A PROPOSED STRATEGY FOR THE AUSTIN HISTORY CENTER VIDEO COLLECTION Prepared by John Schooley

Transcription

1 A U S T I N H I S T O R Y C E N T E R VIDEO DIGITIZATION AND DIGITAL ASSET MANAGEMENT: INITIAL STEPS A PROPOSED STRATEGY FOR THE AUSTIN HISTORY CENTER VIDEO COLLECTION Prepared by John Schooley 810 G U A D A L U P E A U S T I N, 0 T X

2 V I D E O D I G I T I Z AT I O N A N D D I G I TA L A S S E T M A N AG E M E N T P L A N : I N I T I A L S T E P S A PROPOSED STRATEGY FOR THE AUSTIN HISTORY CENTER VIDEO COLLECTION EXECUTIVE SUMMARY The Austin History Center (AHC) video collection contains approximately 93,000 hours of footage. This video is on various tape formats, but the majority is recorded on ¾ U-Matic and standard VHS tapes. Both of these formats are obsolete, and are subject to various forms of deterioration such as binder hydrolysis and remanence decay. Finding functioning playback equipment for these formats will grow increasingly difficult. Digitizing as much of this footage as possible is essential due to the limited lifespan of the analog sources. Because of the large amount of footage and the limited time, staffing, and funding available, systematic digitization of the entire collection is impossible. A curatorial approach, making an effort to digitize the most unique, endangered, or historically important content first, is the only realistic option. In the absence of archival standards for video digitization, a common sense approach maximizing the available resources is the best course of action. The resolution of U-Matic and VHS tapes is low, so smaller file formats such as.dv would be more appropriate containers for this video, rather than lossless high definition video files. If the resolution of the original image is only 330x480, using a format with a higher resolution such as HD (1920x1080) would only increase file sizes while providing no additional data, resolution, or picture quality. Storage needs for.dv files are substantially lower than for HD, and with 6TB hard drives now selling for retail prices of $100 per terabyte and below, storage of large numbers of video files is now a realistic option even with limited resources. Emphasis should be placed on digitization in the short term, rather than accessibility. Given the large number of variations currently in use for digital video on the web, the likelihood of changes to the web presence of the City of Austin and the AHC, and the eventual rollout of html5, the landscape for online video is rapidly changing. Time spent preparing derivative files, which may shortly become obsolete, or burning DVDs for the reading room, which may never be requested, could be better spent capturing as many hours of video as possible. Derivative files for web use, and DVD copies for reading room access, can be created later on an as-needed basis. As for the long-term possibilities for access, various platforms to preserve, catalog, and access an institution's AV collections can be explored while initial efforts at digitization are being undertaken. The total number of videos in the collection is large, and the idea of having to have a complete cataloging, metadata, and storage plan for over 90,000 hours of footage before beginning any work is daunting. However, due to limitations of time and staffing, even being extremely optimistic about the speed with which video can be digitized, for the first several years of the digitization effort the total number of files to be managed will be quite low. A wait-and-see attitude can be adopted regarding organization and accessibility while changes in the marketplace regarding digital video play out. 1

3 This assessment will begin with a rough inventory of the amount of footage in the AHC holdings, and then outline the risks video formats face regarding deterioration. It will then examine technical considerations for digital files. It will summarize the issues with different platforms, file formats, and codecs, and issues of how much storage space will be necessary. Finally, some general recommendations are suggested about how to proceed with the digitization of the AHC s video holdings. 2

4 TABLE OF CONTENTS EXECUTIVE SUMMARY...1 TABLE OF CONTENTS...3 SIZE AND SCOPE OF CURRENT COLLECTION...4 Tape Formats and Sizes... 4 Estimated hours of footage... 4 TAPE DETERIORATION...5 Binder Hydrolysis... 5 Magnetic Remanence Decay... 6 Overall Risk for Professional Formats... 6 Risks for VHS Tape... 6 Risks for Playback Equipment... 7 Conclusions... 7 OPTIONS FOR DIGITIZATION AND STORAGE...7 Technical Considerations... 7 Formats and Codecs... 8 Master Files... 8 Storage Requirements Robustness of Data RECOMMENDATIONS Triage Metadata Accessibility Conclusion APPENDIX BIBLIOGRAPHY

