How a transition shortens your edit and moves captions

A transition changes the length of your video. It overlaps the two clips on the main track by its Duration, so the incoming clip starts that many seconds before the outgoing clip ends. Both clips play their real footage across the overlap. Nothing is borrowed from trimmed footage, so each blend removes its own length from the edit.

The arithmetic

Each transition takes its Duration off the total length of the edit.

• At the starting length of 0.50 seconds, four transitions make the edit two seconds shorter.
• Dragging the Duration slider moves everything after the cut as you drag. A longer Duration shortens the edit more, and a shorter one gives time back.
• The overlap is capped at 90 percent of the shorter clip, so a blend can never swallow a clip. A short clip, such as a photo set to a brief length, can overlap by less than the slider shows.
• Deleting the transition returns the time. The later clip slides back out by the length of the old overlap.

What moves

These move earlier by the overlap when they sit after the cut (clips on upper video tracks stay where they are):

• The clips later on the main track.
• Titles that start at or after the start of the incoming clip.
• Captions that start at or after that point, with their word timing.
• Soundtrack clips that start at or after that point.

A title or caption that starts before the cut and ends after it keeps its start, and its end moves earlier, so it becomes a little shorter.

What stays put

Sound moves by its start alone. A long music or narration clip that begins before the cut stays where it is, while the picture after the cut arrives earlier. Past the cut, the sound runs later than the picture by the overlap.

Two sound clips in a row can collide. If a clip that starts after the cut moves earlier and lands on the end of the clip before it, the earlier clip gives up its tail where they meet.

Check the result

1. Add the transitions you want.
2. Play across each one, starting a few seconds before it.
3. Watch each caption and title that sits near the cut and confirm it lands on the right words.
4. Listen to any narration or music that spans the cut and confirm it still lines up with the picture.
5. Move or trim a sound clip that has drifted.

Plan for the shift

Add transitions before you place the pieces that depend on exact timing: the narration, the music hits and the titles. The footage settles first, and the timed elements follow it. When a transition has to come late, expect to nudge everything that spans the cut.

If the final length matters, for example a video that must fit a time limit, read the length after the last transition. The total can only get shorter as you add blends.

Watch one caption move

Open DepCut, note where a caption sits near one cut, and add a Cross fade and set its Duration to about 1 second. Play the cut and watch how far the caption moved.