Preservation of Audiovisual Content
in Files
Richard Wright
SIPAD14, Mexico City, October 2014
preservationguide.co.uk 2Richard Wright
Overview
 digital preservation
 files and formats
 encodings and wrappers
 los...
preservationguide.co.uk 3Richard Wright
Overview -- Part two
 Access: this is the payoff of putting up with all the probl...
preservationguide.co.uk 4Richard Wright
Resources
 AV Digitisation and Digital Preservation TechWatch
Report #02
 https:...
preservationguide.co.uk 5Richard Wright
Strategies for Survival
preservationguide.co.uk 6Richard Wright
Stone, papyrus, film, hard
drive: what’s next?
Medium bits/cm² life, yr
Stone 10 1...
preservationguide.co.uk 7Richard Wright
Infinite storage,
no persistence:
Photo: http://www.flickr.com/photos/chascar/4764...
preservationguide.co.uk 8Richard Wright
Direction of Technology
Storage is a service: PrestoSpace, 2004
A file is a perfor...
preservationguide.co.uk 9Richard Wright
Stages in the life of AV content
 signal: audio from a microphone, video from a
v...
preservationguide.co.uk 10Richard Wright
Three kinds of AV content
 analogue
 digital on shelves
 CD, DVD, Blu-Ray
 au...
preservationguide.co.uk 11Richard Wright
Audiovisual Content is
Special
Technically demanding
Context: use in “scholarly
c...
preservationguide.co.uk 12Richard Wright
Special Technical Issues
 Audiovisual files are not just quantitatively differen...
preservationguide.co.uk 13Richard Wright
Special Contextual Issues
Use in Scholarly Communication:
 Citation
 Quotation
...
preservationguide.co.uk 14Richard Wright
Special Interoperability
Issues
Europeana:
 Harvests OAI-PMH metadata
 Broadcas...
preservationguide.co.uk 15Richard Wright
The time dimension
Europeana has a time dimension – divided into centuries
Audio ...
preservationguide.co.uk 16Richard Wright
preservationguide.co.uk 17Richard Wright
preservationguide.co.uk 18Richard Wright
Three Aspects of
Digital Preservation
 Making analogue content into digital cont...
preservationguide.co.uk 19Richard Wright
Three Aspects of
Digital Preservation
 1- Making analogue content into digital c...
preservationguide.co.uk 20Richard Wright
Three Aspects of
Digital Preservation
 2- Working with digital content (lots of ...
preservationguide.co.uk 21Richard Wright
Three Aspects of
Digital Preservation
 3- Preserving the digital content
 Keepi...
preservationguide.co.uk 22Richard Wright
Files and their formats
 (US) LOC has a guide to their preservation
www.digitalp...
preservationguide.co.uk 23Richard Wright
Digital Library Services
 Enable automation
 Of ingest
 File format identifica...
preservationguide.co.uk 24Richard Wright
Why Automation?
 Portico (electronic document repository) has
ingested 9.1 milli...
preservationguide.co.uk 25Richard Wright
DROID – UK National Archive
DROID (Digital Record Object Identification) is a sof...
preservationguide.co.uk 26Richard Wright
preservationguide.co.uk 27Richard Wright
preservationguide.co.uk 28Richard Wright
preservationguide.co.uk 29Richard Wright
JHOVE: JSTOR/Harvard Object
Validation Environment
JHOVE provides functions to pe...
preservationguide.co.uk 30Richard Wright
National Library of New Zealand Metadata
Extraction Tool
 Purpose: to programmat...
preservationguide.co.uk 31Richard Wright
Architecture
Digital library services are generally:
 open source
 web service ...
preservationguide.co.uk 32Richard Wright
Encodings and Wrappers
 an MP3 file is MP3 encoded audio in an MP3 file
 BUT- M...
preservationguide.co.uk 33Richard Wright
Lossy compression, lossless
compression, uncompressed
 Lossy data reduction shou...
preservationguide.co.uk 34Richard Wright
preservation of complex
objects (art!)
 if you’re given a lossy file, that’s you...
preservationguide.co.uk 35Richard Wright
Lossless “compression”
 For: saves on storage
 but how much is that as % of tot...
preservationguide.co.uk 36Richard Wright
Bit rot – image examples
GIF: 3 bad bytes in 10k BMP: 160 bad bytes in 40k
preservationguide.co.uk 37Richard Wright
File errors and file resilience
 Prof Manfred Thaller, Univ of Cologne and other...
preservationguide.co.uk 38Richard Wright
File Migration Roadmap

Where am I, where do I go next

Audio: only one answer:...
preservationguide.co.uk 39Richard Wright
Video Roadmap

