Digital Preservation of Moving Image Material?

Bibliographic reference
BESSER Howard, Digital Preservation of Moving Image Material? ( en ligne), UCLA School of Education & Information Studies, Accepted for publication in: The Moving Image, Fall 2001 written March 2001. Text accessible : http://www.gseis.ucla.edu/~howard/Papers/amia-longevity.html


D.C Title : Digital Preservation of Moving Image Material?
D.C Creator : BESSER Howard
D.C Subject : digital imaging/digital preservation/film archives/moving image/preservation
D.C Description : this text explains the various "approaches to preserving digital materials and the author points to two paradigm shifts that will be likely for moving image preservation."
D.C Publisher : UCLA School of Education & Information Studies
D.C Date : 2001-03-01
D.C Type : Text
D.C format : html.
D.C Identifier : http://www.gseis.ucla.edu/~howard/Papers/amia-longevity.html
D.C Source : http://www.gseis.ucla.edu/
D.C Language : english
D.C Relation : http://www.gseis.ucla.edu/~howard/
http://sunsite.berkeley.edu/Longevity/
D.C Coverage : -
D.C Rights : -


This text is an extract of the original text.

Digital Preservation of Moving Image Material?

Accepted for publication in: The Moving Image, Fall 2001 written March 2001
Howard Besser UCLA School of Education & Information Studies http://www.gseis.ucla.edu/~howard/

http://sunsite.berkeley.edu/Longevity/

"Digital imaging and broadband networks are changing the moving image production and distribution process. In response to these changes, preservationists need to not only re-think some of their daily practices, but also need to engage in some fundamental paradigm shifts in how they view the preservation process. This article first describes some of the technological-induced changes in moving image production and distribution. It then discusses how those changes are altering viewer habits and expectations, and how those in turn affect how we will need to deliver and store moving image materials. Then the article explains the various approaches to preserving digital materials. Finally, the author points to two paradigm shifts that will be likely for moving image preservation: from preserving completed works as a whole to asset management, and from preserving an artifact to preserving disembodied content.

Introduction

The advent of digital technology is leading to widespread changes in moving image production. These changes are reverberating through all aspects of moving images -- from distribution channels to user expectations. Though the timelines and extent of many of these changes are overly inflated, these changes are still likely to force a dramatic shift in the film preservation paradigm. Key shifts will cluster around 2 areas: the first -- a movement from saving finished works as a whole to an asset-management approach that deals both with component parts of works and with ancillary materials that relate to the work. The second -- learning how to shift from a mode focused on preserving an original negative or print as a physical artifact to one instead focused on saving a digital work that has no tangible embodiment.
Electronic works are encoded and usually stored on a physical storage devices such as a digital or analog tape. The most obvious impediment to electronic longevity is what this author has termed "the viewing problem" (Besser 2000a). While the default for physical artifacts is to persist (or deteriorate in slow increments), the default for electronic objects is to become inaccessible unless someone takes an immediate pro-active role to save them. Thus, we can discover and study 3,000 year old cave paintings and pottery (even though the pottery may be in shards that we need to piece together). But we're unable to even decipher any of the contents of an electronic file on an 8-inch floppy disk from only 20 years ago.

