Apple Final Cut Pro 7 - Manual (Page 1614)

Reel Conflicts
If you create a transition between two clips from the same reel in your sequence,
Final Cut Pro considers this to be a reel conflict, because the resulting EDL event would
be impossible to perform in a tape-based editing system. This is because in a linear editing
suite, a transition requires two video sources, but you can’t put the same tape in two
decks at the same time.
Reel conflicts can be addressed in several ways, depending on the abilities of the
tape-to-tape editing suite you are using:
B-Reel Edits
In a linear editing suite, transition events that require two different shots on the same
reel can be performed by first copying the second shot of each transition to a new tape,
called a B-reel. Final Cut Pro can automatically create a B-reel EDL, which you can use to
assemble a tape with any necessary shots. The B-reel tape is automatically assigned its
own reel name, and shots in the EDL for your main sequence are replaced with
corresponding shots on the B-reel.
TITLE: MASTER SEQUENCE BREEL1
001002AA/VC02:18:32:07 02:18:56:19 01:00:00:00 01:00:24:12
TITLE: MASTER SEQUENCE
001002VC02:10:42:13 02:11:16:18 01:00:00:00 01:00:34:05
001BREEL1VD024 02:18:32:07 02:18:56:19 01:00:34:05 01:00:58:17
* FROM CLIP NAME:DEBRA ENTERS CAFE WS
* TO CLIP NAME:DEBRA SIDEWALKING
1614 Chapter 96 Importing and Exporting EDLs