Sync up elements

When designing your template, you'll often need certain elements to line up so they start and end at the same time. The key to achieving this is setting the right durations for each element to control exactly how they interact on the timeline.

Linking two elements

Let's look at a common scenario: combining a video with background music. You want the music to match the video's duration exactly, stopping when the video ends.

By default, both are on (Media) and take the length of their own file. The template is as long as the longest element inside it, so a music file that runs longer than Main-Video makes the whole template longer than the video.

Changing the music's duration to (Auto) fixes this. The music then has no length of its own, so the template takes its length from the video alone, and the music fills that time, ending exactly when the video does. Because the music follows the template rather than its file, it stays in sync when a longer or shorter video comes in.

Using compositions

The method above works well for simple scenarios. However, more complex templates, such as multiple scenes that each have their own voiceover, need a different approach.

A common mistake is to put the voiceovers one after the other on one track, and their video clips one after the other on another. The voiceovers link up, each starting where the one before it ends, but nothing ties a video clip to its voiceover. They only line up by chance: a shorter first voiceover moves Voiceover-2 up, while Video-Clip-1 keeps showing:

The solution is to group the elements that need to sync up, so that each group has a timeline of its own. Group Voiceover-1 and Video-Clip-1 into a composition Scene-1, and Voiceover-2 and Video-Clip-2 into Scene-2, then place the scenes one after the other on one track. Each scene, on "Auto", is as long as its voiceover, and its video clip fills it. A shorter first voiceover now makes Scene-1 and its clip shorter, and Scene-2 starts where Scene-1 ends: