Magnetic Videotape Recordings: Preservation, Assessment, and Migration

MAGNETIC VIDEOTAPE RECORDINGS:Preservation, Assessment, and Migration
Sarah Stauderman
Collections Care Manager
Smithsonian Institution Archives
1
Digital 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
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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?
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Magnetic Media Cross-Section
Polyurethane
with magnetic particles and additives
Polyester
Back-coat
2-5 m
10-40 m
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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
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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
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Agents of Deterioration
Heat
Light
Excessive Moisture
Extreme Mechanical Stress
Dust
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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
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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
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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.
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Format Proliferation
Reel-to-reel
Cartridge
Cassette
Each requires specific playback machinery and has different qualities
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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.
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Format Proliferation~over 60 separate formats~
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Format Identification Guides
http://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
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OBSOLESCENCE
ExtinctCritically endangeredEndangeredThreatenedVulnerableLower risk
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SMPTE STANDARDSSociety of Motion Picture and Television Engineers
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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
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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”
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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.
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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
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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?
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Preservation Priority Surveys
Host of new tools (see Audio Preservation handouts)
Needs diagnostic data points
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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
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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
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Overview of Survey Tool
Identify the Collection – Don’tsurvey unless content has been determined
Value Assessment – Ask multiple colleagues about collections; don’t give all collections a high value
Risk Assessment – Condition, Obsolescence, Level of Risk, Master/Element
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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]
30

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.)
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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
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Digitization: Ideal Color Sampling
4:4:4
4 = Luna (brightness, darkness) sampled at every pixel
4 = Chroma (Red) sampled every pixel
4 = Chroma (Blue) sampled every pixel
1 hour of NTSC analog video 140 GB
1 hour of HD video 840 GB
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REALISTIC COLOR SAMPLING
4 : 2 : 2
4 = Luna (brightness, darkness) sampled at every pixel
2 = Chroma (Red) sampled every other pixel
2 = Chroma (Blue) sampled every other pixel
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DIGITAL TAPE FORMATS WITH 4:2:2 SAMPLING
D1
DCT
DVC Pro
D9
Digital Betacam
HD-Cam
HD-D5
D6
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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
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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)
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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
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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
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Some Video File Formats
.mj2
.mov
.avi
.wmv
.vob
.mpg
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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
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Motion JPEG 2000?
Lossless Video Compression for Archives: Motion JPEG2k and Other OptionsIan 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
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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
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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
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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
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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
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An In-House Duplication Rack
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$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
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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
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Thank you!
Sarah Stauderman
Collections Care Manager
Smithsonian Institution Archives
staudermans@si.edu
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Magnetic Videotape Recordings: Preservation, Assessment, and Migration

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