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The editing of recordings began as soon as video taping began. It is done to the remove unwanted material (e.g., commercials, certain scenes, etc.) during or after a recording has been made. It is also done when recording from one videocassette recorder to another (called dubbing). Starting with the first Betamax you edited out unwanted stuff 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 sloppy. Bad enough to earn the nick name "crash edits" in tech-speak. After Sony included µTP (Micro-Timing Phase) into their Betamax VCRs these editing junction points became greatly improved. This advanced technology incorporates smart circuitry that controls the start of an edit by controlling the capstan rotation. It does this to synchronize the junction points. This is possible because every picture (frame) starts with a sync pulse. It tells the monitor (and VCR) when to begin each individual picture that passes before your eyes at thirty frames per second (fps). Which produces the effect of a moving image. When you pause a tape you are looking at a one of those single frames. µTP operates to join together the end of one frame to the beginning of another. It starts to happen when pause is activated during recording. And here is why this is such an improvement over crash edits. When the tape is paused during recording µTP swings into action and runs the tape backwards a few frames before it goes into the record standby mode (in pause). When pause is pressed again to resume the recording the capstan begins rotating and as the tape moves forward the circuit looks for and finds the previous sync signal on the tape then starts the recording when it is synchronized with the signal coming in. Actual video recording only commences once that marriage has been made. This changeover or union 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 synced together. The µTP circuit will work even if the machine has been stopped between edits. 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 the 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 doesn't involve stopping the capstan at all. Intended for editing between machines it is only available between the
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