The ability to record and play back video signals is crucial to nearly any video production. The majority of programming on network television is broadcast from a recording, and most of what isn't relies at least in part on roll-ins, or recorded segments (see Chapter 12). Thus, we need ways of recording and playing back high-quality video signals (along with their associated audio signals). Intertwined with the recording and playing back of video signals are the basic control functions of channeling, moving the signal to and from the recording device (and other equipment), and monitoring, making sure the recorded signal is as true to the original as possible.

Video signals, whether in analog or digital form, have several unique characteristics that can make these functions a bit more complicated than you might expect. Certainly, compared with audio signals (see Chapter 7), channeling, monitoring, and recording and playing back video signals require much more complex technical equipment. Consider the fact that the technology to record audio existed for several decades before the advent of the first video recorder. Indeed, when Ampex introduced the first commercial videotape recorder (VTR) in 1956, it sparked a revolution in television production.

Now digitization, along with the digital channeling and storage of video signals, is creating another revolution, which holds the possibility of bringing even greater changes than those brought by tape. As video exists increasingly in digital form, it can seamlessly interface with computers, and—even more important—computers and computer equipment can be used to perform basic control functions. You have already seen how digital technology is changing other video production components such as cameras, switchers, and DVE units. In the same way, digitization is changing how video signals are recorded and played back, as tape machines are being replaced by video servers, powerful computers with large storage capacity. The chief advantage of such servers is that they are nonlinear, meaning you can access anything stored on them nearly instantly, without having to fastforward or rewind as you do with tape. When we combine video servers with computer network interconnections, we allow any number of people in a production facility to simultaneously access and manipulate the video information.

But the day when every station and production facility has gone all digital and "tapeless" is still a ways off. For that reason, a significant portion of this chapter concentrates on the function and operation of VTRs, which are likely to be prevalent for at least the near future. However, this chapter begins with a discussion of some technical aspects of video (in analog and digital form) and their impact on how video is stored and distributed.

There are both important disciplines and techniques to the operation of video storage and distribution equipment. The disciplines include an understanding of how video is recorded, digitized, and distributed, while techniques include specific operating and maintenance procedures. This chapter includes the following topics:

• The basic components and special attributes of video signals (10.1)
• The advantages of digital signals over analog signals, and the basic methods of converting analog information into digital video (10.2)
• The importance of compression in digital video, and the major methods of compression (10.2)
• The basic design and operation of digital video servers, including the concepts of ingesting and asset management (10.3)
• Other digital-based storage options for video, including optical media and memory cards (10.3)
• Principles of videotape recording, and the function of various videotape tracks (10.4)
• The basic layout and operation of typical videotape recorder operational controls (10.5)
• Basic procedures for operating and maintaining videotape equipment (10.6)