Guideline
Guidelines for Audio and Audiovisual Recording in the South Pacific
by Edgar Waters
Foreword
The initial impetus for the preparation of these guidelines came from
the National Library of Australia's involvement with the Australian South
Pacific Cultures Fund (being represented on its advisory committee) and from
the Library's own interest in the countries of the South Pacific in terms of
both collection building and provision of assistance aimed at developing
library and information service infrastructures. The ASPCF funds a large number
of projects concerned with capturing and preserving cultural activities, using
audio and audiovisual recording techniques. At a recent meeting of the
committee it was agreed that execution of many of these projects might benefit
substantially from advice in the form of a set of guidelines written with local
conditions in mind and covering matters such as choice of equipment and options
for ensuring some degree of longevity of the resulting record.
The Library undertook the job, and subsequently commissioned Dr Edgar Waters, an experienced oral historian and folklorist, to write the guidelines. Prepared in consultation with Kevin Bradley, Manager of the Library's Sound Preservation and Technical Services, the result is a readable and practical handbook, free of jargon, that can be distributed to ASPCF applicants and to other field workers needing guidance on the equipment best suited to their purposes and budgets. Although written primarily with the climatic and economic conditions of the South Pacific in mind, the guidelines have applicability in other developing regions. Publication has been funded by the International Relations Branch of the National Library of Australia, as part of its Regional Cooperation Program.
1. General Information on Audio and Audiovisual Recording
1.1 Introduction
1.1.1. The phonograph was the first machine for recording and reproducing (playing back) sound; it came into use about 120 years ago. Cinematography was the first method of recording and reproducing images in movement ('moving pictures', 'the movies'); it came into use about 100 years ago. Methods of both audio (sound) and audiovisual (sight and sound) recording and reproduction were constantly improved during the first half of the twentieth century. (The term 'audiovisual' is used here to refer to cinematographic film and video cassette tapes. It is used as a matter of convenience only, and it should be noted that many archivists use the term in a different way.)
1.1.2. A period of rapid change and improvement in the technology of sound recording and reproduction began shortly after the end of the Second World War. Big changes in methods of audiovisual recording and reproduction began a little later. Changes occur more and more frequently. Entertainment radio, television, cinema and what is called the 'home entertainment industry is big business, and the big electronics companies spend a lot of money developing new techniques. New machines using these new techniques are constantly coming onto the market. If users do not buy them in large numbers, the manufacturers stop making them. If they do buy them in large numbers, costs come down.
1.2 Audio
1.2.1. In the 1950s, the long-playing gramophone record (LP) became the favoured form for the reproduction of high quality (high-fidelity, hi-fi) sound recording. It has largely been replaced by the compact disc (CD). Machines for playing compact disc are fairly cheap and widely used. Machines for recording onto compact disc are coming into use in professional sound recording studios, but they are not likely to be used outside professional studios in the near future. (A form called the minidisc has been developed, and has desirable features. But at present the minidisc recorder is much more expensive than other recorders which give recordings of similar quality and which are just as easy to use. The digital compact cassette recorder does not seem to have interested many users in other words, not many have been sold and it seems unlikely to come into general use.)
1.2.2. The new sound recording technologies of the second half of this century began with the introduction of magnetic sound recording. Magnetic sound recording, using spools of wire, began in the 1930s. The first magnetic sound recorders became available for general sale soon after the end of the Second World War. Spools of wire were replaced by reels of plastic with a coating of some material that could be magnetised. Three kinds of magnetic tape sound recorder are in wide use today. These are, in the order in which they were developed and came onto the market:
- the open-reel recorder (also called reel-to-reel recorder);
- the compact cassette recorder (sometimes called the Philips cassette recorder because engineers working for the Philips company played an important part in developing it); and
- the DAT (digital audio tape) recorder.