The basic problem: uncompressed video is 200
megabits per second ...
preservationguide.co.uk 40Richard Wright
Video Roadmap
Preservation Roadmap:
Low: VHS, compressed digital DV file, 25 Mb/s...
preservationguide.co.uk 41Richard Wright
Video Roadmap

Much less clear for high definition video

Many production forma...
preservationguide.co.uk 42Richard Wright
Recommended for Video

Professional: MXF; does everything

Alternatives: MOV (Q...
preservationguide.co.uk 43Richard Wright
File Formats for Film

DPX uncompressed, very flexible

DCI DCDM = Digital Cine...
preservationguide.co.uk 44Richard Wright
Migration of File Formats
I s t h e f o r m a t a
p r o b l e m ?
S T A R T H E R...
preservationguide.co.uk 45Richard Wright
Preservation Strategy

Keep what you have as long as it works

Migrate to a new...
preservationguide.co.uk 46Richard Wright
Strategy with Emulation
I s t h e f o r m a t a t
r is k ?
S T A R T H E R E
A r ...
preservationguide.co.uk 47Richard Wright
OAIS (& METS, MODS,
PREMIS …)
preservationguide.co.uk 48Richard Wright
“OAIS and all that” – and how it
applies to audiovisual material, or
doesn’t
 Op...
preservationguide.co.uk 49Richard Wright
OAIS for audiovisual content:
 Some use in US public broadcasting
 Project WNET...
preservationguide.co.uk 50Richard Wright
More on TRAC
 “The Trustworthy Repositories Audit & Certification:
Criteria and ...
preservationguide.co.uk 51Richard Wright
More on TRAC
 The social, political and economic environment of a
Trusted Digita...
preservationguide.co.uk 52Richard Wright
More TRAC
B1 Procedures related to ingest
B2.10 Process for testing understandabi...
preservationguide.co.uk 53Richard Wright
Levels of digital preservation
 NDSA = National Digital Stewardship Alliance
htt...
preservationguide.co.uk 55Richard Wright
Managing Digital Preservation
- a simple model (from Arkivum)
preservationguide.co.uk 56Richard Wright
Digital: the new problems:
 risk goes up as storage cost goes down;
 format obs...
preservationguide.co.uk 57Richard Wright
What will happen to storage:
 Capacity
 Cost
 Usage
 Risk
?
preservationguide.co.uk 58Richard Wright
The Capacity Goes Up
1980 1990 2000 2010
Hard drive storage capacity
1000
10
0.1
...
preservationguide.co.uk 59Richard Wright
Moore’s Law
Originally – complexity of
integrated circuits
doubling every 18 mont...
preservationguide.co.uk 60Richard Wright
The Cost Goes Down
Cost per gigabyte goes down: cost reduction for storage
has be...
preservationguide.co.uk 61Richard Wright
The Usage Goes UP
preservationguide.co.uk 62Richard Wright
The Risk Goes Up Too
Device reliability has increased
– but the number of devices...
preservationguide.co.uk 63Richard Wright
Risk, Devices and Reliability
 Risk of loss of data:
 proportional to number of...
preservationguide.co.uk 64Richard Wright
Risk, Devices and Reliability
 Many more risks besides loss of storage devices
...
preservationguide.co.uk 65Richard Wright
Conclusion:
As storage gets really cheap
… it gets really risky.
preservationguide.co.uk 66Richard Wright
format obsolescence;
general technology
obsolescence;
 OAIS is meant to provide ...
preservationguide.co.uk 67Richard Wright
Survival Strategies: Prevention
of loss
 Where most of the attention (and resear...
preservationguide.co.uk 69Richard Wright
Limits
 Technology: gets better – and worse – at the same
time
 Rights; seconda...
preservationguide.co.uk 70Richard Wright
Limits: Technology
Medium bits/cm² life
Stone 10 10 000
Paper 104
1000
Film 107
1...
preservationguide.co.uk 71Richard Wright
Limits: Rights
 See Nan Rubin paper (IFLA-PAC)
 http://www.ifla.org/files/asset...
preservationguide.co.uk 72Richard Wright
Limits: Access Mechanisms
 Academic use can be an ‘exception’ to copyright
 Aca...
preservationguide.co.uk 73Richard Wright
Limits: Networks and Cost
 Network charges cost more than storage charges in
BBC...
preservationguide.co.uk 74Richard Wright
Four requirements
for sensible access
 Granularity
 Navigation
 Reference and ...
preservationguide.co.uk 75Richard Wright
Granularity - division into
meaningful units
 Keyframes
 Other methods to repre...
preservationguide.co.uk 76Richard Wright
Navigation
 "Click and play" on visual representation of the
meaningful units
preservationguide.co.uk 77Richard Wright
Reference and Citation
 the core requirement for scholarly discourse
 along wit...
preservationguide.co.uk 78Richard Wright
Annotation
 the core requirement for social
web = interactivity
 individual int...
preservationguide.co.uk 79Richard Wright
Limits: who doesn’t have
Internet
Africa check your users
preservationguide.co.uk 80Richard Wright
Managing Digital Preservation
- a simple model (from Arkivum)
preservationguide.co.uk 81Richard Wright
And now:
one PrestoPRIME tool
 A model for storage systems, to calculate
 Cost
...
preservationguide.co.uk 82Richard Wright
preservationguide.co.uk 83Richard Wright
preservationguide.co.uk 84Richard Wright
Storage Systems
HDD in servers
Migration required every 4 years. Running Costs
Ac...
preservationguide.co.uk 85Richard Wright
More Storage Systems
Data tapes in a robot
Migration required every 6 years. Runn...
preservationguide.co.uk 86Richard Wright
preservationguide.co.uk 87Richard Wright
Storage Configuration
Found 3 storage configurations. Add...
Disk with Tape
Syste...
preservationguide.co.uk 88Richard Wright
preservationguide.co.uk 89Richard Wright
File Collections
 Found 1 file collection. Add...
 read-only
 Default File Col...
preservationguide.co.uk 90Richard Wright
preservationguide.co.uk 91Richard Wright
Plans
Found 3 plans. Add...
Disk and Tape edit Delete Evaluate
File Collection: D...
preservationguide.co.uk 92Richard Wright
preservationguide.co.uk 93Richard Wright
preservationguide.co.uk 94Richard Wright
Thank You
 Storage model: http://prestoprime.it-
innovation.soton.ac.uk/planning...
of 92