5 SIZE AND SCOPE OF CURRENT COLLECTION TAPE FORMATS AND SIZES The AHC video collection contains 13 different video formats. Of these, VHS and ¾ U-Matic are the most numerous, with DV Cam a distant third. The other formats are present, but in minimal quantities (See Table 6, Appendix, for a list of all formats present). ESTIMATED HOURS OF FOOTAGE By doing a rough count of numbers of tapes multiplied by a rough estimate of hours of footage per tape, we can arrive at an approximate estimate of the number of hours of footage in AHC holdings. VHS tapes are by far the most numerous format. Footage of City Council meetings and the meetings of various boards and commissions make up a significant portion of these tapes. Nearly equal in number are the VHS tapes of newscasts supplied by the service Teleclip. Council meetings can run as long as six hours, while boards and commissions are often shorter. An estimate of four hours per tape is approximate. Teleclip tapes also run approximately four hours per tape. Using this average of 4 hours per tape, the AHC has approximately 53,000 hours of City Council, board, and commission meetings and 40,000 hours of Teleclip footage on VHS tape. The next most numerous format in the AHC video holdings is of ¾ U-Matic tapes, the most common professional format. The U-Matic footage at the AHC is primarily from the Austin Music Network, with small numbers of miscellaneous tapes from non-music Austin public access programming. The AMN footage consists of two subgroups - a small group of edited master tapes of AMN programs, averaging about an hour in length; and a larger group of tapes of single video clips of individual songs which are shorter in duration, usually consisting of one or a handful of songs. The AMN master tapes consist of approximately 500 hours of footage, and represent unique footage that is unlikely to exist elsewhere. The single video clips consist of approximately 360 hours of footage. Some of the clips are of local artists, while some are of major-label acts that may not be unique to the AHC collection. While the number of hours of footage on these tapes is lower than on the master tapes, there are a greater number of individual tapes due to the fact that most of these tapes contain only short clips of between one and six songs. While the AMN edited masters are almost all on ¾ U-Matic tapes, the single video clips are about 85% U-Matic and 15% DV Cam. While this represents the bulk of the AHC video holdings, there are also a minimal amount of footage on Betacam, Hi8, Digital8, and MiniDV formats. 4

6 To summarize AHC video holdings, we have approximately 93,000 hours of footage mostly on two formats; VHS and U-Matic (see Table 1). Table 1: Summary of AHC holdings: COA meeting footage on VHS: Teleclip footage of newscasts on VHS: AMN edited masters on ¾ U-Matic: AMN single video clips on ¾ U-Matic and DV Cam: Total: 53,000 hours 40,000 hours 500 hours 360 hours 93,860 hours TAPE DETERIORATION 1 Since the videotape recorder was first marketed commercially in the 1950s, there have been at least 11 different kinds of professional video recording technologies. Each of these so-called legacy formats had its own uniquely engineered type of videotape. No matter what the format, all of these types of tape shared the same basic chemical and electromagnetic characteristics. The principal scientific research on videotape decay has identified two main determinates of tape life: binder hydrolysis and magnetic remanence decay. BINDER HYDROLYSIS Binder hydrolysis occurs when the binder that holds the magnetized metal particles that contain the data on the videotape absorbs water molecules from the air and beings to deteriorate. As the binder absorbs moisture, its underlying molecular structure is gradually weakened, and it begins to separate from the substrate. This effect is known as binder shed or sticky shed. When binder shed occurs, the encoded magnetic particulate embedded in the binder is irretrievably lost, causing dropouts, color loss, and a decrease in signal to noise. Binder shed manifests itself as a fine powder and/or a sticky residue, which can gum up playback equipment. (See Table 7: Average Age of Tape Formats and Risk of Hydrolysis, Appendix) 1 Most of the information for this section, including the charts, was taken from the 2009 paper Causes and Management of Videotape Decay by Richard Keatinge. 5