1.3 Audiovisual
1.3.1 Moving pictures intended to be shown ('screened') in cinemas originally consisted of images only ('silent movies'); music was often played as an accompaniment in the cinema during the screening, usually on piano or some kind of organ. 'Talking pictures' were introduced in the 1920s. The images were photographed ('shot', 'filmed') by cinecameras using film 35mm wide. The sound was recorded on separate machines. The finished moving picture had the recorded sound added to it in photographic form, in a strip along one side of the film. (So we speak of 'the soundtrack' of a moving picture.) Colour film for cinecameras was introduced during the 1930s and 1940s, and became common in the second half of the century. Cinecameras using 35mm film are still in general use for producing 'feature films'. Cinecameras using 16mm film are often used by documentary filmmakers. The 35mm cameras used in film studios are large, heavy, and require a mains electricity supply and machines to move them around. The 16mm cameras used by documentary filmmakers are small enough and light enough to be carried by one person, and used while being held in the hands (though it is heavy work), and can be operated from a battery power supply. The sound recording is still done on a separate machine, and a photographic soundtrack added ('married') to the images produced on the film at a later stage, as with 35mm film. There are portable machines (projectors), with accompanying loudspeakers and screens, for use in screening prints of 16mm films in small halls, rooms, and so forth.
1.3.2 Cinecameras using 8mm film have been manufactured, and are still used by amateur filmmakers; they are, of course, much lighter and smaller than 16mm cameras. In some cases, an 8mm cinecamera and a sound recorder are built into one machine, so that one person can record both image and sound at the same time. Trained filmmakers using 16mm cinecameras and good portable sound recorders can produce documentary films of high standard. Untrained amateurs using 8mm cinecameras with built-in sound recording are unlikely to produce recordings of lasting value. There are all sorts of possibilities between these extremes.
1.3.3 The video cassette recorder (VCR) was originally designed mainly to record copies of films broadcast over television (or anything else broadcast over television), and to play back the recording made on the video cassette through a television receiver. The recording, both image and sound, is made on magnetic tape. Now, feature films are mostly shown first in cinemas, and later made available in video cassette form. This means that older films become readily available for playing back through a television set in people's homes or in such places as hotel rooms. Following the introduction of the video cassette for copying purposes, video cassette recorders were developed to make original recordings images and sound on magnetic tape. These are often called camcorders: the word is formed from camera and sound recorder.
1.3.4 Cinecameras using 35mm film, and their associated sound recording equipment, will not be discussed. They are strictly for use by professional filmmakers with large amounts of money to spend. Cinecameras using 16mm and 8mm film will be discussed, along with camcorders.
2. Project Planning
2.1 A number of things need to be considered when choosing recording equipment for a project. Among the first matters that need to be considered are:
- the amount of money available for the project;
- the nature of the material to be recorded; and
- the purpose for which the recording is to be made.
3. Sound Only (Audio) Recording
3.1 The open-reel recorder
3.1.1 Open-reel recorders were the first magnetic tape sound recorders to be invented, and over a period of 50 years engineers have spent much effort on improving them. They are available in many different forms, suitable for many different purposes and circumstances. There are portable open-reel recorders capable of producing sound recording of very high quality. These are expensive. Moreover, they will produce sound recording of high quality only if they are used with microphones which are also of high quality; and these also are expensive. When new equipment is to be bought, and high quality sound recording is important, the DAT recorder is to be preferred to the portable open-reel recorder.
3.1.2 Because open-reel tape has been in use for many years, much is known about how long a tape is likely to last before it comes to the end of its useful life. Some forms of open-reel tape have been found to be reliable for long-time preservation by sound archives. Even under the best possible conditions of storage, these are not expected to have a life of more than about 50 years. More will be said about the problems of long-term storage of audio and audiovisual recordings later.
3.2 The compact cassette recorder
3.2.1 The compact cassette recorder is the magnetic sound recorder which is in common use today. This recorder is available in a great many forms. The most common forms are probably small, light machines that combine ability to record and play cassette tapes with ability to receive radio broadcasts. They are more often used to play pre-recorded cassettes bought in music shops than they are to make original sound recordings. Compact cassette recorders are the cheapest sound recorders available; most are designed to operate on mains electricity or small, cheap batteries which are usually available even in villages remote from cities and towns. Blank tapes are also cheap. Even very small, cheap compact cassette recorders, with built-in microphones, can produce recordings of the spoken word which can be heard clearly when played back. Not even the most expensive compact cassette recorder, supplied with expensive external microphones, can produce recordings as good as the best portable open-reel recorders or DAT recorders. They can produce recordings of sufficiently high quality for radio broadcasting purposes, though for this purpose they are much less suitable for recording music than recording speech.