Preservation content in_files

Digital preservation: storage, risks, risk and cost management -- "fixity and all that"
Published on: Mar 4, 2016
Published in: Technology      
Source: www.slideshare.net


Transcripts - Preservation content in_files

  • 1. Preservation of Audiovisual Content in Files Richard Wright SIPAD14, Mexico City, October 2014
  • 2. preservationguide.co.uk 2Richard Wright Overview  digital preservation  files and formats  encodings and wrappers  lossy compression, lossless compression, uncompressed  “OAIS and all that” – and how it applies to audiovisual material, or doesn’t  the new problems: risk goes up as storage cost goes down; format obsolescence; general technology obsolescence; survival strategies in a digital world
  • 3. preservationguide.co.uk 3Richard Wright Overview -- Part two  Access: this is the payoff of putting up with all the problems of digital technology: instant free global access – to everything! (Many examples given yesterday)  A review of limits to access; limitations on:  what we keep: increase in risk, increase in amount of content, decrease in life of storage  rights; secondary exploitation; public value licensing; legislation  who gets in: mechanisms for access control: identity, authorisation  networks: cost, bandwidth  tools for understanding storage and risks
  • 4. preservationguide.co.uk 4Richard Wright Resources  AV Digitisation and Digital Preservation TechWatch Report #02  https://prestocentre.org/library/resources/av- digitisation-and-digital-preservation-techwatch- report-02  Digitising Contemporary Art D6.2 "Best practices for a digital storage infrastructure for the long-term preservation of digital files" Sofie Laier Henriksen, Wiel Seuskens and Gaby Wijers (LIMA)  //www.dca-project.eu/deliverables
  • 5. preservationguide.co.uk 5Richard Wright Strategies for Survival
  • 6. preservationguide.co.uk 6Richard Wright Stone, papyrus, film, hard drive: what’s next? Medium bits/cm² life, yr Stone 10 10 000 Paper 104 1000 Film 107 100 Disc 1010 10 Each step: 1000 times cheaper, lasts 1/10th as long Soon? Infinite Zero
  • 7. preservationguide.co.uk 7Richard Wright Infinite storage, no persistence: Photo: http://www.flickr.com/photos/chascar/476475563/ The Cloud !
  • 8. preservationguide.co.uk 8Richard Wright Direction of Technology Storage is a service: PrestoSpace, 2004 A file is a performance: PrestoPrime, 2010 2014: Media without media  Using managed services  Managing managed services  Statistics, trust, indemnity  Advantage: storage provided by professionals; archivists can do archiving (producers can produce, curators can curate ...)
  • 9. preservationguide.co.uk 9Richard Wright Stages in the life of AV content  signal: audio from a microphone, video from a video camera  recording of a signal onto a carrier  digitisation of a recording of a signal  digital preservation of the digitisation of a recording of a signal UK Digital Preservation Coalition: Preserving Moving Pictures and Sound (by R Wright) http://www.dpconline.org/advice/technology-watch- reports
  • 10. preservationguide.co.uk 10Richard Wright Three kinds of AV content  analogue  digital on shelves  CD, DVD, Blu-Ray  audio: Minidisc, DAT  video: DV, professional digital videotape formats  preservation (ripping): make a clone (if possible)  there are complications  there are tools: eg DVAnalyzer  http://www.avpreserve.com/avpsresources/tools/  digital in files
  • 11. preservationguide.co.uk 11Richard Wright Audiovisual Content is Special Technically demanding Context: use in “scholarly communication” Interoperability A Matter of Time Wikimedia Common CC licence; author STEINDY
  • 12. preservationguide.co.uk 12Richard Wright Special Technical Issues  Audiovisual files are not just quantitatively different from usual digital library files  Size: 1hr HD video (uncompressed) = 800 GB  Management: storage, movement  Errors: 1 TB = 1012 ; common disk error rates 10-13  They are qualitatively different  Wrappers – Quicktime (MOV), MXF, AVI, ...  Composites: audio, video, subtitles, timecode ...  Encoding and quality management issues
  • 13. preservationguide.co.uk 13Richard Wright Special Contextual Issues Use in Scholarly Communication:  Citation  Quotation  Annotation  Authority / Provenance All our expectations are based on writing, not on spoken word, audio, film or video The record of an event is the written record. Why? Wikimedia Common CC licence; author Piero