7 MAGNETIC REMANENCE DECAY The ability of particulate to hold a magnetic charge decays over time. This signal deterioration is called magnetic remanence decay. It results in a reduction in the clarity and volume of sound, and a reduction in picture hue and color saturation. (See Table 8 for a detailed list of the risks of remanence decay across all formats) OVERALL RISK FOR PROFESSIONAL FORMATS The chart below outlines the overall risk to the various videotape formats. It should be noted that ¾ U-matic tape, which makes up the majority of AHC holdings of unique material that is not City Council or board and commission meetings, is classified as high risk. Also of note is that while the AHC collection has only a small amount of footage on Betacam, it is considered a very high risk format, prone to both binder hydrolysis and remanence decay. Table 2 outlines the risk across all formats. Table 2: Overall Risk Levels for Video Formats Format Hydrolysis Risk Remanence Risk Overall Risk Betacam High High Very High M2 High High Very High 2 Quad High Low High ¾ U-matic High Low High 1 Type C High Low High Betacam SP Medium Medium Medium D1 Medium Low Medium D2 Medium Medium Medium D3 Medium Medium Medium Digital Betacam Low Low Low RISKS FOR VHS TAPE VHS tape, the most common consumer format, is also subject to binder hydrolysis and remenance decay. Unfortunately, there have been no conclusive scientific studies determining the useful life of consumer-grade VHS tape. A survey of the literature shows guesses anywhere from a decade to 25 years. While VHS has proven to be relatively stable in appropriate storage conditions, it was intended 6

8 as a consumer format and not as a long-term archival storage medium. The oldest VHS tapes in the AHC collection date from the mid-1980 s, which already puts them well past their expected lifespan. Currently, ¾ U-matic tape appears to be more endangered than consumer grade VHS tape, but all video tapes will need to be migrated to digital formats at some point in order to preserve their contents. RISKS FOR PLAYBACK EQUIPMENT ¾ U-matic According to one of the few studies of the longevity of audio and video equipment, the median lifespan for a 3/4 U-matic Video Cassette was estimated at 7.5 years. 2 This study was conducted in 1986, and production of U-matic decks ceased in the early 1990s. Any U-matic tape decks still in use are on borrowed time. VHS The final major Hollywood motion picture to be released on VHS was in 2005, manufacturing of commercial VHS tapes in the U.S. ceased in 2008, and the last standalone JVC VHS-only unit was produced JVC and other manufacturers still produce combination VHS/DVD decks, but given the decline of the format, it is unknown how long this will be the case. CONCLUSIONS All the footage in the AHC collection is at risk, though Betacam and U-Matic footage is the most endangered. Since the most unique and interesting footage in the collection is contained on these formats, they should be given priority for digitization over VHS and other formats. OPTIONS FOR DIGITIZATION AND STORAGE TECHNICAL CONSIDERATIONS There are currently no archival standards for videotape digitization and storage. While there are archival standards for digitized audio files in the form of the 96/24 broadcast wave file, there is no similar agreed-upon non-proprietary file standard for video. Instead there are competing proprietary file formats, codecs, and software. Storage poses a problem because video files can be quite large in comparison to other types of data files. 2 Post, Richard, Longevity and depreciation of audiovisual equipment, TechTrends, , Springer Boston, Volume: 32 Issue: 6 p

9 There are many competing video editing platforms, at least 40 at most recent count. 3 Adobe Premiere, Sony Vegas, Avid Media Composer, and Apple Final Cut Pro being among the most widely used. All of these competing programs use proprietary file types. The AHC already has an Apple digital video workstation, so even if the decision has already been made regarding what program to use, how best to save the digitized material is problematic. In an archival context, we are concerned not just with current utility but also with long-term storage and access. Settling on one set of criteria when the marketplace is so fragmented could backfire in the long term. FORMATS AND CODECS In addition to the chaotic state of the marketplace, things are further complicated by the complex nature of video file formats. Most video files consist of two different elements: the container, and the codec(s) used inside that container. The container describes the structure of the file: where the various pieces are stored, how they are interleaved, and which codecs are used by which pieces. It may specify an audio codec as well as video. A codec ("coder/decoder" or compressor/decompressor ) is a way of encoding audio or video into a stream of bytes. To make matters more confusing, some names, such as "mpeg-4, describe both a codec and a container, so it's not always clear from context which is being used. You could have a movie encoded with an mpeg-4 codec inside an.avi container, for example, or a movie encoded with the Sorenson codec inside an mpeg-4 container. 4 So, the question becomes - out of the 40-odd competing software platforms, each offering different file format and codec variations, which should the AHC chose for its digital video? The AHC has already purchased a Mac with imovie and Final Cut Pro, so the question of which editing platform to use is decided. The format in which to store the digitized video is still an open question, however. QuickTime is the container used by Apple in Final Cut Pro, not to be confused with other files that are QuickTime-compatible formats. Examples of QuickTime-compatible file formats include AIFF, MP3, MPEG, WAVE, JPEG, and TIFF, just to name a few. A QuickTime movie file uses a.mov file extension. QuickTime is not itself a codec, but rather has the ability to present images and sound stored with a number of codecs. Within the QuickTime wrapper, there can be different codecs, all designed with editors in mind rather than archivists, and all with varying pros and cons. MASTER FILES Archivists strive to avoid altering original documents, so capturing VHS using an uncompressed HD file format as the master file sounds like the proper archival thing to do. For film, which has different properties than video, using a higher-resolution file does indeed provide additional image detail. However, in the case of video it does not improve picture quality or capture any additional information, but only takes up additional disc space without providing additional data. In fact, higher- 3 Wikipedia has a detailed page outlining the differences between 40 currently competing video editing software programs: 4 This was very difficult for me to sort out. I took most of this explanation here from this web page, which attempts to provide a simplified guide to video codecs and formats: 8

