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Presentation delivered by Sarah Stauderman, Smithsonian Institution Archives' Collection Care Manager, at the Smithsonian Archives Fair on October 22, 2010 in Washington, DC. Highlights basic information you need to know about your videotape collections in order to make good decisions about preserving them.
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MAGNETIC VIDEOTAPE RECORDINGS:
Preservation, Assessment, and Migration
Sarah StaudermanCollections Care Manager
Smithsonian Institution Archives
1Digital Directions, August 18, 2010
Key Concepts for Video Preservation
• Identify Collections – Attributes– Materials – technical issues and connoisseurship– Content
• Identify Preservation Strategy– Storage– Selection through survey and assessment
• Implement Preservation Reformatting– Documentation– Collaboration– Expertise
2Digital Directions, August 18, 2010
Attributes
• What is the videotape format?– What are the known materials for this format type?– Is the format considered a professional, consumer, or
“prosumer” format?
• What is the date of the videotape?• What is the content of the videotape?• What are the known storage needs for this
material?• What is the obsolescence rating for this format?
3Digital Directions, August 18, 2010
Magnetic Media Cross-Section
Polyester
Polyurethane
Back-coat
with magnetic particles and additives
2-5 m
10-40 m
4Digital Directions, August 18, 2010
Magnetic Component
• Gamma Ferric Oxide - stable• Barium Ferrite (BaF) – very stable• Chromium Dioxide (Cr02) – early forms
unstable; later forms stable• Metal Particle (MP) – earliest form
unstable; later forms stable• Metal Evaporated (ME) – unstable
5Digital Directions, August 18, 2010
Videotape Deterioration
• Physical Structure: Base, Binder, Pigment• Binder Failure: “Sticky Shed Syndrome”• Life Expectancy: 10 – 30 years
– “Magnetic Tape Storage and Handling” (1995) Commission on Preservation and Access and National Media Lab
R1-NH-C(=O)-O-R2
6Digital Directions, August 18, 2010
Agents of Deterioration
• Heat• Light• Excessive Moisture• Extreme Mechanical Stress• Dust
7Digital Directions, August 18, 2010
Appropriate Storage for VideotapesISO 18923 and 18933
• 10-year storage: 46°-73°F and 15-50% RH • 50-year storage: 51°F and 50% RH and
pollution controls• Never place magnetic media below 46°F
8Digital Directions, August 18, 2010
Basic Preservation Guidelinesfrom Magnetic Tape Storage and Handling
• Replace tapes every 10-30 years (when 12% of binder hydrolyzed)
• Store at 59°F (+/- 5°) and 40% RH
• Treatment such as baking advocated for damaged tapes
• Visual examination leads to quality of playback diagnosis
• When do you know that 12% has hydrolyzed?
• Why can’t tapes be frozen? (lubricant)
• What are the long-term effects of baking or other?
• No conclusive methods to show correlation of physical state to sticky shed
9Digital Directions, August 18, 2010
Basic Housekeeping
• Dust free• Grounded metal shelves• Upright, like books• Wound (or rewound) position• Remove record tab• Find out what you have – and label it –
before it gets put on a shelf.
10Digital Directions, August 18, 2010
Format Proliferation
• Reel-to-reel• Cartridge• Cassette
Each requires specific playback machinery and has different qualities
11Digital Directions, August 18, 2010
VR - 1000
The VR-1000 was the first videotape recorder ever sold. It achieved its success by separating the “writing speed” (the speed at which information is recorded on the tape) from the tape speed through the use of spinning heads, a principle that has continued in every videotape format to date.