  • 14. preservationguide.co.uk 14Richard Wright Special Interoperability Issues Europeana:  Harvests OAI-PMH metadata  Broadcasters never heard of OAI-PMH  OAI never heard of time-based metadata  Storyboard representation (keyframes)  Subtitles  Time code Digital libraries don’t do time-based access – specific case of lack of structured access
  • 15. preservationguide.co.uk 15Richard Wright The time dimension Europeana has a time dimension – divided into centuries Audio and video use edit systems with timelines in seconds, or fractions of a second – and visual representations of content divided into units (of some kind): the storyboard
  • 16. preservationguide.co.uk 16Richard Wright
  • 17. preservationguide.co.uk 17Richard Wright
  • 18. preservationguide.co.uk 18Richard Wright Three Aspects of Digital Preservation  Making analogue content into digital content  Digitisation (covered yesterday)  Working with digital content  Digital workflow and processes  Preserving the digital content  Digital Preservation
  • 19. preservationguide.co.uk 19Richard Wright Three Aspects of Digital Preservation  1- Making analogue content into digital content  Planning  Budget  Workflow  Standards  Rights  Result: lots of files  PrestoSpace information online: //preservationguide.co.uk/RDWiki/  Now: revised for PrestoCentre = //prestocentre.eu/
  • 20. preservationguide.co.uk 20Richard Wright Three Aspects of Digital Preservation  2- Working with digital content (lots of files)  Management  DAM/MAM  Repository  Storage  Metadata  digital library technology  Access  Rights
  • 21. preservationguide.co.uk 21Richard Wright Three Aspects of Digital Preservation  3- Preserving the digital content  Keeping the data ‘forever’  Coping with obsolescence  Migration  Emulation  Standards: “OAIS and all that”  Digital preservation technology  Planning and strategy
  • 22. preservationguide.co.uk 22Richard Wright Files and their formats  (US) LOC has a guide to their preservation www.digitalpreservation.gov/formats/intro/intro.shtml  (UK) National Archive has format registry PRONOM – and they archive software www.nationalarchives.gov.uk/pronom/  (Netherlands) National Library has emulation for DOS, extending life of software (sort of) http://dioscuri.sourceforge.net/  Digital Library technology runs services on files: JHOVE, DROID, metadata extraction
  • 23. preservationguide.co.uk 23Richard Wright Digital Library Services  Enable automation  Of ingest  File format identification DROID, JHOVE  File validation JHOVE  Metadata extraction  National Library of New Zealand  OAI-PMH protocol for metadata harvesting  Of migration  PLANETS ‘preservation planning’ methods
  • 24. preservationguide.co.uk 24Richard Wright Why Automation?  Portico (electronic document repository) has ingested 9.1 million PDFs in a decade  (and 800k had validation errors)  How many files would the BBC send to an asset management system per day, coming from how many different applications?  (1000 files from 100 applications?)  Meaning a million in three years  All of which need ingest, validation, preservation
  • 25. preservationguide.co.uk 25Richard Wright DROID – UK National Archive DROID (Digital Record Object Identification) is a software tool developed by The National Archives to perform automated batch identification of file formats. DROID is designed to meet the fundamental requirement of any digital repository  to be able to identify the precise format of all stored digital objects  and to link that identification to a central registry of technical information about that format and its dependencies. DROID uses internal and external signatures to identify and report the specific file format versions of digital files. These signatures are stored in an XML signature file, generated from information recorded in the PRONOM technical registry. New and updated signatures are regularly added to PRONOM, and DROID can be configured to automatically download updated signature files from the PRONOM website via web services. DROID is a platform-independent Java application, and includes a documented, public API, for ease of integration with other systems.
  • 26. preservationguide.co.uk 26Richard Wright
  • 27. preservationguide.co.uk 27Richard Wright
  • 28. preservationguide.co.uk 28Richard Wright