10 definition transfers can introduce digital artifacts into the picture that can make the digital version look worse than the VHS original. Unlike film, which is an analog visual source comparable in some ways to an analog audio signal, video images consist of a finite amount of information that higherresolution file formats cannot improve upon. On a VHS and U-Matic tape, the horizontal resolution is 170 lines per scanline, and the vertical resolution (the number of scanlines) is the same as the respective analog TV standard (575 for PAL or 486 for NTSC). In modern-day digital terminology, VHS is roughly equivalent to 333x480 pixels luma and 40x480 chroma resolutions (333x480 pixels=159,840 pixels or 0.16MP (1/6 of a Megapixel)). 5 In general, shorthand for VHS resolution is 330x480 (250 lines). Even the highest-resolution VHS variant, Super-VHS, has a resolution of only 420x480. DVD, by contrast, has a resolution of , full resolution on a 16x9 HD screen is 1920x1080, and the newly proposed UHDTV format (Ultra High Definition Television, the equivalent of an Imax film) has a resolution of To use paper-based material as a metaphor, think about if you had one archives box filled with typed pages of paper. This box represents the information contained in the original VHS tape. Even if you were to build a storage space the size of the Astrodome, you still only have one box of material. You would just be taking up more space to store it. Using uncompressed video files to store material from VHS tape is the same idea - if you only have 330x480 worth of data, using a file with the capacity to store 1920x1080 or even only takes up more space without providing any benefits. Table 3 compares the resolution of various analog and digital formats. Table 3: Video Resolution 6 Analog and early digital : Video CD : U-matic, Betamax, VHS, Video : Super Betamax, Betacam (pro) : LaserDisc, Super VHS, Hi : Analog broadcast : Enhanced Definition Betamax 5 From the Wikipedia entry on VHS: 6 From the Wikipedia entry on video resolution: 9

11 Digital : D-VHS, DVD, minidv, Digital8, Digital Betacam (pro) : Widescreen DVD (anamorphic) : D-VHS, HD DVD, Blu-ray, HDV (minidv) : HDV (minidv) : HDV (minidv), AVCHD, HD DVD, Blu-ray, HDCAM SR (pro) : 2K Digital Cinema : 4K Digital Cinema : UHDTV Knowing all this, we can start to get an idea of what sort of file formats to settle on. Using a format with the capacity to capture in HD, such as H.264/MPEG-4 Part 10 or AVC (the standard for Blu-ray) is unnecessary. With HD, The data rates are large, and the quality isn t any better than a lossless compression. 7 A lower resolution format, such as.dv, has enough capacity (720x480) to capture all information contained in VHS tape (330x480) without loss, while taking up significantly less storage space. Another consideration is the ability of competing formats to be read by different platforms. The.avi and.dv file formats can cross platforms easily, for example, while the H.264 format is used primarily with Avid Media Composer. H.264 is not able to play nice with Final Cut Pro, and has to be converted to be read by FCP. 8 STORAGE REQUIREMENTS Choosing to store digitally captured VHS in uncompressed files takes up significant space. One hour of uncompressed digital video footage would require 94 gigabytes per hour, and one hour of HDTV footage would require 834 GB. Standard definition digital video, with a capacity to record in 720x480 resolution (well above the 330x480 required by VHS), by contrast, requires only 12 GB/hr. 7 Adobe Systems, Inc. "DV Compression Primer." adobe.com n_primer.pdf (accessed April 30, 2011) 8 See some video editing forums for discussion here: and here: 10

