magnetic videotape recordings: preservation, assessment, and migration

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


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?


Magnetic Media Cross-Section

Polyester

Polyurethane

Back-coat

with magnetic particles and additives

2-5 m

10-40 m


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


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


Agents of Deterioration

• Heat• Light• Excessive Moisture• Extreme Mechanical Stress• Dust


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


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


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.


Format Proliferation

• Reel-to-reel• Cartridge• Cassette

Each requires specific playback machinery and has different qualities


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.


Format Proliferation~over 60 separate formats~


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


http://www.arts.state.tx.us/video/pdf/video.pdf

OBSOLESCENCE

ExtinctCritically endangeredEndangeredThreatenedVulnerableLower risk


SMPTE STANDARDSSociety of Motion Picture and

Television Engineers


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


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”


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.


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


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?


Preservation Priority Surveys

• Host of new tools (see Audio Preservation handouts)

• Needs diagnostic data points


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


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


http://aic.stanford.edu/sg/bpg/annual/v15/bp15-18.html

http://aic.stanford.edu/sg/bpg/annual/v15/bp15-18.html

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


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



A High

B Mod

C Low

A High

A

A

B

B Mod

A

B C Physical Damage

C Low

A

B C


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]


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.)


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


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


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


DIGITAL TAPE FORMATS WITH 4:2:2 SAMPLING

• D1• DCT• DVC Pro• D9• Digital Betacam• HD-Cam• HD-D5• D6


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


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)


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


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


http://aic.stanford.edu/sg/emg/library/

Some Video File Formats

• .mj2• .mov• .avi• .wmv• .vob• .mpg


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


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


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


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


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




http://www.amianet.org/

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


http://www.bavc.org/

http://www.crawford.com/

http://www.safesoundarchive.com/

http://www.scenesavers.com/

http://www.specsbros.com/

http://www.media-matters.net/aboutus.html

An In-House Duplication Rack


$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


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

http://cinema.tisch.nyu.edu/page/miap.html

http://www.eastmanhouse.org/inc/education/selznick_school.php

http://www.eastmanhouse.org/inc/education/selznick_school.php

Thank you!

Sarah Stauderman

Collections Care Manager

Smithsonian Institution Archives

[email protected]


magnetic videotape recordings: preservation, assessment, and migration

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