  • 29. preservationguide.co.uk 29Richard Wright JHOVE: JSTOR/Harvard Object Validation Environment JHOVE provides functions to perform format-specific identification, validation, and characterization of digital objects.  Format identification is the process of determining the format to which a digital object conforms; in other words, it answers the question: "I have a digital object; what format is it?“  Format validation is the process of determining the level of compliance of a digital object to the specification for its purported format, e.g.: "I have an object purportedly of format F; is it?" Format validation: well-formedness and validity. 1. well-formed: it meets the purely syntactic requirements for its format. 2. valid: it is well-formed and it meets additional semantic-level requirements .  Format characterization is the process of determining the format- specific significant properties of an object of a given format, e.g.: "I have an object of format F; what are its salient properties?"
  • 30. preservationguide.co.uk 30Richard Wright National Library of New Zealand Metadata Extraction Tool  Purpose: to programmatically extract preservation metadata from a range of file formats  Initially developed in 2003; open source in 2007.  The Tool builds on the Library's work on digital preservation, and its logical preservation metadata schema. It is designed to:  automatically extracts preservation-related metadata  output that metadata in a standard format (XML)  Supported File Formats: the Metadata Extract Tool includes a number of 'adapters' that extract metadata from specific file types. Extractors are currently provided for:  Images: BMP, GIF, JPEG and TIFF.  Office documents: MS Word (version 2, 6), Word Perfect, Open Office (version 1), MS Works, MS Excel, MS PowerPoint, and PDF.  Audio and Video: WAV and MP3.  Markup languages: HTML and XML
  • 31. preservationguide.co.uk 31Richard Wright Architecture Digital library services are generally:  open source  web service architecture  reliant on metadata standards (schema) to work at all Do audiovisual archives need these services? Can these services work (or be made to work) on professional audiovideo files?
  • 32. preservationguide.co.uk 32Richard Wright Encodings and Wrappers  an MP3 file is MP3 encoded audio in an MP3 file  BUT- MP3 could also be in an AVI file along with video  OR – MP3 could be in an MXF file along with video (and the video could be in various encodings)  Hence: when a file can hold various kinds of encodings, and especially when a file can hold multiple audio and video signals – we call it a wrapper so that we can separate:  the file type (eg AVI, MXF …)  from the encodings of signals inside the wrapper
  • 33. preservationguide.co.uk 33Richard Wright Lossy compression, lossless compression, uncompressed  Lossy data reduction should not be created by the archive  but if you’re given a lossy file, that’s your ‘artefact’  Uncompress and save ‘whole’ when obsolescent  DO NOT recode from one lossy format to another; that becomes a ‘generation loss’  Saving SD video ‘whole’ is cheaper than digibeta!  Saving HD video ‘whole’ may be completely unfeasible for several more years; shame
  • 34. preservationguide.co.uk 34Richard Wright preservation of complex objects (art!)  if you’re given a lossy file, that’s your ‘artefact’  if you’re given a ‘work’ – that’s also your artefact  basic principle – preserve the artefact  complex artefacts may not divide into ‘essence’ and metadata (signals and metadata)  migration becomes less and less satisfactory  emulation (esp multivalent approach) may be much more satisfactory  Institutions need to maintain legacy ‘platforms’ – as KB in The Hague is already doing (DOS)
  • 35. preservationguide.co.uk 35Richard Wright Lossless “compression”  For: saves on storage  but how much is that as % of total dig archive cost?  Against:  adds a layer of complexity in creation (one off)  adds a layer of complexity in playback (forever)  slows down playback  may tie you to proprietary software  or even proprietary hardware!  destroys the error-tolerance of an uncompressed file
  • 36. preservationguide.co.uk 36Richard Wright Bit rot – image examples GIF: 3 bad bytes in 10k BMP: 160 bad bytes in 40k
  • 37. preservationguide.co.uk 37Richard Wright File errors and file resilience  Prof Manfred Thaller, Univ of Cologne and other papers (eg Heydegger,2008)  Example: image file with one bad byte Format Size % of file affected TIFF 10M 0.000 01 JPEG 3.8M 2.1 JP2K 7.3M 17  State of the Art: uncompressed, or inter-frame compression, with fixity check on each frame (AVPS has guidance to fixity checks)
  • 38. preservationguide.co.uk 38Richard Wright File Migration Roadmap  Where am I, where do I go next  Audio: only one answer: uncompressed to .wav file; some options  16-bit bit depth, or could go for “24”  CD sampling rate= 44.1 kHz; or 48 kHz or 96 kHz  BWF = Broadcast Wave Format version of .wav  Strong claim: the numbers representing the uncompressed audio signal will never need to change