12 This is another argument in favor of using a format such as.dv instead of an uncompressed format. Table 4 shows the number of GB needed for one hour of footage using these different file formats. Table 4: Storage Requirements SD (standard definition) digital video (720x480) SD analog video converted to uncompressed digital video HDTV (1440x1080) 12 Gb/hr 94Gb/hr 834 Gb/hr In selecting the proper file format for video storage at the AHC, file sizes are a major consideration. Given the massive size of uncompressed video files, compression of the video data is a necessity. However, in the archival field, compression is generally frowned upon, because it implies that some aspect of the original video is being lost. In reality, the resolution of U-Matic and VHS recordings is so low compared to the resolution of current video formats, that digitizing video from these older formats in an uncompressed file is unnecessary. It merely increases the file size without providing any additional image quality. Nothing is lost by using a compressed file format for these recordings, and storage space is saved. Given our estimate of 500 hours of footage for the edited AMN masters, using a standard definition digital format such as.dv would require 6000 GB of storage space, or about 6 terabytes. 6TB hard drives have dropped significantly in price in recent years. A 6TB drive can be purchased for around $600.00, with drives as large at 16TB available for a few thousand dollars, and storage prices continue to fall. To store 500 hours of uncompressed digital video would require nearly 50 terabytes of space, and would present significant costs in terms of time spent waiting for these massive files to convert, open, download, or export. Table 5 illustrates the amount of disk space needed to store 500 hours of footage using these various formats. Table 5: Storage Requirements for 500 hours of video footage File Type GB/hr Disk Space SD (standard definition) digital video (720x480) 12 Gb/hr 6 TB SD analog converted to uncompressed digital video 94Gb/hr 50 TB HDTV (1440x1080) 834 Gb/hr 417 TB 11

13 ROBUSTNESS OF DATA There is some concern that compressed file formats are more susceptible to data corruption, or bit rot, than uncompressed files. There have been few studies exploring the issue of data corruption in video files. Recent studies 9 examining image files like.jpg or.bmp have revealed better performance for uncompressed data files, but also showed that some compressed formats performed better than uncompressed formats. One study found that the MPEG-2 codec is significantly more resilient to bit errors than H.264 but that the codecs don't behave very well in the case of bit errors. 10 In the absence of conclusive data dealing with video file formats, no firm conclusions can be drawn. The situation for video files is the same as with any other digital file format. In general, there is no perfectly safe storage format for video or any other digital file, and some data corruption may (or may not) be inevitable. There is danger not only from the file formats themselves, but also from the means used to store the files. Tape drives such as LTO5 have been shown to be more resilient than hard drives, but they are also significantly more expensive. Backup copies on DVD may not be any more robust than copies saved to hard drive in the long term. Safety of data can be increased by making as many copies, backed up as frequently, on as robust a format, as budgetary constraints allow. Recommendations for the longest-lived preservation format include printing digital bits onto polyester film stock, a solution that is probably impractical for most archives. An ideal but expensive approach would be multiple automatic LTO5 tape backup drives. A lower cost approach would be multiple copies on servers, shelved hard drives, and DVDs. 11 RECOMMENDATIONS TRIAGE Given that the video formats in the AHC holdings are all in danger of deterioration, and that finding and maintaining functional players for these materials will become increasingly difficult, it is imperative that these materials begin to be digitized as soon as possible. Because digitization capture must take place in real time, with additional time included for setup, metadata entry, waiting for files to export and finalize, editing around dropped tape segments, etc., it may take around 3 hours to digitize a single hour of video. Using this 3/1 ratio, in an idealized world with a staff member devoted solely to digitizing video 40 hours a week for a full year (taking no sick days, holidays, or other days off) only 693 hours of footage could be digitized. Even at this generous rate, digitizing the entire AHC video collection would take over one hundred years! 9 Heydegger, V (2009) Just One Bit in a Million: On the Effects of Data Corruption in Files. Research and Advanced Technology for Digital Libraries, ECDL 2009, LNCS (Podgorny and Klima 2009) 11 Addis, M., Wright, R. and Weerakkody, R. (2010) DIGITAL PRESERVATION STRATEGIES FOR AV CONTENT. In: 2010 Conference of the International Broadcasting Convention (IBC 2010), 9-14 September,

