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Return to Field Production
Modern DV cameras and DAT audio recorders use precise controllers to maintain a steady recording speed. The controllers are accurate enough that both machines will keep the exact same pace for ten to fifteen minutes. Because of this, it is easy to record picture and sound separately and then to match or sync them later during editing. The hard part is knowing the exact point when they started. Movies have traditionally marked the sync point with a slate or clap board. The camera and tape machine are both started, someone holds the slate in front of the camera's lens and closes the arms together. When the slate's arms are snapped together the camera records the frame when the arms touch and the tape machine records the "clap" sound. If you match the clap sound with the frame then the audio and picture are in sync. Sometimes one needs to slide the audio track a frame or two one way or the other. 
The next problem is locating the audio clip you want when all you have to go on is a succession of "claps" on the tape. One way to provide a reference is to write the time code from the DAT recorder on the slate. The camera records the time code and this provides a permanent reference to where the matching audio clip is on the DAT tape. This makes editing a straightforward process.
To insure having continuous time code on the DAT tape, follow these steps.
- When you insert a new DAT tape be sure to initialize the tape according the DAT recorder's manual, then
- For every take:
- At "cut" let the tape run for 5 seconds then stop.
- Rewind the tape 2 seconds.
- Write the time code at this point on the slate
If you begin recording where you stopped at "cut" the DAT recorder resets the time code to 00:00:00. If you back into previously recorded material, the machine sees the existing time code and continues where it left off.
As an aside: It is also useful to have continuous time code on your DV tape. You can use the same "back up 2 seconds" ploy. You can also pre-record the tape with color bars (This is easy to do with any camera that has an internal color bar generator). This will put time code across the whole tape and when you re-record the time code is left alone. DAT tapes cannot be pre-recorded in this fashion.
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