  • 39. preservationguide.co.uk 39Richard Wright 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”
  • 40. preservationguide.co.uk 40Richard Wright Video Roadmap Preservation Roadmap: Low: VHS, compressed digital DV file, 25 Mb/s Middle: U-Matic, DV DV file High: BetaSP, Digibeta, uncompressed or other pro formats lossless compressed, (JPEG2000 FFV1)
  • 41. preservationguide.co.uk 41Richard Wright Video Roadmap  Much less clear for high definition video  Many production formats  Various kinds of “HD”  But:  Interlaced video should be saved as interlaced  Saving the 'native format' is ALWAYS good  Saving uncompressed remains a problem
  • 42. preservationguide.co.uk 42Richard Wright Recommended for Video  Professional: MXF; does everything  Alternatives: MOV (Quicktime), AVI  But: AVI does not support timecode
  • 43. preservationguide.co.uk 43Richard Wright File Formats for Film  DPX uncompressed, very flexible  DCI DCDM = Digital Cinema Distribution Master: 2048x1080 (or 4096x2160) only  DCP = Digital Cinema Package = lossy compressed JPEG200; (not for master)  JPEG2000 (lossless); 2:1 data reduction  Various lossy compression formats (avoid!)  And … various wrappers: MXF, AVI ...
  • 44. preservationguide.co.uk 44Richard Wright Migration of File Formats I s t h e f o r m a t a p r o b l e m ? S T A R T H E R E A r c h i v e f o r a f e w y e a r s W h a t c o s t / q u a l i t y / r i s k o p t i o n c a n y o u a f f o r d C o m p r e s s l o s s y Y E S N O U n c o m p r e s sC o m p r e s s l o s s l e s s E N D H E R E ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 a )( 5 b ) ( 5 c )
  • 45. preservationguide.co.uk 45Richard Wright Preservation Strategy  Keep what you have as long as it works  Migrate to a new format when the old format has a problem (usually, obsolete)  Examples: Real Audio, MPEG-1 Video  OR – maybe you can emulate the software needed to use the file, even after standard software no longer works  One emulator: Univ of Liverpool Multivalent Browser
  • 46. preservationguide.co.uk 46Richard Wright Strategy with Emulation I s t h e f o r m a t a t r is k ? S T A R T H E R E A r c h i v e f o r a f e w y e a r s W h a t c o s t / q u a lit y / r is k c a n y o u a f f o r d ? C o m p r e s s lo s s y Y E S N O U n c o m p r e s s C o m p r e s s lo s s le s s E N D H E R EM u lt iv a le n t
  • 47. preservationguide.co.uk 47Richard Wright OAIS (& METS, MODS, PREMIS …)
  • 48. preservationguide.co.uk 48Richard Wright “OAIS and all that” – and how it applies to audiovisual material, or doesn’t  Open Archive Information System is a concept for tightening control over files, so that there is much less risk of their loss  “Trusted Digital Repositories” (TDRs) follow OAIS (and various other principles)  TRAC – methods for evaluation whether a TDR deserves the label ‘trusted’  Much information form DPE = Digital Preservation Europe URL: www.digitalpreservationeurope.eu/
  • 49. preservationguide.co.uk 49Richard Wright OAIS for audiovisual content:  Some use in US public broadcasting  Project WNET (with WGBH and NYU) (closed!)  used Fedora digital repository software  and METS, PREMIS, PBCORE (not MODS)  PrestoPRIME implemented OIAS and other digital preservation technology as a demonstration system  partner: Ex Libris, Rosetta, New Zealand  Many repositories now use OAIS “information packages” – SIP, AIP, DIP; Archivematica is free and open-source  Overall problem: content that is regularly changed
  • 50. preservationguide.co.uk 50Richard Wright More on TRAC  “The Trustworthy Repositories Audit & Certification: Criteria and Checklist (TRAC), is the principle tool used by CRL in its auditing and certification of digital repositories. TRAC criteria measure the ability of a given repository to preserve digital content in a way that serves the repository's stakeholder community.”  “TRAC metrics are based on the ISO 14721:2012 standard. This standard is commonly referred to as the OAIS reference model”  http://www.crl.edu/archiving-preservation/digital- archives/metrics-assessing-and-certifying
  • 51. preservationguide.co.uk 51Richard Wright More on TRAC  The social, political and economic environment of a Trusted Digital Repository  TRAC Criteria Documents A1.2 Contingency plans, succession plans, escrow arrangements (as appropriate) A3.1 Definition of designated community(ies), and policy relating to service levels A3.3 Policies relating to legal permissions A3.5 Policies and procedures relating to feedback A4.3 Financial procedures A5.5 Policies/procedures relating to challenges to rights