3.2.2 Compact cassette recorders are very easy and convenient to use. Their small size, ease of use, and low cost are all advantages. Their familiarity through everyday use is also an important advantage when recording people who are not used to being recorded; such people are much less likely to feel uncomfortable or 'mike-shy' in front of a compact cassette recorder than in front of a bigger, unfamiliar and more obtrusive open-reel recorder.
3.2.3 The plastic used for compact cassette tape is much thinner than the plastic used for open-reel tape. This means that it warps and stretches easily, and this leads to increased sound distortion when the tape is played back. The useful life of compact cassette tape is much shorter than the useful life of open-reel tape. Useful life varies and is also unpredictable. Even under good storage conditions, a compact cassette tape may deteriorate so much that it is useless after four or five years, or it may last for fifteen years or even longer.
3.2.4 Compact cassette tape is therefore not suitable for long-term sound preservation. More will be said about this later.
3.2.5 Compact cassette tape recordings can be used very successfully for three purposes:
- when the recorder is used as a kind of notebook;
- when the recording is used as an aid towards the production of a written record for long-term preservation;
- when the recording is used for the immediate or short-term dissemination of material.
3.2.5.1 It is often convenient to use a small, cheap recorder to make notes for much the same purpose as notes may be written down in a book. It is much easier to make a sound recording of what someone has to say than to try to write down the exact words on the spot. The recording can be listened to later at leisure, if necessary many times, and words summarised in written notes, or transcribed exactly as they were spoken. This technique of note taking (usually combined with the making of some written notes at the same time) is used by many journalists. After the recording has been used for the production of a newspaper article, scholarly paper, book, or whatever, the tape can be treated just as a written notebook would be treated: stored (for as long as it lasts), thrown away, or the sound can be erased and the tape used again.
3.2.5.2 In other cases, the purpose may be to preserve spoken words someone's life story or account of events that he or she witnessed, or a traditional story about past events just as they were spoken. Ideally, such things might best be recorded, and the recording preserved, in audiovisual form. In practice, however, money for such an expensive form of recording and long-term preservation will seldom be available. Money even for recording and long-term preservation of audio tape will not often be available either (the considerable cost of long-term storage of tapes will be discussed later). So, in many cases, perhaps most cases, the best that can be done if such stories are to be preserved for future generations at all will be to make a sound recording which is not intended for long-term preservation, and then to transcribe the spoken words into written form. Even this is a fairly lengthy process, involving more time and skill (training and practice) than most people realise before they first attempt it. A compact cassette recording will be adequate for the purpose, but it also means that other equipment will have to be used:
- at a minimum, pen or pencil and paper (and carbon paper to make multiple copies);
- better still, a typewriter (and carbon paper), as few people produce writing that is easy for others to read;
- best of all, a word processor (computer) and its printer; the words can be stored on a computer disc, and copies printed out as needed;
- once the words are on paper in written, typewritten or printed form, they can of course be copied using a photocopier;
- photographs, even though made with a small, cheap camera, can form a useful addition to written transcriptions of this kind.
3.2.5.3 It may be that the purpose of making a recording is to have it widely heard though perhaps only within a small local community right away and for a limited time in the future. In Australia, for example, some Aboriginal communities are using compact cassette recorders to make recordings of songs and stories which are known only, or mainly, to older people. Copies of the cassettes are then made and passed around among younger people. In this way, the compact cassette recorder is being used to spread knowledge of these songs and stories among younger members of the community, and thus help to preserve the songs and stories as living traditions. Compact cassettes can easily be copied. Many compact cassette recorder-players have two cassette decks, which means that copies of cassettes can be made even in a village if this kind of machine is available. There will be a loss of sound quality when the tape is copied in this way, but this need not be a serious matter, especially if all copies are made from the original recording. (There will be loss of sound quality when the first copy is made from the original; there will be further loss if a second copy is made from the first copy rather than the original, and so on.) In some South Pacific towns there are professional recording studios which record local musicians, and sell copies of the recordings as compact cassettes. These studios sometimes have machines which can turn out many copies of a compact cassette recording fairly cheaply. In this case, there will still be some loss of sound quality, but less than if the copying is done on a machine intended for home use.
3.2.6 It has been pointed out that some of the better compact cassette recorders, used with adequate microphones, can produce recordings of speech and even music which are good enough for radio broadcasting. In many cases, radio could also be used for disseminating recordings of music, songs, stories and so on, primarily of interest to small, local communities.