14 Given that the AHC is unlikely to add additional staff, that current staff will have to deal with other job duties, and that shorter clips such as music videos would still require time spent on setup and metadata entry (making them slower going than longer tapes), a realistic goal would be around 3-5 hours of footage digitized per week. At this rate, digitizing the entire AHC video collection would take well over 300 years. Given the size of the AHC video collection and the lack of resources available for digitization, there is simply no way that all, or even a significant amount, of the AHC video collection will ever be digitized. Facing this dilemma, the only solution is to carefully select which footage will be saved. Triage of some sort is the only solution available to us. In deciding which tapes to digitize, factors such as uniqueness of the material, adherence to the AHC collection policy, amount of deterioration present on the tapes themselves, and others must be taken into account. The recommendation is that a short list of 100 or so tapes be created, representing the most unique or endangered footage in the collection. Priority should be given to the digitization of these tapes. As these most endangered tapes are digitized, different strategies for metadata, storage, and access can be explored. It is unrealistic to attempt to devise a complete and comprehensive digitization plan from the outset, especially when current staff is largely unfamiliar with the digitization process and will have to learn what works by trial and error. METADATA The amount of metadata permitted in.dv files is limited. However, a separate database could be created to the exact specifications of the AHC, including the fields deemed most necessary, and as much detail as needed. Other video archives, such as The Texas Archive of the Moving Image, utilize a separate database for their metadata and could provide a model for constructing a database for the AHC video collection. Using a separate database is recommended because there yet exists no archival standard for video metadata, and a separate database will allow easier conversion if best practices for video metadata are agreed upon in the future. If all metadata is entered only in a separate database it might also speed up processing time for digital video, because entering metadata in video files tends to be more time consuming that entering the same information in regular databases which are designed for rapid data entry and organization. It is recommended that a unique identifier be assigned to each physical tape digitized, with the same number being used as the basis for the number of the digital file. Since no archival standards yet exist for video digitization, the file naming convention best practices for audio files described in the report Sound Directions: Best Practices for Audio Preservation could be substituted. This convention takes the following form for audio files, which can easily be transposed to video. For example, the Archives of Traditional Music at IU Bloomington uses the following format: atm_67934_ot290_010101_pres_ wav The elements of the file name are broken down as follows: unit_collectionid_sourceobjectid_physicalsequenceindicator_fileuse_signalprocessingflag_date.fileextension unit = atm (Archives of Traditional Music) collectionid = shortened ATM accession number 13

15 sourceobjectid = ATM shelf number physicalsequenceindicator = identification of what part of the source recording is represented by the file fileuse = the role that the file plays within the unit. signalprocessingflag = identification that the file was signal processed date = year, month, day using the ISO 8601 standard fileextension = extension that identifies the type of file, automatically placed at the end by software While not all of these designations are applicable to video, the Sound Directions guidelines can at least provide a starting point for developing a functional video file naming convention for the AHC. Again, consultation with other archives such as TAMI can be helpful in constructing conventions for file naming, database construction, and what categories of metadata should be recorded. ACCESSIBILITY One of the many benefits of digital video technology is that it allows video footage to be posted online, where it can be accessed by anyone at anytime. There are various platforms already on the market to preserve, catalog and access an institution's AV collections. One of these platforms, Glifos, is currently used by the Texas Archive of the Moving Image. A ballpark figure for setup, licensing, and support of Glifos is around $5000. Unfortunately, the increased opportunity for access is undermined by both copyright and technical considerations. For the purposes of the AHC, posting many of the videos in the AHC collection online may not be possible due to copyright restrictions. And given the ever-evolving nature of digital video, any encoding of videos for the web may quickly become obsolete (with widespread adoption of html5, for example). It may not be worth the time to creative derivative versions, for web or other uses, of every video as they are digitized, because: 1. The standards for web video may change, and quickly. Widespread changes to web video will occur with the increased adoption of html5. A year from now, the landscape will look significantly different as WebM (an audio-video format designed to provide a royalty-free, open video compression format for use with HTML5 video.) is implemented in multiple browsers, those browsers ship non-experimental WebM-enabled versions, and users upgrade to those new versions. 2. Creating derivative versions of video files is time consuming, and adding this step will reduce the total number of hours of footage that can be captured. 3. The AHC collection is unknown and uncataloged. The public has no way to know what to request access to, and currently no way to view it online anyway. 4. Derivative files for web use, or burned DVDs for access, can be created as-needed. 14