  • 52. preservationguide.co.uk 52Richard Wright More TRAC B1 Procedures related to ingest B2.10 Process for testing understandability B4.1 Preservation strategies B4.2 Storage/migration strategies B6.2 Policy for recording access actions B6.4 Policy for access C1.7 Processes for media change C1.8 Change management process C1.9 Critical change test process C1.10 Security update process C2.1 Process to monitor required changes to hardware C2.2 Process to monitor required changes to software C3.4 Disaster plans
  • 53. preservationguide.co.uk 53Richard Wright Levels of digital preservation  NDSA = National Digital Stewardship Alliance http://www.digitalpreservation.gov/ndsa/ www.digitalpreservation.gov/ndsa/activities/levels.html protect know monitor repair  storage, fixity, security, metadata, file formats  nothing specifically about audiovisual issues
  • 54. preservationguide.co.uk 55Richard Wright Managing Digital Preservation - a simple model (from Arkivum)
  • 55. preservationguide.co.uk 56Richard Wright Digital: the new problems:  risk goes up as storage cost goes down;  format obsolescence;  general technology obsolescence;  survival strategies in a digital world
  • 56. preservationguide.co.uk 57Richard Wright What will happen to storage:  Capacity  Cost  Usage  Risk ?
  • 57. preservationguide.co.uk 58Richard Wright The Capacity Goes Up 1980 1990 2000 2010 Hard drive storage capacity 1000 10 0.1 0.001 Gigabytes
  • 58. preservationguide.co.uk 59Richard Wright Moore’s Law Originally – complexity of integrated circuits doubling every 18 month But – memory in general (RAM, disc, tape) has followed the same ‘law’ Fred G Moore
  • 59. preservationguide.co.uk 60Richard Wright The Cost Goes Down Cost per gigabyte goes down: cost reduction for storage has been faster than Moore’s Law since 1990
  • 60. preservationguide.co.uk 61Richard Wright The Usage Goes UP
  • 61. preservationguide.co.uk 62Richard Wright The Risk Goes Up Too Device reliability has increased – but the number of devices in use has greatly increased
  • 62. preservationguide.co.uk 63Richard Wright Risk, Devices and Reliability  Risk of loss of data:  proportional to number of devices  and to the size of the devices (because each holds more data)  and the complexity of storage management (unless somehow complexity can be used to reduce risk)  and … to reliability of individual devices
  • 63. preservationguide.co.uk 64Richard Wright Risk, Devices and Reliability  Many more risks besides loss of storage devices  format obsolescence  IT infrastructure obsolescence  file corruption  system corruption  errors and other human actions  Which all increase in significance (impact) in proportion to the amount of storage in use
  • 64. preservationguide.co.uk 65Richard Wright Conclusion: As storage gets really cheap … it gets really risky.
  • 65. preservationguide.co.uk 66Richard Wright format obsolescence; general technology obsolescence;  OAIS is meant to provide an overall structure that is entirely independent of implementation technology  None of this technology has really been proven!  (and I’m still worried about storage failures and bit rot)  ‘continuous migration’ is one answer to all forms of obsolescence (if always done in time)
  • 66. preservationguide.co.uk 67Richard Wright Survival Strategies: Prevention of loss  Where most of the attention (and research) is directed:  reducing MTBF for devices  making copies !  using storage management layer(s)  introducing virtual storage layer(s)  using Digital Library technology  OAIS ‘packages’  preservation metadata (PREMIS)
  • 67. preservationguide.co.uk 69Richard Wright Limits  Technology: gets better – and worse – at the same time  Rights; secondary exploitation; public value licensing; legislation  Who gets in: mechanisms for access control: identity, authorisation  Networks: cost, bandwidth  Who doesn’t have Internet?
  • 68. preservationguide.co.uk 70Richard Wright Limits: Technology Medium bits/cm² life Stone 10 10 000 Paper 104 1000 Film 107 100 Disc 1010 10 => Each change 1000 times cheaper, but lasts 1/10th as long
  • 69. preservationguide.co.uk 71Richard Wright Limits: Rights  See Nan Rubin paper (IFLA-PAC)  http://www.ifla.org/files/assets/pac/ipn/47-may- 2009.pdf “Not having clear permission to reuse older programs is a primary factor that discourages public television from making an investment in long-term program preservation. Until rights agreements are improved, archival content will remain largely inaccessible.”  BBC Creative Archive – used a version of a Creative Commons licence