12Digital Directions, August 18, 2010
Format Proliferation~over 60 separate formats~
13Digital Directions, August 18, 2010
Format Identification Guideshttp://videopreservation.stanford.edu/vid_id/
index.html Videotape Identification Guide produced in 1998-99 to help curators, collections managers, and conservators identify formats
http://www.arts.state.tx.us/video/pdf/video.pdf
Texas Commission of the Arts Videotape Identification and Assessment Guide 2004
http://en.wikipedia.org/wiki/Videotape_recorder
14Digital Directions, August 18, 2010
OBSOLESCENCE
ExtinctCritically endangeredEndangeredThreatenedVulnerableLower risk
15Digital Directions, August 18, 2010
SMPTE STANDARDSSociety of Motion Picture and
Television Engineers
16Digital Directions, August 18, 2010
NTSC
• National Television System Committee– Established the specifications for resolution of display
of the video signal on the television picture tube in the United States (used in Canada and Japan too)
– 525 horizontal lines per frame of video– Frame rate is 30 frames per second– ULTIMATE picture quality = 210,000 pixels
• Distinguished from SECAM or PAL– 600 horizontal lines per frame of video– Frame rate is 25 frames per second– ULTIMATE picture quality = 300,000 pixels– Much better color fidelity
17Digital Directions, August 18, 2010
NTSC Composite (or, how to broadcast color on a black-and-white system)
• Color Video Signal (RGB Signal) consisting of red, green, blue
• Color information generates a Luminance Signal (“Y” or black and white) and phase-alternating Chrominance Signal (“C” color information)
• Thus COMPOSITE indicates 2 signals coming from 3 sources
• If information coming from “C” is out-of-phase, can generate major image color shift, thus “never the same color”
18Digital Directions, August 18, 2010
NTSC Component
• Color Component Video exists as three separate electric signals (plus synchronization): Red, Green, Blue.
• Each color signal is processed through its own isolated path.
• Some systems use a Y, R-Y, B-Y configuration in order to eliminate unnecessary color information.
19Digital Directions, August 18, 2010
Analog vs. Digital
ANALOG• Continuous waveform representing the size and shape
of picture information• Can be component or composite
DIGITAL• Video signal exists as a set of numbers representing
analog voltage values• Quality of video is determined by the precision and
frequency of sampling of analog values• Can be component or composite
20Digital Directions, August 18, 2010
Preservation Strategy
• What to Preserve: – Preserve the object, migrate, emulate? Defer action? – Selection
• Why Preserve: Documentary, Intrinsic, Artistic Value?
• How to Preserve: For instance, if choose to migrate In house or outside vendor? What preservation “format”? How to incorporate duplicates into collections?
• For whom: General public through the Internet; lone scholars on-demand; to generate programming?
21Digital Directions, August 18, 2010
Preservation Priority Surveys
• Host of new tools (see Audio Preservation handouts)
• Needs diagnostic data points
22Digital Directions, August 18, 2010
Diagnostic Data Points
• Dust or dirt on container or on item• Wind of the cassette (popping, spoking, etc.)• Presence or absence of record tab (housekeeping)• Anecdotal evidence that a tape brand is poor quality or
aging rapidly• Degree of information on label• Storage history• No strict correlation between physical condition and
playability • Playback issues (skew, tracking, balance)• No easy diagnostic tool forthcoming
23Digital Directions, August 18, 2010
A Preservation Priority Worksheet
• Undergoing the exercise is as important as the methodology
• Uses a matrix to determine priorities• Emphasizes intellectual control and
obsolescence• Based on “An ‘Angels Project’ of Dinosaur
Proportions” http://aic.stanford.edu/sg/bpg/annual/v15/bp15-18.html
24Digital Directions, August 18, 2010
Overview of Survey Tool
I. Identify the Collection – Don’t survey unless content has been determined
