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Using the A/B mode to fine-tune a transition: Lesson 6-3
Because the developers of Premiere Pro created version one of Premiere Pro from the ground up, they had the opportunity to make some fundamental decisions. One was to no longer include A/B editing in the Timeline.A/B editing is old-school, linear, film-style editing. Film editors frequently use two reels of film: an A-roll and a B-roll, which are usually duplicates made from the same original. The two-reel approach permits cross-dissolves from the A track to the B track.The advantage of A/B editing in older versions of Premiere was that it let you more easily modify transition positioning and start and end points than you could on single tracks NLEs.Here's the good news for both A/B and single-track editing camps: Premiere Pro includes all of that functionality in its Effect Controls panel.
Working with the Effect Controls panel's A/B feature
The Effect Controls A/B editing mode splits a single video track into two sub-tracks. What would normally be two consecutive and contiguous clips on a single track now display as individual clips on separate sub-tracks, giving you the option to apply a transition between them, to manipulate their head and tail framesor handlesand change other transition elements.
NoteYou might need to expand the width of the Effect Controls panel to make the Show/Hide Timeline button active.
| 5. | Drag the border (cursor highlighted in the next figure) between the A/B timeline and the transition parameters section to expand the view of the timeline. |
| 6. | Hover the cursor over the white edit line at the center of the transition rectangle (highlighted in the next figure).That's the edit point between the two clips, and the cursor that appears there is the Rolling Edit cursor ( )the same Rolling Edit you encountered in the Trim panel. |
| 7. | Drag the Rolling Edit cursor left and right and note how the changing out-point of the left clip and the changing in-point of the right clip show up in the Program Monitor. |
NoteAs was the case when you used the Rolling Edit tool in the Trim panel, moving it left or right does not change the overall length of the sequence. [View full size image]
| 8. | Move the cursor slightly left or right and note that it changes to a Slide tool ( ). |
| 9. | Use the Slide tool to drag the transition rectangle left and right. |
NoteThat changes the start and end points of the transition without changing its overall length (default duration: 1 second). The new start and end points show up in the Program Monitor. But unlike the Rolling Edit, moving the transition rectangle does not change the edit point between the two clips.
| 10. | Click the drop-down Alignment list and click through the three available options: Center at Cut, Start at Cut and End at Cut. |
NoteThe transition rectangle moves to a new location as you make each change. These three locations mimic the options when you drag a transition to the Timeline. Additionally, if you manually change the transition location, the Custom Start alignment option becomes active.
| 11. | Drag an end (it doesn't matter which end) of the Viewing Area Bar to the edge of the A/B timeline.As shown in the next figure, that expands your view of the two adjacent clips so you can see the beginning of the left clip and the end of the right clip. |
| 12. | Drag the right and left edge of the transition to lengthen it. |
Two other ways to change transition duration
 | As a reminder, you can also change the duration value by typing in a new time or by clicking on the duration time and dragging left or right to decrease or increase its value. |
Dealing with inadequate (or no) head or tail handles
Eventually you will want to place transitions at edit points where you don't have adequate head or tail handles. This might be because you paused the camcorder too soon or didn't get it started fast enough. You might want to add a transition to ease what would be an abrupt cut edit. Premiere Pro deals with that elegantly.Lesson 6-1 Start sequence.
| 1. | Click the Lesson 6-1 Start tab, marquee select the two clips in that sequence and press Delete. |
| 2. | Drag Video 6i and Video 6j to the Timeline.This time you will not trim the clips to give them head and tail handle frames. Those little triangles that show there are no extra frames available will be in the upper corners at the edit point. |
| 3. | Drag the Wipe transition to that edit point.You will get the "Insufficient Media" alert again. Click OK. |
| 4. | Click the transition to display it in the Effect Controls panel and note that the transition rectangle has parallel diagonal lines running through it, indicating the lack of head or tail frames. |
| 5. | Set the transition direction to go from South to North.This direction will give you the clearest picture of how Premiere Pro deals with a lack of head or tail frames. |
| 6. | Lengthen the transition to about 3 seconds by dragging the right and left edge of the transition rectangle. |
NoteThe A and B clips retain their light blue color, indicating there are no head or tail frames available for overlap.
| 7. | Drag the CTI slowly through the entire transition and watch how it works: |
- For the first half of the transition (up to the edit point) the B clip is a freeze frame while the A clip continues to play.
- At the edit point, the A clip becomes a freeze frame and the B clip starts to play.
- When played at regular speed (at the default 1 second duration), few viewers would notice the freeze frames.
When only one clip has no head or tail handles
In this lesson's example both the A and B clips have no head or tail handle frames. Frequently only one clip will have no head or tail room. In those cases Premiere Pro would have forced placement of the transition to start or end at the edit point depending on which clip was lacking extra frames for the overlap.You can override that by dragging the transition into the clip lacking extra frames. The next figure shows examples of both circumstances with the transition centered. The diagonal lines indicate
