Apple M8728Z/A User Manual - Page 37

Synchronization Basics Synchronizing the audio with the video image can be fairly easy as long as some care was taken during the shoot. There are two aspects to synchronizing your audio: establishing sync at a particular point in each clip, and playing the audio at the correct speed so that it stays in sync. While shooting, you must provide visible and audible cues to sync on. The most common method is to use a clapper board (also called a slate or sticks) at the beginning of each take. Even better, you can use a timecode slate that displays the sound recorder's timecode. To sync the audio with the video, position the video at the first frame where the slate is closed, then locate the sound (or timecode) of the related audio. Note that production requirements occasionally require the slate to occur at the end of the take, generally with the slate held upside down. Because the film is often either slightly sped up or slowed down during the telecine transfer, the audio must also have its speed changed. If the audio is being synced during the transfer, the speed change is handled there. If the audio is being synced to the videotape after the transfer, the speed change must happen then. Synchronizing During the Telecine Transfer During the shoot, you typically start the sound recorder a little before the camera rolls and stop it a little after the camera stops. Because you end up recording more audio than film, you cannot play the audio tape and the film through several takes and have them stay in sync. If you want the telecine transfer to record synchronized audio on the videotape, you must either use the scene-and-take transfer method, synchronizing each take on its own, or create a synced sound roll before performing a camera-roll transfer. A large benefit to synchronizing during the telecine transfer, aside from having videotapes with synchronized audio ready to be captured, is that the telecine log usually includes the audio timecode and sound roll number information. Importing the log into Cinema Tools makes it possible to export an audio EDL so that an audio post-production facility can recapture the audio clips at a higher quality later, if needed. • NTSC transfers: When transferring film to NTSC video, it is always necessary to run the film 0.1 percent slower than 24 fps (23.976 fps, typically referred to as 23.98 fps) to compensate for NTSC video's actual frame rate of 29.97 fps (instead of an ideal 30 fps). Because the film has been slowed down, audio too must be slowed to maintain sync. • PAL transfers: PAL transfers using the 24 @ 25 method (speeding up the film to 25 fps) require that the audio also be sped up if you are syncing the audio during the telecine transfer or if you intend to edit the video at this rate. If you are transferring the film to video using the 24 & 1 method (recording an extra video field every twelfth film frame), you should run the audio at its normal speed regardless of where sync is established. Use 25 fps timecode for the audio in this case. Chapter 2 Before You Begin Your Film Project 37