The problem of digital changes and user expectations

Digital technology and high speed networks are leading to sweeping changes throughout society, and moving image production and distribution are in no way immune to either the technological changes nor to the social expectations that these changes have induced.
Thus far, the most far reaching changes in production have been felt in the arena of special effects. For years most special effects have been done digitally. In the past the completed digital effects were transferred back onto film and intercut with the rest of a production, but as general moving image production itself becomes increasingly digital, this intermediary transfer to film will become far less common.
Small-budget independent productions are increasingly being shot and edited in digital form. According to director Mike Figgis, "there is clearly a technical revolution taking place. You can edit a film on a laptop, and there is the Internet, the streaming and downloading capabilities. These are the technical elements of the revolution" (Silverman 2000). He believes that this is leading to massive changes in the industry, "Like anything, once you open up a system to those outside the tight corps who control it, you get a massive increase in product. You also get a lot more talent exposed to the possibilities of creating something new. I'm really looking forward to that kind of chaos and the results. Ö But the real revolution will come when we challenge what I call our biblical way of making films -- the way we edit, shoot and score our films, which is very stagnant. I hope that young filmmakers will continue to say, 'I don't want to do it like that.' Hopefully, with the new technologies, nothing will stop them" (Silverman 2000).
It is only a matter of time before high-budget productions are entirely shot and edited in digital form. The most talked-about foray into this field is Star Wars Episode II, scheduled for a summer 2002 release. According to George Lucas, "The tests have convinced me that the familiar look and feel of motion picture film are fully present in this digital 24P system, and that the picture quality between the two is indistinguishable on the large screen" (Laguna 2000). According to Jim Morris, president of Lucas Digital, "The image quality of the new Sony camera and the Panavision lenses exceeded our expectations, and really validate the 24P system as a great new tool for moviemaking. All of our hopes about doing digital capture for the big screen have started to be realized" (Laguna 2000). Though most productions don't have the budget of Lucasfilm, it is only a matter of time before further demand for this technology drops the prices enough that digital production becomes commonplace for the studios.
Digital distribution coupled with digital theater projection is not nearly as imminent. The first such distribution was June 6, 2000 when Cisco Systems and Qwest Communications transmitted Fox's animated adventure movie Titan A.E. from Los Angeles to Atlanta. There have been other experiments since and more than 2 dozen theaters worldwide are equipped for just one of several standards for digital projection (Digital Light 2001) and some analysts contend that this number will jump to 500 by the time of the release of Star Wars: Episode II (Laguna 2000),but the process is far from mainstream. Competing standards (NIST 2001) and the large cost of installing digital projection equipment will slow the growth of this type of projection. It is also unclear whether the recent bankruptcy of major theater chains (Loews, United Artists) will slow or accelerate this type of distribution. When we eventually reach the point where digital distribution of commercial releases is widespread, economics will dictate that many of those works will never be converted to film or video. But this is unlikely to happen this decade.
Technological changes have altered users' expectations in a variety of ways. One can make the claim that the time-shifting features of the VCR helped instill a user mindset of viewing a video any time of day or night, and that this in turn created a market for video-on-demand and for cinema multiplexes that staggered starting times so that a particular new release might be seen every half hour.
The WorldWide Web is leading to further expectations of immediacy, as well as increased desires to see both massive amounts of related materials, as well to view material in fragmented ways. The act of "web-surfing" involves a user bouncing from one tangentially related fragment of information to another. Web surfers will seldom read an entire lengthy document online, but will skim part of a document, jump to something related to it and briefly read that, then jump to still another related fragment.
Recent enhanced DVDs appeal to the web-surfer mentality. Adding additional material about the making of the film, interviews with cast and crew, stills from the set, out-takes, and other ancillary materials all appeal to the web-surfer expectation of having a vast array of related primary-source material available. Over time we may very well see a demand for users to just view particular clips (Besser 1994) within a completed movie. And on the horizon is a whole new set of products that involve repurposed clips that we can only begin to imagine. We do know that today's primary multimedia delivery vehicles (both DVDs and the Web) are enhancing user expectations of extensive interactivity.