II. Value Assessment – Ask multiple colleagues about collections; don’t give all collections a high value
III. Risk Assessment – Condition, Obsolescence, Level of Risk, Master/Element
25Digital Directions, August 18, 2010
CONDITION MATRIX Unstable Materials
A High
B Mod
C Low
A High
A
A
B
B Mod
A
B C Physical Damage
C Low
A
B C
26Digital Directions, August 18, 2010
CONDITION MATRIX Unstable Materials
A High
B Mod
C Low
A High
A
A
B
B Mod
A
B C Physical Damage
C Low
A
B C
27Digital Directions, August 18, 2010
CONDITION MATRIX Unstable Materials
A High
B Mod
C Low
A High
A
A
B
B Mod
A
B C Physical Damage
C Low
A
B C
28Digital Directions, August 18, 2010
CONDITION MATRIX Unstable Materials
A High
B Mod
C Low
A High
A
A
B
B Mod
A
B C Physical Damage
C Low
A
B C
29Digital Directions, August 18, 2010
RESULTS of SURVEY at SI ARCHIVES
• 10% NO NEED [received a low-priority score of 8 or 9 based solely on age of the collection ≤10 years]
• 80% SOME NEED [received a moderate priority score of 4 to 7 based on a combination of age ≥ 10 years and format obsolescence: ¾” U Matic]
• 10% URGENT NEED [received a high-priority score of 1 to 3 based on a combination of age ≥ 20 years and format obsolescence: ½” EIAJ reel-to-reels and 1” SMPTE Type C]
30Digital Directions, August 18, 2010
Reformatting Video
• Preservation Formats– Same or better quality than original– Proven track record of use– Seek the highest sampling and least
compression– Choose reputable technologies and
machineries– Consider purpose of reformatting (for
broadcast, digital asset management, migration, etc.)
31Digital Directions, August 18, 2010
Analog vs. Digital
• Most analog formats are quickly becoming obsolete
• Analog has unacceptable degree of generational loss and poor quality
• Digital tape formats have capture and compression issues
• Digital files have management and expense issues
32Digital Directions, August 18, 2010
Digitization: Ideal Color Sampling
4:4:44 = Luna (brightness, darkness) sampled at every pixel4 = Chroma (Red) sampled every pixel4 = Chroma (Blue) sampled every pixel
1 hour of NTSC analog video 140 GB1 hour of HD video 840 GB
33Digital Directions, August 18, 2010
REALISTIC COLOR SAMPLING
4 : 2 : 2
4 = Luna (brightness, darkness) sampled at every pixel2 = Chroma (Red) sampled every other pixel2 = Chroma (Blue) sampled every other pixel
34Digital Directions, August 18, 2010
DIGITAL TAPE FORMATS WITH 4:2:2 SAMPLING
• D1• DCT• DVC Pro• D9• Digital Betacam• HD-Cam• HD-D5• D6
35Digital Directions, August 18, 2010
COMPRESSION RATIOLossy vs. Lossless
• No compression would be best but is difficult and expensive
• Lossless compression is OK but also difficult and expensive, not “robust” (yet)
• Most Videotape formats and Advanced Television System Committee [ATSC] formats employ compression that is LOSSY
• Compression ratios of 4:1 may be considered OK for archival purposes
36Digital Directions, August 18, 2010
COMPRESSION RATES OF SOME VIDEOTAPE FORMATS
• D1 (no compression; obsolete)• DCT (2:1)• DVC Pro (5:1)• D9 (3.3:1)• Digital Betacam (2.3:1)• HD-Cam (7.1:1)• HD-D5 (4:1)• D6 (no compression; obsolete)
37Digital Directions, August 18, 2010
A Word about DVDs
• Sampling and compression rate uses MPEG-2 or MPEG-4 sampling and compression [encoding]
• 4:2:2 or 4:2:0 sampling• 10:1 or greater approximate compression
ratio• In a VOB container format• About 4.7 GB
38Digital Directions, August 18, 2010
Good-enough Formats• Preservation of Video in the Conservation
Laboratory (PPT)Tim Vitale, June 2005 http://aic.stanford.edu/sg/emg/library/
• Any digital videotape format’s “resolution” is better than your average analog videotape collection and can capture all the information necessary
• Systems using ITU-R.BT601 standard are able to capture on a computer at high resolution and low compression (using MPEG4 compression and .mov codec [Quicktime])
• Cost of loaded system $50-60K
39Digital Directions, August 18, 2010
Some Video File Formats
• .mj2• .mov• .avi• .wmv• .vob• .mpg
40Digital Directions, August 18, 2010
What about PERFECT video duplication?
