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The editing of recordings began as soon as humans began video taping stuff. It is the removing of unwanted material (e.g., commercials, certain scenes, etc.) during or after recording. It is also done when recording from one videocassette recorder to another. Starting with the first Betamax you edited during recording by simply pressing the pause button. The tape stopped moving (the video head disk continued to spin) and when pause was released the recording was resumed. The junction point between the two scenes was obvious and choppy. Bad enough to earn the nick name "crash edits" in tech-speak. When Sony incorporated the Micro-Timing Phase circuitry (identified as µTP) into their Betamax VCRs these editing junction points became greatly improved. This advanced technology incorporates smart circuitry that controls the start of the recording and the capstan rotation to synchronize the junction of the edit points. This is possible because every picture (frame) starts with a sync pulse. It tells the monitor (and VCR) when to begin each individual frame that passes before your eyes at thirty frames per second (fps). This produces the effect of a moving image. When you pause a tape you are looking at a one of those single frames. Here is the way µTP operates when pause is requested during recording, and why it is such an improvement over crash edits. When the tape is paused during recording it is reversed for a few frames before it goes into the record standby mode (pause). Everything is now ready to swing into action when pause is pressed again to resume the recording. When pause is released the capstan begins rotating and as the tape moves forward the µTP circuit looks for and finds the next sync signal on the tape. It then starts the recording when it is synchronized with the sync signal coming in. Actual video recording commences once that marriage has been made. This changeover exchange results in a much smoother transition point between the two frames. The picture no longer loses sync, jumps or tears because the edit points are now synchronized. The µTP circuit will work even if the machine has been stopped. To renew the connection the VCR is simply placed into the record pause mode at the point where you want the next scene to begin. The tape backs up and when pause is pressed the recording commences at the sync points. The system isn't perfect. One unavoidable fact is that the capstan has to start rotating from a dead stop. Sometimes a microsecond of lag time can creep its way into the video. This is why the machine has to be in perfect running condition so it can accurately control the tape movement. No slipping is allowed from graphite buildup on the capstan, guides or pinch roller. One other thing, you can fool the circuitry by changing tape speeds between the edit points. That's a no-no. Good as it is µTP is surpassed by an even better method. Near-perfect professional transitions are possible using what is called pre-roll editing. This highly advanced method is only available between the
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