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Digitisation: Best Practice and Standards

Digitisation: Best Practice and Standards. Sexto Seminario Internacional de Archivos Sonoros y Audiovisuales MIÉRCOLES 25 DE JUNIO DE 2014 MESA 5: La digitalización de los acervos Richard Wright. Best Practice? Examples. Columbia University Library:

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Digitisation: Best Practice and Standards

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  1. Digitisation: Best Practice and Standards SextoSeminarioInternacional de ArchivosSonoros y Audiovisuales MIÉRCOLES 25 DE JUNIO DE 2014 MESA 5: La digitalización de los acervos Richard Wright

  2. Best Practice? Examples • Columbia University Library: http://library.columbia.edu/services/preservation/audio.html “Audiotapes are preserved by re-recording original recordings onto reel-to-reel tape, following nationally recognized preservation practices and guidelines; “

  3. Columbia Univ. Library • “Analog copies, carefully made and properly stored, are considered nationally to be the best medium for long-term preservation of sound recordings.” • “...into the future, when digital technology has progressed to new levels of accuracy, we will still have the option to create new digital versions from the full continuum of sound.”

  4. Columbia Univ. Library • “It is clear that digital copies are the better option for access and use. CDs suffer much less from wear and tear during use than do reel-to-reel or cassette tapes.” • ... “Finally, high-quality CD-Rs are a stable medium with a good life expectancy.”

  5. BBC Archive • 1997: vinegar syndrome in acetate magnetic sound tracks (sepmags) • Took decision to digitise to CD (with pulses to mark sprocket holes) • AND – to make new polyester analogue copies • By 2001 – use of film viewing declined almost to zero; polyester copies almost never used!

  6. British Library Sound Archive • 1980s- off-air recording of radio broadcasts • Decided to ‘go digital’ – very few options (before CD-R, in the days of 5 MB hard drives) • Chose Sony PCM-F1 (betamax videotape) • 15 years later- a struggle to migrate off this format

  7. British Film Institute • Oral history recordings, mainly on cassette • CopyiedtoBetaSP videotape (usingonlythe audio tracks) – becausetheyhadBetaSP !

  8. BBC Archive • Spent ten years copying analogue video tape to Panasonic D3 format • Because D3 was the agreed production format in the BBC • After 2004, D3 obsolete; tapes had to be migrated (to files on LTO data tape) • Problems finding enough equipment and “head life”

  9. INA (Paris) • Late 1990’s: early adopter of datatape (before LTO) • Early adopter of Sony Petasite tape library and SAIT helical-scan datatape • Many problems, ended up migrating to a different technology • Eventually migrating again to LTO MANY archives are on their 2nd or 3rd tape library technology

  10. Photographical Collections • Early 1990s, many professional users of Kodak Photo-CD, Picture CD formats “Keep your memories safe for generations. Preserving your favorite pictures is easy with a KODAK Picture CD.” http://wwwuk.kodak.com/global/en/consumer/kiosk/kioskProducts.jhtml?pq-path=2301249#tab=tab11 Proprietary encoding and storage formats on Photo-CD; all have had to be migrated

  11. Magneto-Optical Media • Plasmon – UDO discs guaranteed for 50 years • Drives were promised that would continue to read the discs • Company folded 2008, with 6000 customers • But – assets bought by Alliance Storage Technologies, Inc. in 2009 • My conclusion: money was lost, but data was not !

  12. Academy of Motion Picture Arts and Sciences (AMPAS) • 2007: “digital 12 times more expensivethan film” • Quoted in NY Times – and justabouteverywhere • “the report’s startling bottom line: To store a digital master record of a movie costs about $12,514 a year, versus the $1,059 it costs to keep a conventional film master.”

  13. AMPAS AMPAS estimation of digital costs for a century: • Find cost in 2005/6 • Multiply by 100 AMPAS: $500 per terabyte per year for near-line data tape storage 2014 cost for Amazon Glacier: $120/TB/yr (and dropping) 3) AMPAS film-in-storage costs did NOT include any provision for access

  14. Who can you trust? • IASA, AMIA, ARSC ... Professional bodies • PrestoCentre prestocentre.eu • Library of Congress www.digitalpreservation.gov • Fonoteca MX, Fonoteca CH, Mediathek AU, Phonogrammarchiv AU, British Library ... • AVPreservewww.avpreserve.com • Other experts – if you know how they know what they claim to know!

  15. Best Practice: Audio • Digitise uncompressed for preservation • MP3 or other compressed formats for access • Lossless compression (eg FLAC) is just a good (in quality) but adds complexity and risks, but saves storage • Save as a WAV file • Best practice: with Broadcast Wave Format metadata

  16. Best Practice: Video (SD) • Digitise according to SDI (serial digital interface) standard (ITU Recc 601) • Which is 200 megabits/sec for SD • Save uncompressed • Or lossless compressed: JPEG2000 or FFV1 • Twenty others: Wikipedia list • Wrapper: MXF, MOV=Quicktime), AVI, MKV=Matroska

  17. Video Roadmap • The basic problem: uncompressed video is 200 megabits per second = 100 gigabytes per hour • VHS quality is roughly 1 megabit/sec (AVC = H.264 = MPEG-4) • DVD quality is roughly 5 megabits/sec (MPEG-2) • So: hard to justify saving poor-quality video as uncompressed video at 200 Mb/s • Compromise: “temporary archiving” in a compressed format “for a few years” • Recommended: DV (25 Mb/s)

  18. Best Practice: Video (HD) • HD is already digital! • Very rare to capture it lossless • So: 1) save what you get 2) Consider also converting to a standard format (recommended: 400 mb/s) • Same wrappers as for SD: MXF MOV MKV AVI

  19. Best Practice: Film Film is exceptional !! Recommended minimum digitisation standards: • 16mm ‘telerecordings’ – HD = 1K sampling • Other 16mm: 2K • 35mm: 4k Critical issue is the ‘bit depth’ – video is only 8 to 10 bits; film can be 14 to 16 bit range Minimum: 14-bit linear, 10-bit log scale B&G report: “Film Scanning Considerations”

  20. Film “Packages” • DPX uncompressed, very flexible, 1 file/frame; no sound • DCI DCDM = Digital Cinema Distribution Master: 2048x1080 (or 4096x2160) only • DCP = Digital Cinema Packaging = lossy compressed JPEG200 • DCDM and DCP use MXF wrapper for images

  21. What about metadata? • Technical • Descriptive • Preservation • Embedded • Requires a lot of attention • Metadata work should be integrated in a digitisation workflow • Metadata handling a major issue in a digital repository workflow

  22. OAIS and metadata

  23. Thank You Preservation Guide preservationguide.co.uk PrestoCentre prestocentre.eu Richard Wright preservation.guide@gmail.com

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