Computers help coordinate the editing process.

Editing by Computer

The real beauty of SMPTE time code editing is that special edit controller computers can do most of the work for you. The most sophisticated of these machines can control several tape machines and a programmable switcher at the same time. With more than one playback machine (provided they're properly time base corrected), you can dissolve, wipe, key, and do other effects between machines. All of this can be entered into the edit controller, and it will do everything: cue and preroll the machines, command the switcher to do special effects between the machines, and have the record machine do the actual edits. All you have to do is program the computer properly by entering the editing script containing all the scenes in sequence designated by SMPTE time code.

Drop Frame/Non-Drop Frame Editing

Throughout this book, in order to keep things simple and understandable, a frame rate of 30 frames and 60 fields per second has been used. That is not exactly accurate, however. In order to add the color information to the luminance information, a slightly different frame rate is required. In reality, the NTSC system has 59.94 fields and 29.97 frames per second. For our needs up to now, this has not been a problem. But when dealing with SMPTE time code it does create a problem. Since SMPTE time code uses 30 frames per second when there are only 29.97 frames per second, the timing will be off before you get very far into the tape. By the end of the program, SMPTE time code will show your program to be a different length than it really is. To compensate for this problem, time code generators and editors will allow either a drop frame mode or a non-drop frame mode to be selected. In the drop frame mode, at selected places the system will drop a frame so that a second of time will only have 29 frames instead of 30 frames. This will keep the time code of a program and the actual time of the program the same. In the non-drop frame mode the time code and the actual length of the program will be different. You will need to decide which mode works best for your particular situation.

These computer-controlled systems can do remarkable things, but you have to keep one thing in mind. The computer can carry out your commands accurately, but it takes the creativity and organization of a person to create, develop, and refine the show's idea and execution.