3.3 Digital audio tape
3.3.1 Recording on digital audio tape is quite new, but sales of DAT recorders have been good, and prices of machines have been coming down quickly. DAT recorders are more expensive than compact cassette recorders, but the prices of the cheaper DAT recorders are in the same range as the best compact cassette recorders. Portable DAT recorders are small, lightweight, and convenient to use, though they are not quite as small, light or convenient to use as the cheaper compact cassette recorders. When a good DAT recorder is used with good microphones, the sound recording quality can be as good as that of the best portable open-reel recorders, or even better. As with all sound recorders, good microphones add considerably to the cost of the equipment. The DAT recorder is to be preferred to the compact cassette recorder when sound recording of high quality is desired. DAT recorders and tapes are more easily damaged than compact cassette recorders, so more care must be taken with them (to protect recorders from knocks and so on, and both recorders and tapes from unfavourable atmospheric conditions, such as dust). The DAT recorder will replace the portable open-reel recorder. It is already replacing open-reel recorders in many professional sound recording studios (but there are other alternatives now available for studio use).
3.3.2 DAT recorders have already proved reliable in use, and of course they are constantly being improved. It is not yet known what the useful life of a digital audio tape will be, so it cannot be recommended for long-term preservation.
3.3.3 There is, of course, no point in making sound recordings of high quality in any form unless there is good reason for the added expense involved. In particular, there is no point in making recordings of high quality with a view to long-term preservation if the expensive facilities needed for long-term storage of tapes are not available. More will be said about sound archives and long-term preservation later.
4. Audiovisual Recording
Sound recording, supplemented by photography, will be adequate or, given cost restraints, will have to be adequate for most purposes in recording the spoken word and music. Photography alone will be adequate for recording some kinds of visual images: a costume, painting, carving. When it is important to record a sequence of movement mime, say, or the making of a carving and the cost of cinecamera or camcorder can be met, then cinecamera or camcorder should obviously be used. When (and this is most of the time) it is important to record a sequence of movement, and the sound accompanying the movement dance, say, or drama, or a demonstration of the method of playing a musical instrument and the additional cost of sound recording can be met, then cinecamera with sound recorder, or the camcorder, should be used.
4.1 16mm cinematography
4.1.1 16mm cinecameras are expensive; the processing of the cinefilm has to be done in professional, commercial laboratories, and that is expensive also. There would be no point in recording sound to accompany the visual images on anything except a good portable open-reel recorder, or DAT recorder, with good microphones; therefore, the sound recording would also be relatively expensive.
4.1.2 It is to be hoped that it will be considered both desirable and financially feasible to fund the audiovisual recording of some events for long-term preservation, for scholarly, scientific, or heritage reasons. The least expensive but not an inexpensive way of making such recordings would be on 16mm cinefilm and on either open-reel or DAT sound tape. Such recordings would require the work of a team of at least two people not necessarily professional filmmakers, but again at the very least semi-professional. Modern cinefilm is fairly stable, but there would be little point in making cinefilm at considerable expense if facilities for long-term storage were not available. Problems of long-term storage will be dealt with later.
4.1.3 The production of documentary films intended for screening in cinemas, or for general television broadcasting, should be left to professional filmmakers. It is possible, however, that production of semi-professional documentary film (working from material recorded primarily for the purpose of long-term preservation) could be financially justified for local television broadcasting, or for local dissemination on video cassette.
4.2 8mm cinematography
4.2.1 8mm cinecameras have considerable limitations, and have been used mostly for the production of home movies. For this purpose, they have recently been replaced largely by the use of camcorders. Film and 8mm cinecameras are relatively cheap, and the film probably has a longer useful life than video film. 8mm cinecameras with built-in sound recording facilities may still be of limited use in producing audiovisual recordings for long-term preservation and for the use of research workers.
4.2.2 8mm cinematography is not a useful alternative to 16mm cinematography for the production of documentary films for cinema or television screening. Nor is it a useful alternative to video cassette for widespread local dissemination of audiovisual recordings.
4.3 Camcorders and video cassette recorders
4.3.1 It has been explained earlier that camcorders and VCRs use magnetic tape to record both visual images and sound. VCRs were first developed to copy material broadcast by television, and to play it back through television sets. VCRs are now widely used in this way. They are also now widely used to play back video cassette copies of older feature films.