• Preservation-Worthy Digital Video; or, How to Drive your Library into Chapter 11 (PDF)Jerome McDonough, June 2004 http://cool.conservation-us.org/coolaic/sg/emg/library/pdf/mcdonough/McDonough-EMG2004.pdf
• Placing video onto hard drives or robotic-type systems at the highest sampling rate
41Digital Directions, August 18, 2010
Motion JPEG 2000?• Lossless Video Compression for Archives: Motion
JPEG2k and Other Options Ian Gilmour, Media Consultant, National Film and Sound Archive, Australia and R. Justin Dávila, Technology Consultant, Media Matters LLC January 2006 http://www.media-matters.net/docs/WhitePapers/WPMJ2k.pdf
• An Evaluation of Motion JPEG 2000 for Video Archiving
Glenn Pearson and Michael Gill, National Library of Medicine 2005 http://archive.nlm.nih.gov/pubs/pearson/MJ2_video_archiving.pdf
42Digital Directions, August 18, 2010
A Practical Solution for the Smithsonian Archives (SIA)
• Digital Betacam as a preservation medium• DVDs or VHS as a use copy• Most duplication done by vendor using
specifications written by SIA• Experimenting with SAMMA solo
machinery that places video content onto LTO-3 tapes in JPEG 2000 format
43Digital Directions, August 18, 2010
Reformatting Guidelines
• Document your actions including strategy• Ideally, tapes should be cleaned prior to transfer using a
“buffer-winder” system. Excessive cleaning should be avoided.
• Baking should be avoided as a routine operation, but may be necessary for tapes that show “sticky shed.”
• Tape machines should be immaculately maintained.• Slates, color bars*, and sound tones* should be placed
on new copies to identify the videotape and calibrate it.*indicating calibration occurred prior to transfer
44Digital Directions, August 18, 2010
Reformatting Vendors
Resources• Independent Media Arts Preservation
http://www.imappreserve.org/info_res/services/treatment.html
• Association of Moving Image Archivists (listserv) http://www.amianet.org/
• Local post-production companies
45Digital Directions, August 18, 2010
Reformatting Vendors
• Bay Area Video Coalition http://www.bavc.org/ • Crawford Communications, Inc.
http://www.crawford.com • Safe Sound Archive
http://www.safesoundarchive.com/ • Scene Savers http://www.scenesavers.com• Specs Brothers http://www.specsbros.com/ • SAMMA
http://www.media-matters.net/aboutus.html
46Digital Directions, August 18, 2010
An In-House Duplication Rack
47Digital Directions, August 18, 2010
$40,000 +/-• Equipment rack and shelves $ 2,000• Matrix router for dubbing and monitoring $ 1,500• Audio monitor panel $ 500• Sync Generator $ 500• Hardware, cables, connectors $ 500• Waveform monitor and vectorscope $ 1,500• Timebase Corrector $ 1,000• Betacam SP deck $ 8,000 • 13” Color Monitor $ 1,000• Digital Betacam deck (used) $17,000• Original videotape decks $ 1,000• Engineer to design and put it together $ 2,500
48Digital Directions, August 18, 2010
Plus
Tape stock @ $20 per tape
Cleaning machine(s)
Qualified staff person(s)
NYU Film Preservation Program http://cinema.tisch.nyu.edu/page/miap.html
Selznick School of Film Preservation http://www.eastmanhouse.org/inc/education/selznick_school.php
49Digital Directions, August 18,
2010
Thank you!
Sarah Stauderman
Collections Care Manager
Smithsonian Institution Archives
50Digital Directions, August 18, 2010