Introduction

DVCAM is a professional-quality variation of the DV video encoding that was introduced by Sony in 1996. DVCAM also refers to video tape recorders and DV and MiniDV videocassettes that are designed to support the DVCAM video recording specification. DVCAM uses the same tape width and compression scheme as DV but increases the track pitch from 10 microns to 15 microns. The recording speed of DVCAM is also significantly higher than DV cassettes. DVCAM recordings have improved colour rendition and robustness, employ “locked audio” tracks, and are well suited for linear editing environments. The DVCAM format was primarily used in professional markets for electronic news gathering, cable television, documentaries and other long form video production.

Identification

Physical Characteristics

Technical Characteristics

Technical standards

1. Society for Motion Picture Technical Engineers (SMPTE) standard for television 314M Data structure for DV-based audio, data and compressed video – 25 and 50 MB/s. The differences between IEC 61834-5 and SMPTE 314M are shown in Annex A of SMPTE 314M.

Storage

Types of damage and deterioration

Binder deterioration

Description

Commonly known as "sticky shed syndrome." Affected records will have a visible gummy or powdery residue on the surface of the tape. This can damage both the recorded material and playback equipment. Back-coated tapes are most affected by this type of deterioration. 

Cause

Polyester urethane is prone to moisture absorption which can cause the molecular structure of the binder to break down. This process is accelerated by high temperature and high humidity.

Remedy

Environmental conditioning: Moving the tape to a controlled storage environment (40°C / 20 to 25% Relative Humidity) may reverse the affects of hydrolysis over time.

Baking: Holding the tape at an elevated temperature (45°C to 55°C) for a brief period of time (up to 36 hours) can temporarily remove moisture and allow normal playback for a period of one to two weeks. Tapes should not be rewound before baking. 

Drop-out

Description

A brief signal loss caused by a tape head clog, missing magnetic oxide particles, tape defect, or debris on the tape or machine. These factors can reduce head-to-tape spacing and result in the appearance of white spots or streaks on playback. Multiple drop-outs per frame will result in a snowy appearance. 

Cause

Tapes kept in dusty conditions will accumulate particulate matter, increasing the risk of drop-out. 

Remedy

Flaking/missing magnetic oxide particles are an indication of tape deterioration. This type of drop-out cannot be corrected physically. 

Mould

Description

Active mould is generally moist while dormant mould is dry and dusty. Mould growths may be white, black, brown or mustard-coloured and usually have a pattered, fuzzy, or thread-like appearance. Mould can cause permanent damage to tapes over time if not removed. Fungus and mould is also a significant health hazard and affected materials should be handled using gloves and masks. 

Cause

Storing tapes at high temperature and relative humidity levels can facilitate the growth of mould. 

Remedy

Mouldy tapes should be isolated from unaffected materials to prevent cross contamination. Store tapes at a temperature of 24°C in an environment with effective air circulation and less than 50% Relative Humidity. Loose mold can be vacuumed from the tape pack and then the tape should be treated with an appropriate fungicide.  

Stretching and breaking

Cause

Stretching and breaking of video tape usually results from improper handling or use of playback equipment.  

Remedy

Stretching can distort the tape signal however data can usually be recovered (with a decrease in signal quality). 

Accidental recording

Description

Camera operators can accidentally record over pre-existing footage

Cause 

Tape is set to "record mode" when it is inserted into camera or deck

Remedy

Ensure tape is set to "safe mode" before inserting into camera or deck.

Risk assessment

HIGH RISK

1. Digital video material stored on magnetic videotape is considered to be at high-risk of loss or degradation.
   
   

   1. Polyester base film used in videotape is considered very stable.

   2. Other components of the videotape, including the binder, are considerably less stable and are more likely to be the cause of degradation.

   3. Format obsolesce, including lack of well-functioning playback equipment poses an equal or even greater risk than degradation, even with higher quality formats such as Digital Betacam
      
      

2. Archivists should appraise or reappraise digital video material stored on magnetic tape to determine the nature and significance of video elements contained on the tape. See Section 5 of the University Archives Procedure Manual for guidance on appraising sound recordings and moving images.
   
   

3. The archival appraisal should determine whether the video elements have sufficient archival value to justify reformatting and long-term preservation as digital video files.

Related resources

Digitization Handbook:

• Section 9.0 - Outsourced digitization of audiovisual items
• Appendix C - Technical specifications for moving images

University Archives Procedure Manual

• Section 5 - Archival Appraisal - Archival appraisal of sound recordings and moving images

Technology Watch

• Technical overview of digital video systems

Further Reading

Visit the /wiki/spaces/ALC/overview for further reading on /wiki/spaces/ALC/pages/1891631115. 

References

AMIA. "Video Preservation Factsheets." Accessed December 10, 2020. 

Bensinger, Charles. "Chapter 6: All about videotape." In The Video Guide, Second Edition, 71-75. Santa Barbara, California: Video-Info Publications, 1981. 

Bogart, John Van. "What Can Go Wrong With Magnetic Media?" In Magnetic Tape Storage and Handling: A Guide for Libraries and Archives. Washington, DC: The Commission on Preservation and Access, 1995. 

Casey, Mike. "FACET: Format characteristics and preservation problems." Bloomington, IN: Indiana University, 2007. 

Gibson, Gerald. D. "Magnetic tape deterioration: recognition, recovery and prevention." Paper presented at the IASA Conference, Perugia, August 26, 1996.

Jimenez, Mona and Liss Platt. "Videotape Identification and Assessment Guide." Texas Commission on the Arts. 2004. 

MediaCollege.com. "The DVCAM Format." Accessed February 3, 2021. 

Museum of Obsolete Media. "DVCAM (1996 – )." Accessed February 3, 2021. 

PCMag. "DVCAM." Accessed February 3, 2021. 

Preservation Self Assessment Program. "Videotape: DVCAM." University of Illinois at Urbana-Champaign. Accessed February 3, 2021. 

WDVA. "Do DV Formats Mystify You?" 2004. 

Wheeler, Jim. "Videotape preservation handbook." 2002. 

Wilt, Adam J. "The DV, DVCAM & DVCPRO Formats: The DV formats tabulated." August 28, 2005. 

Wilt, Adam J. "The DV, DVCAM & DVCPRO Formats." July 16, 2006. 

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