From saving completed works to managing assets

The digital impact mentioned here is likely to promote widespread changes within the moving image archival community. The increasing amount of material originating in digital form (some of which may never be transferred to film or video), the release of moving image products that contain a variety of ancillary material, the increased focus on fragments that need to be easily found and that sometimes may be repurposed and reused in multiple digital products -- all these elements imply significant changes in practices for moving image archives.
Technological developments have led to a large number of users no longer being satisfied with merely viewing end products. The high demand for additional content implies that some organization needs to supply the ancillary material that helps contextualize the finished product. Interviews, scripts, correspondence, sketches of sets, special effects, out-takes, and even moving images of initial casting calls are all valuable assets that surround a completed work. In the past, only a limited number of this type of material was saved, and often it was saved outside the moving image archive (in records management units, print archives, or special collection libraries). In the future, as new digital products and services emerge, there will be increasing pressure to minimize the dispersal of these assets. And moving image archivists who do not move quickly to widen their areas of responsibility may soon find themselves marginalized and subordinated to digital asset managers.
Archivists need to shift from a paradigm centered around saving a completed work to a new paradigm of saving a wide body of material that contextualizes a work. They also need to proactively seek out material (particularly moving image material) that may today be routinely be thrown away, but in the future may prove historically and/or commercially valuable. And they need to fulfill their traditional role of making sure that this material will persist over time.
Archivist involvement in the stages before the final cut implies new skillsets. Ingesting out-takes means developing new skills for organizing and managing this type of material. And doing a good job of managing special effects data implies understanding how to keep software files accessible over time.
Preserving special effects files may prove to be critically important. Several decades from now, a person looking back on a film like The Matrix will be far less interested in the film as a whole, and much more interested in the special effects and how they were done. Access to the special effects data files is likely to be valuable in understanding the historical development of moving image material, and the final cut on film reveals little of the ground-breaking processes involved.
As we have seen with both the Web and DVDs, there is increasing demand to view material in fragments. This type of fragmented use is a perfect complement to a post-modern era, where mass cultural elements are repeatedly re-contextualized. Promotional units within a studio, advertisers, production companies, and end users all periodically request to see and/or use a particular clip. This implies an increasing need for access at lower levels of granularity than a completed work. Moving image archivists need to prepare themselves for requests at this lower level of granularity, and would do well to follow some of the literature on methods for finding clips that do not rely upon human labor to catalog and index all the sub-parts of a work (Besser 2000b, Turner 1999, Goodrum 1998).
Archivists shifting to articulate an asset management approach can have strategic advantages. Some of the greatest influx of money for preservation in the past 20 years emerged when studios realized that there was an after-market for older films. Today we are living in an age where content repurposing is a driving economic force, and there is high expectation that any given media asset will be used in a variety of secondary multimedia products (from a clip on the Web, to incorporation within a video game, to a variety of DVDs and CD-ROMs, to even including clips of one film within a subsequent film [like The Limey]). Savvy administrators recognize that today's capital investment in adequately preserving and indexing media assets can pay off in long-term repeated use and re-use.
Still, the shift from managing completed works as a whole to managing a range of assets will be a profound one. And much of this shift requires background and knowledge about how to make digital files persist over time.

