Apple Cinema Tools 3 - Manual (Page 161)

Chapter 9 Export Considerations and Creating Audio EDLs 161
AIFF Files
An AIFF file contains only the audio, and cannot be easily changed. You must export a
separate file for each audio track. As with OMF files, AIFF files can contain the audio
from non-timecode sources, such as audio CDs. (Audio EDLs describe only edits using
timecode-based sources.)
See the Final Cut Pro documentation for information on exporting multiple tracks as
AIFF files.
Audio Speed
Often the play speed of the edited audio is slightly different from what it was when it
was originally recorded (its natural speed). This compensates for film speed changes
made during the telecine transfer. Anytime you are editing at 29.97 fps or 23.98 fps, the
audio is running 0.1 percent slower than its natural speed. If you are editing at 25 fps
and the telecine transfer film rate was 25 fps, then the audio is 4 percent faster.
This speed difference is maintained when you export an AIFF or OMF file. Be sure to
find out the requirements of your audio postproduction facility with regards to audio
speed issues before you export the files.
Exporting an Audio EDL
Just as the final edited video from Final Cut Pro is not generally used when conforming
the negative, the edited audio might not be used. If you intend to recapture and reedit
your audio at an audio postproduction facility, you need an audio Edit Decision List
(EDL) indicating how the audio clips are used in the edit.
While Final Cut Pro’s EDL contains both video and audio information, it may not contain
references to the timecode and reel numbers from the original production audio tapes,
depending on how the clips were captured and how the video was synced to the
audio. A Cinema Tools database makes it possible to generate an audio EDL with the
original production audio timecode and reel numbers.
Where’s the Audio Timecode?
Film productions use a double system (separate camera and audio deck) for capturing
the pictures and sound. You must sync the two of them together, either during the
telecine transfer or before capturing the clips with Final Cut Pro.
If your audio is synced during the telecine transfer and recorded onto the audio tracks
of the videotape, then the timecode and reel number of the original audio source tape
is no longer part of the clip and all edits within Final Cut Pro refer only to the video
timecode and reel number. Fortunately, the telecine log created during the transfer
usually contains the audio information, and adds it to the database when you import
the log into Cinema Tools. You can also manually enter the audio information if no
telecine log is available.
UP01101.Book Page 161 Thursday, March 10, 2005 3:16 PM