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Subject: Audio tape and videotape

Audio tape and videotape

From: Jim Lindner <vidipax>
Date: Wednesday, May 6, 1998
Patricia Smith-Hunt <smith [at] oak__cats__ohiou__edu> writes

>Our library expects to receive a fairly sizeable collection of
>audio and video tapes soon and we are making some preliminary
>plans for its preservation and storage. The material is
>probably about 10-15 years old and has been stored in
>basements. These tapes contain scientific data; therefore, a
>faithful reproduction of the original is critical. We have also
>been cautioned about reformatting techniques that may result in
>loss of information due to compression, cleaning up, etc. The
>faculty are very interested in digital migration; however, I
>have not been able to find information that definitively
>supports this approach. Has anyone had experience with
>reformatting audio and/or video tape collects using
>digitization?

There are many different ways to digitize audio and video
information, and so it is important to really understand exactly
what kind of digitization you are contemplating and what the result
will be for your application. We reformat video on a daily basis 24
hours a day, 7 days a week, and normally migrate the source tapes
and film to digital videotape formats as well as an analog format at
the same time. There are several digital videotape formats that are
uncompressed and full resolution that will give an accurate
representation of the source tapes.


For archival purposes we normally recommend composite digital
formats that use no compression--these formats are known as D2 and
D3. Sometimes we migrate using component digital video formats that
have no compression (or little compression) such as D1, D5, or
Digital Betacam. There are several formats that do compress the
video information using "lossy" compression and these formats do
indeed throw out information and for this reason we do not normally
recommend them. The formats that have very heavy compression are
generally less expensive, but in general the machines that provide
high levels of quality and low or no levels of compression a class
of "professional" videotape recorders that are relatively expensive.
The way the information is reformatted is also critical because an
accurate representation takes a great amount of technical skill as
well as a significant amount of equipment other than the recorders
themselves.

Optical media like DVD at this point in time require *very* heavy
compression. While DVD appears to be very useful for access and
other applications, it is probably not an appropriate format for
archival storage applications at the moment.... but this is a fast
moving area. We are currently evaluating providing DVD-R as an
*adjunct* to the other non-compressed options for reformatting in a
high quality manner that we currently offer. Our web site
<URL:http://www.vidipax.com> discusses these topics in some detail
as well as providing links to other sources of information. We also
have a free video format wall chart that lists all the NTSC video
formats as well as providing the characteristics of the formats so
that one can compare the different options. Please email requests
for this chart to my address above.

Jim Lindner
VidiPax
The Magnetic Media Restoration Company
vidipax [at] panix__com
450 West 31 Street - 4th Floor
New York NY 10001
212-563-1999
Fax: 212-563-1994

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                  Conservation DistList Instance 11:90
                  Distributed: Wednesday, May 6, 1998
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Received on Wednesday, 6 May, 1998

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