"It's always best to start at the beginning" replies Glinda, the Good Witch, to Dorothy in the Wizard of Oz. This course has been designed to introduce students to the theory and essential elements of Digital Video (also known as "Desktop Video"). However, there would be no digital if there were not first analog, so...here we go! This material should be used as directed to complete any Review Questions Sheet that is assigned.

    By now, you should have completed your first year of Introduction to Digital Video and Animation. You have been introduced to the concept of video theory and video tape. Some of this material may be review, but it still contains interesting and educational information that should be of good use.

    The idea of "moving pictures" has not changed very much since the time when Thomas Edison developed his "amazing moving picture machine". Just like movie film, any video is simply the process of recording many still images and then playing them back at a speed that gives the illusion of fluid motion (called the "persistence of vision"). Specifically, video still images are recorded and then played back at a rate of 29.97 or 30 frames per second (FPS).

    Initially, television (video) cameras were stand alone devices. They were able to capture moving images. However, it was necessary for them to be hooked up to another device called a video tape recorder (VTR). That was the only way that images could be "saved". The tape could then be rewound and replayed. The video tapes were "open reel" or "reel-to-reel" recorders with tape wrapped on them, much as film is wound on a film reel.

    In the old days, much television was done as live broadcasts. This was due to an inability to be able to electronically edit the tape and sometimes tape was actually cut and "spliced" with tape much as movie film was edited. The editing process also consisted of a method called "crash" or "insert" editing. This consisted of hooking up one deck to another, and pressing "play" on one deck, and then "record" on the other when the desired section of tape was reached. Later, more sophisticated editing decks were developed that could produce transitional effects and smooth edits.

    One of the major innovations that came along was the development of a device that combined the characteristics of both a camera and a VTR. Hence, the combination of names coined the term "camcorder". These devices used smaller tape reels encased in a plastic box. These tapes came to be known as "videotape cassettes".  These protected and portable tapes and the portable "camcorders" revolutionized the television industry and essentially revolutionized the taping of news and historical events. The video deck that was used to play back, edit, and record these tape cassettes came to be known as a "video cassette recorder" (VCR).

    Tape sizes were still an issue however, since tape formats included 1" tape and smaller 3/4" tape. They still took up a lot of space and the decks were large, requiring large studio and production facilities. It wasn't until the development of 1/2" videotape cassettes that video really became the portable medium we enjoy today. Initially, there were two basic formats that struggled to take over the 1/2" portable video market. The "VHS" format, developed by the JVC Corporation and the "Beta" format, developed by the Sony Corporation. Needless to say, the "VHS" format became more widely established, eclipsing Sony's "Beta" format (which is now just a footnote in video history!) The "VHS" format is still hanging in there after all these years, but is now being challenged by newer technologies. ("VHS-C" tapes are still 1/2" tapes, but are on smaller reels and in smaller cassettes...they are not digital...neither are standard 8mm Video Cassettes).

    Whew! That's a lot of stuff to remember! All that information, and I haven't even mentioned the word "analog". (Must be a LONG section...huh?) Well now we come to the "digital" and "analog" stuff. Every thing that we discussed about video so far is now classified as "analog". That means that any video devices that still rely on older videotape technologies, are considered to be "analog video" devices.

    "Analog" video recording technology relies on the ability to record analog still images onto moving tape as it moved past the spinning "helical-scan" (slanted) recording drum, which records images like this...//////////////////////////////. There are thirty "slashes" in the previous sentence that you must imagine to be still images. That would be equal to one second of tape. As the head spins, it has two (or four) heads protruding out of the drum. As each head hits the magnetic tape, it records an image much in the way that music is recorded on tape. When it is played back, the tape moves along the spinning drum, and the heads read each slash as an image. That is as simple of an explanation as I can supply. That is the basic idea behind "analog" video technology.

    Now, you'll notice that all this time we haven't mentioned the word "computer". That is where the "digital" part begins. However, we must explain that the newer digital technologies have also impacted analog technologies, resulting in newer terminology for old processes. That will be covered when you learn about "linear" and "non-linear" editing...but that's another day!

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