4.3.2 The camcorder is a later development in which a video cassette on which nothing has been recorded when it is bought is used to make a recording of both visual images and sound. It has largely replaced the 8mm cinecamera with built-in sound recorder for making home movies.
4.3.3 Camcorders and blank video cassettes are both fairly cheap. A camcorder is when compared with a 16mm cinecamera small, light and easy to use. A considerable degree of skill (training and practice) is necessary to use it well. Most home video makers use it badly. Some professionals use it well (for example, in producing material for television broadcasting).
4.3.4 Video cassettes can be copied as easily as compact cassette audio tapes. Copying using commercial, professional equipment, properly maintained and operated by well-trained technicians, can be done without great loss of either sound or visual quality. Very often there is a considerable loss of quality. Copying can be done on some VCRs made for home use. There is loss of quality, but, as with compact cassette sound recordings, this may not be of practical importance for local, short-term dissemination of material, especially if copies are all made from the original recording. At the moment, the video cassette is the only means for such dissemination that is of practical importance.
4.3.5 It is important to note, however, that there are a number of different forms of recording used for video cassettes; it is usual to speak of a difference in 'format'. A video cassette recorded on a camcorder or VCR using one format cannot be played back on a VCR built to play back tapes recorded in another format. This, obviously, can create complications in the use of video cassettes, and add greatly to the cost.
4.3.6 It is not yet clear whether the video cassette is suitable for long-term preservation of audiovisual recordings.
5. Long-Term Preservation
5.1 No form of recording information will last forever. Some forms are more permanent than others. All the forms of audio and audiovisual recording discussed above were developed first of all for use in the entertainment industry; the engineers who developed them were not asked to design methods of producing recordings that would last for a long time. At present, the only well-tested form of audio recording suitable for long-term preservation is open-reel tape; the only well-tested form of audiovisual recording suitable for long-term preservation is cinematographic film. In both cases, 'long-term' means something like 50 years (though cinefilm, kept under optimum conditions, may perhaps last longer). After that period of time, the recording must be copied. Compare this with written and printed records: many libraries contain printed books that have lasted for hundreds of years; some libraries contain written documents that have lasted for thousands of years.
5.2. The problems of preserving records made by magnetic or optical recording methods have become urgent. Better methods of preserving audio and audiovisual recordings may well be developed in the near future as a spin-off from work done on the preservation of computer records. Some time in the future, technologies will be invented that make it possible to store enormous amounts of audio and audiovisual recording in a form that is relatively cheap and takes up little space; it will be a form that makes it possible to retrieve and examine any recording quickly, and to send a copy of the recording to another part of the world in a matter of minutes or seconds. However, the following matters need to be considered:
- it may be five years, or ten years, or twenty years, before this new technology becomes available;
- when it becomes available, it will almost certainly be expensive for the first few years;
- there will be an enormous job to be done in copying existing recordings into the new form.
5.3 At present, 'best practice' in sound archives and audiovisual archives is very expensive. It involves copying the original recordings onto either open-reel audio tape or cinematographic film. This has to be done by well-trained technicians (whose labour is expensive), using machines that are expensive to buy and expensive to maintain in good working condition. The tape or film has to be stored under carefully controlled conditions of temperature and humidity. The storage facilities are expensive to build. It is not easy to maintain constant levels of temperature and humidity, so the storage areas require a lot of electrical energy, and the supply of electricity has to be constant; there must be continual checking of the temperature and humidity, and continuing careful maintenance of the air conditioning equipment. The amount of audio and audiovisual recording being done today is vast. It is obvious that even in wealthy countries only a very small amount of the material recorded is likely to be selected for long-term preservation under best practice conditions.
5.4 Even in the larger and wealthier South Pacific countries, there are very few sound archives, or film and sound archives, that meet best practice standards. It is unlikely that any of the smaller South Pacific countries will, in the foreseeable future, have sound, or film and sound archives, that can afford standards even approaching best practice in such institutions as the Australian National Film and Sound Archive, or the National Library of Australia.
5.5 For the most part, there is little point in making recordings on equipment which is of high quality, and therefore costly, unless arrangements can be made for long-term preservation of the recordings. This should be taken into consideration when arrangements are made for funding any recording project. In general, if long-term preservation of material to be recorded is thought to be of high importance, then some arrangement should be made for this preservation in an institution in one of the larger South Pacific countries, or elsewhere.