Problems with Preserving anything Digital

Information encoded and stored in digital form is fragile, but in very different ways than film stock. And though digital storage shares some characteristics with video storage, it is different from that as well. Below we will outline several special problems with preserving works in digital form, but first we will begin with the simplest aspect: the physical storage medium.
Film is a relatively long-lasting storage medium; barring a few exceptions (such as nitrate and Eastmancolor), film stored under proper conditions is stable and relatively long-lasting. Video storage, on the other hand, is unstable. Compared to film, videotapes have a relatively short shelf-life. The physical strata used to store videos decays relatively quickly, and video preservationists recognize that they need to periodically refresh the contents of a videotape by copying it onto another physical strata before the original deteriorates.
Digital storage, like video storage, requires periodic refreshing because the physical storage strata decays. Digital storage offers the illusion that preservation is not a problem because, unlike analog storage formats (such as film and video), a digital copy is ostensibly an exact replica of what was copied (whereas each copy of a film or video loses quality from that of the previous copy).
But though digital refreshing is itself near-lossless, works stored in digital form raise enormous other preservation problems. Chief among these is the problem of rapidly changing file formats -- files encoded in AVI or MPEG-1 or the various flavors of MPEG-2 can be periodically refreshed onto new physical strata, but it is highly unlikely that those formats will be viewable a decade from now. To understand this problem, we need only to turn to recent experience with much simpler word processing documents.
Word processing files (which are primarily ascii text, and thus much simpler formats than moving or even still images) are generally readable for half a dozen years after they are created. But even these word processing formats become inaccessible after a dozen years. Fifteen years ago Wordstar had (by far) the largest market penetration of any word processing program. But few people today can read any of the many millions of Wordstar files, even when those have been transferred onto contemporary computer hard disks. Even today's popular word processing applications (such as Microsoft Word) typically cannot view files created any further back than two previous versions of the same application (and sometimes these still lose important formatting). Image and multimedia formats, lacking an underlying basis of ascii text, pose much greater obsolescence problems, as each format chooses to code image, sound, or control (synching) representation in a different way.
Elsewhere this author has outlined other digital longevity problems such as "the translation problem," "the custodial problem," "the scrambling problem," and "the inter-relational problem." (Besser 2000a) He has also specifically applied these problems to electronic art (Besser forthcoming). All of these are relevant to digital preservation of moving image material. Particularly notable are "the custodial problem " and "the translation problem."
"The custodial problem" focuses upon who should be in charge of making something persist over time. Though we have developed traditions of which organizations (and who within a given organization) should take responsibility for preserving and maintaining various types of analog material (film, video, stills, correspondence, manuscripts, printed matter), no such traditions exist yet for digital material. As a result of this, much current material originating in digital form falls through the cracks, and is unlikely to be accessible to future generations.
For example, print archivists and special collections librarians who aggressively pursue print-based collection development in their particular specialty areas claim that it should be the responsibility of their organizationsí computing staff to pursue collection development of material originating in digital form. Yet those computing staff claim that it should be the subject-matter specialistsí responsibility to pursue collection development of digital materials. Meanwhile, much of this fragile material is not collected at all. Motion picture animation studio archives that have had established procedures for saving sketches and cells typically have no procedure in place for saving the digital files that are now replacing those sketches and cells.
Many moving image archivists feel they have neither the resources nor the technical knowledge to take charge of digital files of moving image materials. They have no money for file-servers and no idea of how to develop a long-term digital migration strategy. So digital moving image files end up either not being collected at all, or they become the responsibility of a department that has not been trained in archival and preservation practices (such as an information technology department or a digital asset management department).
Though at the present time resource allocation and technological skills may force the handling of digital material into another department, this is a dangerous long-term strategy. Archivists have well developed training and skills for handling moving image materials, and these skills are seldom found in staff from other departments. As costs for handling digital materials diminish and as strategies for long-term maintenance of digital files become better known, reasons for handling digital material separately will start to fade, and administrators will begin to realize that digital files of moving images have much more in common with film and video than with word-processing files and databases. At some point, the idea of handling digital moving image files in a separate department will sound as old-fashioned as establishing separate departments for 16mm , 35mm, and cinemascope film formats.
A number of experiments are underway to explore strategies for maintaining digital content over time. We still need to develop guidelines and best practices so that organizations and individuals who want to make the effort to try to make digital information persist will know how to do so.
A key function of archives is in ensuring the authenticity of a work. Print archives do this by amassing "evidence" and by maintaining a "chain of custody" (Council 2000). Film archives follow a variation of this through strategies like identifying the release negative. But when works are subject to repeated acts of "refreshing" as most approaches to digital longevity propose (see section "General Approaches to Digital Preservation"), these traditional ways of ensuring authenticity break down. Files repeatedly copied to new strata face the likelihood that changes will be introduced into these files, and we know little about how to control mutability across repeated "refreshments". This set of problems constitutes "the custodial problem."
Another important issue is how a work translated into new delivery devices changes meaning ("the translation problem"). While a lay person may occasionally confuse the two, people in the cultural community are clear that a photograph or poster of an oil painting is definitely different than the painting itself, and that a video of a motion picture film is not the same as the film. We clearly understand that a reproduction of a work (particularly changing into another format) may convey certain characteristics of that work, but is dramatically different than that work. The faithfulness of the photographic reproduction processes has raised questions about differences between originals and reproductions (Benjamin 1978, Besser 1997, Besser 1987), particularly of photographs. But those of us in the cultural community still recognize that a digitized photograph displayed on a screen is quite different from the paper-based photograph it was digitized from, or that a motion picture film converted and shown on a video screen is quite different from the original film.
Today, most electronic moving image works (both video and digital) are displayed on cathode-ray tube screens (CRTs). With the advent of liquid-crystal and other flat-panel display units, a decade from now CRT screens may be as rare as black and white monitors are today. And fifty years from now it is unlikely that one would be able to even find a working CRT screen. For some electronic works (certainly for artistic ones that concern themselves with the "look" of a CRT), attempting to display that work on a flat-panel screen would result in something that the creator would regard as poor reproduction of his or her work (perhaps akin to a photograph of an oil painting). For one of his pieces that opened in the new Tate Modern Museum, video artist Gary Hill told the museum that they can replace fading CRT screens with other similar-sized CRT screens, but he was adamant that replacing any of them with flat-panel screens would significantly alter the meaning of his work (Laurenson 2000).
Computer-based moving image works are often designed for particular screen dimensions. As screen resolutions get higher, these older works end up looking smaller and smaller on contemporary screens. (For example, a work created to fill a 640X480 screen would take up about 1/3 of a contemporary 1024X768 screen.) This raises issues of how best to display older digital works on newer digital screens. Though there are certainly parallels between this problem and those experienced by film archives wanting to display older films with proper lenses, in appropriate aspect ratios and original frame rates, digital works convey the illusion that one merely needs to play them and they will be displayed appropriately. With traditional media, the separation between the work (stored on film or video) and the display device is clear; with digital media the public often does not understand the separation between the stored work and the display device (particularly since the stored work may be repeatedly copied from device to device or even streamed)." [...]