16 As the tapes in the AHC collection are all in danger of deteriorating, digitization should be the priority. Exactly how these digital files will be made accessible can be determined later, as html5 is still under development and what changes this will create in online video is unknown. In the meantime, deteriorating tapes can be digitized, and individual access copies can be created as requested if needed. With the City of Austin planning a citywide website re-design in the near future, and given the fastchanging nature of computer and digital video technology, spending too much time worrying about how to make the files accessible at some point in the future may be pointless if the original video is not preserved now. CONCLUSION Given the large number of hours of footage in the AHC collection, the small amount of staff time available, the inexperience of the available staff in handling large-scale digitization projects, and the confusion and lack of archival standards for video file formats, a more small-scale, learn as you go approach is recommended. Emphasis should be placed on capturing unique video footage before tape deterioration renders the footage unplayable, using the most appropriate file types to preserve adequate image quality without wasting digital storage space on unnecessary uncompressed file formats, and using a flexible approach in deciding on necessary metadata and access standards. 15

17 APPENDIX Table 6: Video Formats Present in the AHC Collection Beta original consumer format, now obsolete. VHS most common consumer format. 3/4 U-Matic original industrial/professional format. 3/4 U-Matic mini cassette. 3/4 SP - higher grade tape and recording qualities requiring SP player. 1 Reel to Reel tape - professional format, now obsolete. 2 Reel to Reel tape - highest quality TV format before Betacam, now obsolete. Betacam High-speed higher quality professional tape, the industry standard before digital tape. 8mm consumer format, more compact than VHS. Hi8 higher quality audio and video recording than 8mm. Digital 8 - the digital version of 8mm tape. DVCAM The latest professional digital format. MiniDV Smaller DVCAM tape. Table 7: Average Age of Tape Formats and Risk of Hydrolysis Format Years Manufactured Average Age Risk of Hydrolysis Quad High ¾ U-Matic High 1 Type C High Betacam High 16

18 M High Betacam SP Medium D Medium D Medium D Medium Digital Betacam 1995-Present 7 Low Table 8: Risk of Remanence Decay Format Particulate Type Avg. Age Stability Risk Betacam Chromium Dioxide 25 Unstable High M2 Metal Particle 23 Unstable High Betacam SP Metal Particle 19 Unstable Medium D2 Metal Particle 18 Unstable Medium D3 Metal Particle 18 Unstable Medium 2 Quad Iron Oxide 43 Stable Low ¾ U-matic Iron Oxide 30 Stable Low 1 Type C Co-Modified Iron Oxide 25 Stable Low D1 Co-Modified Iron Oxide 19 Stable Low Digital Betacam Reformulated Metal Particle 7 Stable Low 17

19 BIBLIOGRAPHY Addis, M., Wright, R. and Weerakkody, R. (2010) Digital Preservation Strategies for AV Content. In: 2010 Conference of the International Broadcasting Convention (IBC 2010), 9-14 September, 2010 Adobe Systems, Inc. "DV Compression Primer." adobe.com. (2004). n_primer.pdf (accessed April 30, 2011) Casey, Mike & Bruce Gordon (2007). Sound directions: Best practices for audio preservation. Bloomington, IN & Cambridge, MA: Indiana University & Harvard University. Online. Comparison of Video Editing Software, Wikipedia article, (accessed April 30, 2011) H.264 playback problems, online forum discussion, Nov 29, 2007, (accessed April 30, 2011) H.264 Workflow, online forum discussion, Mar 15, 2011, (accessed April 30, 2011) Heydegger, V (2009) Just One Bit in a Million: On the Effects of Data Corruption in Files. Research and Advanced Technology for Digital Libraries, ECDL 2009, LNCS 5714 VHS, Wikipedia article, (accessed April 30, 2011) Keating, Richard Causes and Management of Videotape Decay, online white paper, (accessed April 30, 2011) Peck, Akanna, Digital Video Formats, online article, (accessed April 30, 2011) Podgorny, Radek, and Milos Klima. "Bit Error Resilience of MPEG-2 and H.264 Video Compression Codecs." IEEE, Post, Richard, Longevity and depreciation of audiovisual equipment, TechTrends, , Springer Boston, Volume: 32 Issue: 6 p12-14, 18