and by extension, the project managers within cultural heritage institutions who are responsible for the creation new born digital video files – especially determining the technical file specifications. Its important to recognize that the FADGI target audience for these case histories isnt Hollywood or commercial entertainment producers. Its the cultural heritage community or smaller archives who create non-broadcast classes of content recording such as oral histories. A great example is the Civil Rights History Project at AFC. These types of projects have the opportunity to spec out the born digital video deliverable from the very beginning and end up with a file that is ingest ready for preservation and access systems.
The goal of the case histories project is to use guiding principles to illustrate the advantages of starting with high quality data capture from the very start. Two examples of FADGIs guiding principles for creating born digital video include:
- Create uncompressed video instead of compressed video. Compressed video reduces the amount of data in a file or stream. Although a reduced amount of data can be beneficial for easing storage, transfer, and play-out requirements, it generally introduces additional technical complexity which can have a negative impact on usability of the file over time. Uncompressed video retains all the visual information captured at the selected resolution, which is preferable for preservation purposes.
- If compression is required, use lossless compression over lossy compression. Lossless compression uses algorithms that restore the compressed data after decompression. It is essentially reversible compression. Lossy compression permanently alters or deletes the compressed data. If data reduction gains are significant enough to warrant using the added complexity of compressed files, lossless compression is preferred to preserve video quality.
These are just two examples that focus on the video encoding. The guiding principles also cover considerations for file wrapper or container capabilities, format sustainability and more general project concerns.
But heres the thing: our case histories dont always follow our own guiding principles. And thats just fine by us. None of us live in a utopian world where digital storage is abundant and systems are completely interoperable. We all have to make choices and compromises to work within our restraints. Uncompressed video files can be huge and a burden to manage and maintain. Lossy compression can be appropriate for certain projects. The guiding principles should all be read with the caveat “if you have the option….” Sometimes, you simply don’t have the option for a myriad of reasons. But when you do have the option, the guiding principles highlight the advantages of high quality data capture. The important take-away from the case histories project is the choices made during the file creation process will have impacts on the long term archiving and distribution processes and its essential to understand what those impacts are and have a plan for to resolve any conflicts.
Our hope is that these guiding principles and case histories help us start to flesh out more specific format guidance for born digital video but thats in the future. The case history project, which will be published on the Federal Agencies Digitization Guidelines Initiative website this spring, is the first step towards understanding where we are as a community and what we can learn from each other.