After adding the transition effect to the arranged video, the overall time is shortened and does not match the lyrics. How to solve it?

It's really shortened. In a concert, if the transition is 1 sec, the last 1 sec of the previous material will be taken out, and the first second of the following material will be transformed. Because the length of the transition is 1 sec. Then the total length is -2+ 1=- 1, and of course 1 sec is missing. More generally, it may be easier for you to understand that there are two overlapping materials with such a long transition length, which is of course shortened. In premier, a traditional professional non-editing, this problem does not exist. By extending the material (but this method also has disadvantages. If the extended video has other content, the transition will be ugly). Therefore, the experienced PR is that if you want to use transitions, the head and tail of the material need not be old, leaving a little room. Let's go back to the question of sound and shadow. For convenience, the sound and shadow are not bad, because it doesn't matter if it is simply edited. But if you have special requirements and can't tolerate them, then you can do the same, and extend the transition length for the two materials as a whole in advance. After adding the transition, the transition length is reduced, which just offsets the transition length.