How Audio Is Handled in the Offline/Online Editing Process
The offline/online workflow tends to focus on video, but how is audio handled? Audio
has much lower data requirements than video, so audio is almost always captured at its
native sampling rate and bit depth, even for offline editing. This means the audio is
ready for a final audio mix without recapturing.
During the offline editing phase, audio clips are synchronized with video, placed in the
sequence, and basic level adjustments are made. Once editing is finished and the
picture is locked, audio is mixed in the audio mixing and sweetening phase. You can mix
your audio in Final Cut Pro, or transfer your audio files and audio edit decisions to an
audio post-production application.
Offline and Online Editing
The audio mixing phase is analogous to the video online edit session: the goal is to
produce a continuous, natural-sounding mix by setting proper levels, setting panning
(locating sounds in different speakers, either for stereo or surround sound), and using
any necessary audio filters. When the audio mix is complete, you bring it to the online
edit session for an audio layback into the finished sequence (or directly onto the
finished master tape). For more information about audio mixing in Final Cut Pro, see
Volume III, Part I, “Audio Mixing.”
To transfer your sequence audio to an audio post-production application, you need to
export two things:
Â Audio clip information: In and Out points, location in sequence, and audio levels.
Some people may simply call this an audio Edit Decision List. The audio media itself
is not included.
Â Audio media files: These are the actual media files referred to by clips in your sequence.
You can export your audio edit decisions to project interchange formats such as OMF,
AAF, or the Final Cut Pro XML Interchange Format. Some audio applications can also
Audio media files can be exported as AIFF, WAVE, Sound Designer II (SD2), or any other
QuickTime-supported audio file format.
Using the OMF and AAF formats, you can export both sequence
information and media files in a single file. Although this file can be quite large, it can
be convenient to have all the audio data you need in one self-contained file. Both an
EDL and a file in Final Cut Pro XML Interchange Format contain only sequence
information, not audio media. This means that in addition to the project interchange
file, you need to transfer your audio media to the facility doing your mix.
The interchange format you choose depends on which formats your audio application
recognizes. For more information, see Volume III, Chapter 10, “Exporting Audio for
Mixing in Other Applications.”
Media and Project Management