5.6 It has been suggested already that the best practical method for long-term preservation of much material (spoken word) involves making a sound recording using a cheap compact cassette recording, and transcribing the words into written or printed form. This is not ideal, but it is adequate for many purposes, particularly if the transcriptions are supplemented by photographs.
5.7 Periodic copying of open-reel and compact cassette sound recordings, and video cassette recordings, should be considered as a possibility for medium-term storage. Some loss of quality will occur each time a copy is made, but this can be minimised under certain conditions, such that:
- the recordings are kept under conditions that meet at least minimal requirements, e.g. an airconditioned storage area;
- the recordings to be copied are checked regularly to ensure that copying can be done before deterioration of the recording has gone too far; and
- the copying is done by properly trained technicians, using good equipment which is well maintained.
5.8 All this would be expensive (the capital and maintenance costs of equipment for copying video cassettes in particular), but a great deal less expensive than meeting best practice standards.
5.9 In theory, digital audio tape can be copied without any loss of sound quality (there is always some loss of quality when an open-reel or compact cassette recording is copied). Some sound archivists are experimenting with preservation of digital audio tapes by periodic copying. It has yet to be shown that this method can be relied upon in practice. Its adoption would require all the conditions mentioned above with regard to compact cassette tape, but also:
- even greater vigilance in regular checking of tape; and
- the use of equipment that would be more costly to buy, and probably a great deal more expensive to maintain in good working condition.
6. Summary
6.1 The technology of audio and audiovisual recording and reproduction is changing rapidly. Techniques suitable for use by professional filmmakers or sound recording companies have not been discussed, nor have certain other techniques, recently introduced and as yet not well tested or widely used.
6.2 All of the forms of recording considered have advantages and disadvantages, and these should be considered in relation to the kind of material to be recorded, the purpose for which the recording is being made, and relative costliness.
- The open-reel portable recorder can produce sound recording of high quality, and open-reel tape can be expected to have a longer useful life than either compact cassette or digital audio tapes; it is a relatively expensive form of sound recording.
- The compact cassette recorder is cheap, easy to use, and likely to be familiar and thus not alarming to most people likely to be recorded, but even the best compact cassette recorders cannot produce recordings of such high quality as the best open-reel or DAT recorders, and the useful life of a compact cassette recording is limited.
- The DAT recorder is relatively cheap and easy to use. It is perhaps more likely to alarm people unfamiliar with sound recording situations than the compact cassette recorder, but less so than the portable open-reel recorder; the useful life of DAT recording is probably limited, especially if kept under less than ideal conditions. The DAT recorder is to be preferred for recording in the field where high quality sound recording is needed. DAT recorders need to be handled with more care than open-reel or compact cassette recorders, and the tapes will deteriorate more rapidly than open-reel or compact cassette tapes if kept under unfavourable conditions.
- The greater expense of open-reel or DAT recording cannot be justified unless there is need for high recording quality. In most cases, it is not justified unless arrangements can be made for long-term preservation of the recording.
- The cheaper compact cassette recorders are adequate for recordings which are intended for long-term preservation in written transcription, and for short-term dissemination of recordings in compact cassette copies; costlier compact cassette recorders are suitable for producing recordings to be broadcast by radio.
- 16mm cinematography can be used in the production of film of high quality, but high quality is only likely to be produced by well-trained professional or semi-professional teams. Its cost is not likely to be justified unless the finished film is intended for screening in cinemas or such places as village halls, or unless the original recording is intended for long-term preservation (and this can be arranged in advance of filming).
- 8mm cinematography is cheaper than 16mm cinematography. Finished film of high quality cannot be expected, but it is relatively easy for amateurs to use. It may have limited use for documenting, for research purposes, such things as dance or drama.
- The video recorder, or camcorder, using cassette tape is a much cheaper form of audiovisual recording than cinematography. It is suitable for the relatively cheap production of audiovisual recordings to be broadcast by television, or played back on VCRs connected to television sets in (for example) homes, hotels or schools. It is the only form of audiovisual recording that needs to be considered for recordings intended for short-term local or regional dissemination. It has not yet tested well for use in long-term preservation. Even short-term preservation by repeated copying is likely to be costly (and differences in format could add greatly to costs). It is also likely, in practice, to result in considerable loss of quality in both image and sound.
