Magazine article American Cinematographer

Video Formats

Magazine article American Cinematographer

Video Formats

Article excerpt

The filmmaker, approaching a video production for the first time, is faced with a choice of format similar to the choice he makes about whether to work in 70mm, 35mm, 16mm, or 8mm. He may also have to decide whether to combine formats and choose the one most suited for each phase of his work. As with film, many of the choices are dictated by the market for which the production is destined, and many are dictated by economic considerations. The more he understands the capabilities and limitations of each format, the better he will be able to get the best quality for his money and the most useful end product.

Video formats can be categorized according to the characteristics of the signal into which the visual image has been translated, by the way in which this signal is recorded, or by the physical characteristics oi the medium onto which it is recorded. To some extent the size of the tape used for recording a video signal is an indication of the limitations of the quality of the image that can be recorded- in the same way that the gauge of a motion picture film is an indication of the limitations of the image which can be recorded photographically. One naturally assumes that the image quality possible with 2'' tape equipment is superior to that possible with ½'' or ¾'' equipment. However, this is not true for 2'' as opposed to 1'' videotape, and the reason is that the physical size of the tape is not, per se, the limiting factor. With film, the physical area on which the image is recorded is a directly limiting factor for any given film emulsion, (you get more resolution in 35mm than you do in 16mm), but with video tape, as in sound recording, the limitatioins are more a function of the speed with which the tape moves across the recording head -or more precisely, the "bandwidth", or range of frequencies which can be recorded. Because of the difference in the design of 2'' and 1'' videotape recording machines, it is possible to achieve the same image quality with 1'' as with 2'', and 1'' videotape is rapidly replacing 2'' as the standard format for broadcast quality recording.

Tape Sizes

There are five different sizes of tape currently used for video recording. Two inch tape recorders were the first to be developed and were the industry standard until recently. One inch recorders, originally developed for non-broadcast use, are now capable of quality comparable to that of 2'' machines and offer a variety of other advantages. Both 2'' and 1'' videotape recorders are reel-toreel machines. The smaller tape formats generally use cassettes. Threequarter-inch videotape was developed as a "consumer" product format and was not originally conceived as a medium for broadcast quality video recording. Advances in technology, however, have made it possible to achieve a quality on ¾'' cassettes which may, in many cases be considered acceptable for broadcast and which is certainly adequate for a wide range of non-broadcast professional uses. Half-inch videotape is primarily a format for home use and for home use distribution, but there are some professional applications, such as industrial production and certain off-line editing techniques. The latest tape format to be introduced is the Technicolor ¼'' cassette format. While it is essentially an amateur format at present, it may represent the possibility for future developments in more compact video formats.

In general, we can say that the use of ¼'' and ½'' tape is roughly comparable toSmm film; ¾'' tape to 16mm film; and 1'' or 2'' to 35mm film.

Recording Formats

Videotape formats are also distinguished by the way in which the signal is recorded on the tape or the way in which the tape and the record head move in relation to each other. Twoinch machines have four recording heads on a drum, rotating at 90 degrees to the direction of the tape travel, so that the track is recording across the width of the tape as it moves past the drum. This is called a quadruplex, or "quad" format, and it enables the heads to move in relation to the tape at a scanning speed (or writing speed) of 1560 inches per second, even though the tape is moving through the machine at a rate of only 15 inches per second. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.