Specifications
Chapter 4: Avid Unity MediaNetwork Workflows for Pro Tools 47
Frame-Rate Accurate Video Editing and
Sample-Rate Accurate Audio Editing
After a sequence has been exported back to In-
terplay from Pro Tools, a number of additional
media files appear in the Interplay Window and
in the bin. Some have names containing the
prefix Sample accurate edit. These are the addi-
tional media files that Pro Tools creates to make
sure that the Avid application receives frame-ac-
curate audio. Sample-accurate edit media files
are visible if you zoom in on portions of the im-
ported audio in the Timeline.
The following illustration shows Sample accu-
rate edit files in the Interplay Window.
Avid video editing applications edit with frame
accuracy. This means that when using an Avid
application to work on a 30-fps project, you can
edit at 30 different locations for every one sec-
ond of video. Pro Tools edits with sample rate
accuracy. In a 48 kHz session, there are poten-
tially 48,000 locations to edit for every second of
audio.
When Pro Tools exports a sequence, it must en-
sure that the audio media files line up on frame
boundaries. To do this, it might have to split an
existing audio region into three regions. For ex-
ample, the following illustration shows a 5-
frame video clip and a corresponding audio re-
gion. In Pro Tools, the audio regions might not
line up on video frame boundaries.
In order to export frame accurate audio regions,
Pro Tools splits the audio media on frame
boundaries and fills any gaps with silence. The
following illustration shows the resulting audio
regions that are exported to the Avid applica-
tion.
To cut down on the number of sample accurate
edit files, the Pro Tools editor can perform a
Bounce to disk for each track (or a bus-record to
an audio track) rather than exporting tracks that
contain all of the audio edits.
Sample-accurate edits in the Interplay window
Sample-accurate
edit audio files
The original audio clip does not line up on video frame
boundaries
Exported audio regions line up on video frame
boundaries
1 Pro Tools
audio region
5 frame
video clip
3 exported
audio regions
5 frame video
clip
New audio regions
padded with silence