Understanding Transitions and the Single-Track Edit
Liquid Edition uses a single-track edit system, which means all the media clips exist on a single track. However, you can have as many tracks as you want, and then you can combine them together to create some spectacular effects.On the opposite side of the fence is the A/B roll method, which some other NLE programs use. This method needs three lines to create a transition; these lines are often static and can't be customized to your individual needs.Both single-track edit and A/B roll have advantages and disadvantages, particularly when it comes to the everyday use of transitions, which you look at in the next few pages.
The A/B roll method
The A/B roll method uses the concept of two tracksTrack A at the top, and Track B at the bottomand in between them, you insert a transition. Figure 8.1 shows a graphical representation of this. The mark-in point of the clip on Track B is the start of the transition; the mark-out point of the clip on Track A is the end of the transition.
Figure 8.1. The A/B roll method with overlapping clips.

The single-track edit system
In contrast, the single-track edit system is a little more complex on the surface. The clips still overlap, but you can't see this overlap like you can in the A/B roll method. Instead, the clips are snuggled in behind each other (Figure 8.2 ). You can still manipulate the clips in the Trim Editor, but how you do this isn't quite as obvious as being able to see the overlapping gap between twp clips as is shown using the A/B roll system.
Figure 8.2. The top image shows the single track edit with hidden overlapping clips. Below this is a "side-on" graphical representation of that same image.

Figure 8.3. Two video clips are midway through a Dissolve, while over the top a title is coming to the end of a water drop transition.
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