Selecting a Video Digitisation System

Last updated: 27 January 2009
Published in: Digitising analogue media |
Tags: analogue collections | business & community engagement | digitisation | video |

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This document looks at a number of configurations of equipment which can be used to digitise analogue videotapes. This document is intended to be of use to staff engaged in the digitisation of analogue video, whether dealing with only a few or a few hundred tapes.

Introduction

The conversion of an analogue video collection into a digital one holds many potential benefits. It allows older materials to be revitalised, the content becoming a valuable and dynamic resource for users. The newly digitised video collection can be delivered in many different ways (for example; mobile devices, the Internet, via social networking sites or hosted an institution's intranet) and so keep pace with the expectations of collection users.
As can be imagined, the creation of such dynamic resources from potentially fragile analogue videotapes is time consuming and requires careful planning. This document reflects current best practice for setting up a video digitisation suite.

Options when digitising analogue videotape

Digitising materials to computer hard drives has many advantages and is rapidly becoming a standard approach. Once a video is held as a digital file on a computer it is possible to run automated error checking or metadata gathering, grant instant access and easily transcode to other formats suited to a wide range of delivery technologies (see below). However, digitising to a computer hard drive is not the only option. Let's begin by taking a look at some of the others.

Analogue videotape to DVD-video

Videotapes can be digitally copied directly to DVD (Digital Versatile Disc). This approach does not involve a computer at all and is achieved by connecting an analogue video player (a VHS deck for instance) directly to a set-top (domestic style) DVD-recorder, often via a single SCART cable. While this approach is a relatively quick and easy way of making a digital copy of an analogue video (if original videotapes are in good condition) the advantages are often seen to be outweighed by the disadvantages.

Advantages

• Can be carried out by a member of staff who is comparatively unfamiliar with the technology involved
• DVD-video discs are a very common and non-proprietary format (i.e. not supported by only a single manufacturer)

• DVD disc and authoring equipment are inexpensive

Disadvantages

• The quality of the DVD-video copy may be insufficient to meet defined quality control benchmarks
• Optical discs such as DVD may suffer from condition problems which makes them useable in the mid to long term
• In order to generate further copies a computer must be used or the tape replayed and recaptured
  Converting the content of the DVD-video for other methods of delivery is complex and requires a computer and a skilled operator
• These factors mean DVD-videos are an excellent format for local delivery, but are not commonly used as a format for storage or preservation.

Analogue videotape to digital videotape

Many formats of digital videotape now exist and are largely replacing older analogue formats such as VHS for the recoding of new footage. The most common consumer digital videotape format is the mini-DV tape. Several professional digital videotapes are also in common use such as Digital Betacam or ‘Digibeta', a format most often associated with TV news production. Copying an older collection of analogue videotapes to these more contemporary digital videotape formats certainly does have some benefits but the technique seems to be becoming generally less popular.

Advantages

• The contents of tapes can be very accessed in a very simple way, by simply loading the tape into a player and pressing ‘play'
• Quality can be expected to be far higher than the result of the ‘direct to DVD-video recorder' route (mentioned above) though not as good as digitising to a computer hard drive*

Disadvantages

• Physical condition problems similar to those seen in older analogue videotape formats can manifest over the long term
• In order to create further digital copies either two player/recorder decks or a computer system must be used
• As with all tape formats (analogue or digital) instant access to any part of the video data is not possible
• Formats are often proprietary (the property of a single manufacturer) and continuing support is not guaranteed in the long-term
• Storage on digital videotape can prove prohibitively expensive
• These issues, coupled with falling hard drive costs, have made copying analogue videotapes to digital videotapes less popular.

*The exception is the digital videotape format D5 which holds very high quality, uncompressed video. However D5 is not in common usage and in terms of costs per hour of video stored is many times greater than holding the same quality footage on a computer hard drive.

High-end automated video digitisation systems

Major audiovisual and film archives, primarily in the US have worked together with engineers in order to develop automated video digitisation systems. Although in the early stages these systems can transport analogue videotapes via robot, clean, play, digitise, error check, transcode and produce a metadata record for a videotape, all largely unsupervised. Such systems are currently out of the price range of modestly funded digitisation projects, being more suited to large-scale, national institutions which aim to digitise many thousands of videotapes.

Advantages

• High quality digital video and high quality metadata is automatically produced
• Largely automatic, needing little human input
• Extremely quick and efficient

 Disadvantages

•  Out of the price range of most institutions
• Exceptions still require human input
• Often only a single system can be purchased due to cost. This means there is no backup in case of major malfunction
• Support for some systems is not available outside the US

All of these automated systems work differently but each is essentially an analogue videotape to computer hard drive system. As such, the process carried out is simply an automated version to that described below.

Analogue videotape to computer hard drive

This method of digitisation involves the use of a desktop computer-based system to convert an analogue video signal into a digital one. The digital data is then stored on a computer hard drive as a digital video file. This approach is rapidly becoming the standard approach for the archival community as it can output the highest quality digital video files currently possible.

Advantages

• Achieves the highest quality digital video currently possible
• Once on the hard drive the digital video files are available for instant access automated checking processes
• Files are easy converted to other formats (including DVD-video and output to any digital video format if required) using only software
• Hard drive storage is now very low cost and prices constantly fall. The digitisation system too, is increasingly affordable
• Hard drive technology is very common, robust and non-proprietary. Low costs allow for the large, high quality video files to be in duplicate
• Hard drives can be removed quickly and easily from the host computer and stored on shelves with little or no environmental controls measures

Disadvantages

• Staff require an understanding of IT and audiovisual technologies
• Current hard drives contain a spinning disc; this technology is likely to be replaced by solid state (flash drive) technology over the next few years. Solid state is likely to be more robust and even better suited to storing digital video data. However, this is not necessarily a problem as files stored on currently available hard drives can easily be copied onto new solid state drives as they become affordable

A typical analogue videotape to computer hard drive system is looked at in detail in the JISC Digital Media document Equipping a Video Digitisation System.

The importance of technical support

Whichever method is chosen, it is important to secure technical support. Internal institutional support such as IT, library or archival services should be coupled wherever possible with manufacturer's warrantees. These can be extended for a number of years for a small extra cost. Upgrading a computer, for instance by adding an internal analogue to digital ‘capture card', does not usually invalidate a manufacturer's warranty but all conditions should be checked carefully before purchase. Reconditioned playback equipment accompanied by a guarantee may cost a little more, but the extra cost is typically well worth paying.
Time frames for replace or repair should be obtained in writing if possible. Digitisation systems are often constructed in duplicate, even triplicate in order to ensure equipment malfunction does not endanger the progress of the project.

Conclusion

Choosing a method for digitisation can be complex and when making your decision, many factors must be taken into account. Your project or collection will undoubtedly have some very unique aspects which mean the workflow adopted by no single precedent project is entirely applicable. In the end the method is likely to be a compromise.
JISC Digital Media offer a helpdesk service which can offer detailed and tailored advice on each aspect of your video digitisation process from conception to completion.

Last updated: 27 January 2009
Published in: Digitising analogue media |
Tags: analogue collections | business & community engagement | digitisation | video |

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