  • 70. preservationguide.co.uk 72Richard Wright Limits: Access Mechanisms  Academic use can be an ‘exception’ to copyright  Academic institutions use controlled networks  Shibboleth is an emerging global standard (W3C) for access / identification (in academia)  Who supports identification of the general public?
  • 71. preservationguide.co.uk 73Richard Wright Limits: Networks and Cost  Network charges cost more than storage charges in BBC Open Archive trial  BUT – solved (?) by YouTube
  • 72. preservationguide.co.uk 74Richard Wright Four requirements for sensible access  Granularity  Navigation  Reference and Citation  Annotation
  • 73. preservationguide.co.uk 75Richard Wright Granularity - division into meaningful units  Keyframes  Other methods to represent video  and audio:
  • 74. preservationguide.co.uk 76Richard Wright Navigation  "Click and play" on visual representation of the meaningful units
  • 75. preservationguide.co.uk 77Richard Wright Reference and Citation  the core requirement for scholarly discourse  along with a major change in attitude!  Needs a permanent place for “things to be”  Hence the need for stable audiovisual collections “Hamlet, for example, is comparable to Saxo Grammaticus' Gesta Danorum.[citation needed] King Lear is based on King Leir in Historia Regum Britanniae by Geoffrey of Monmouth, retold in 1587 by Raphael Holinshed.[citation needed] “ wikipedia
  • 76. preservationguide.co.uk 78Richard Wright Annotation  the core requirement for social web = interactivity  individual interacts with content  individuals interact with other individuals
  • 77. preservationguide.co.uk 79Richard Wright Limits: who doesn’t have Internet Africa check your users
  • 78. preservationguide.co.uk 80Richard Wright Managing Digital Preservation - a simple model (from Arkivum)
  • 79. preservationguide.co.uk 81Richard Wright And now: one PrestoPRIME tool  A model for storage systems, to calculate  Cost  Risk  Loss  And compare what-if scenarios  Storage model: http://prestoprime.it- innovation.soton.ac.uk/planning-tool/
  • 80. preservationguide.co.uk 82Richard Wright
  • 81. preservationguide.co.uk 83Richard Wright
  • 82. preservationguide.co.uk 84Richard Wright Storage Systems HDD in servers Migration required every 4 years. Running Costs Access: €0.1 per GB Storage: €1 per GB per year Corruption Rates Access: avg. 1 in 500 files Latent: avg. 1 in 750 files per year HDD on shelves Migration required every 4 years. Running Costs Access: €1 per GB Storage: €0.25 per GB per year Corruption Rates Access: avg. 1 in 100 files Latent: avg. 1 in 500 files per year
  • 83. preservationguide.co.uk 85Richard Wright More Storage Systems Data tapes in a robot Migration required every 6 years. Running Costs Access: €0.2 per GB Storage: €0.4 per GB per year Corruption Rates Access: avg. 1 in 1x104 files Latent: avg. 1 in 1x105 files per year Data tapes on shelves Migration required every 6 years. Running Costs Access: €1 per GB Storage: €0.1 per GB per year Corruption Rates Access: avg. 1 in 1x104 files Latent: avg. 1 in 1x105 files per year
  • 84. preservationguide.co.uk 86Richard Wright
  • 85. preservationguide.co.uk 87Richard Wright Storage Configuration Found 3 storage configurations. Add... Disk with Tape System 1: HDD in servers Files accessed avg of 0.25 times per year, staying constant Scrubbing every 1 year(s) System 2: Data tapes in a robot Files accessed avg of 0 times per year, staying constant Scrubbing every 3 year(s)
  • 86. preservationguide.co.uk 88Richard Wright
  • 87. preservationguide.co.uk 89Richard Wright File Collections  Found 1 file collection. Add...  read-only  Default File Collection  Length of cost/loss projection is 25 year(s). Files  100 thousand initially, staying constant.  Average File Size  25 GB.
  • 88. preservationguide.co.uk 90Richard Wright
  • 89. preservationguide.co.uk 91Richard Wright Plans Found 3 plans. Add... Disk and Tape edit Delete Evaluate File Collection: Default File Collection 25 year lifetime. 100 files, avg. 25 GB in size. Storage Configuration: Disk with Tape Uses HDD in servers and Data tapes in a robot systems.
  • 90. preservationguide.co.uk 92Richard Wright
  • 91. preservationguide.co.uk 93Richard Wright
  • 92. preservationguide.co.uk 94Richard Wright Thank You  Storage model: http://prestoprime.it- innovation.soton.ac.uk/planning-tool/  PrestoCentre prestocentre.eu  Richard Wright preservation.guide@gmail.com preservationguide.co.uk

Related Documents