If the opening credit is always the same with absolutely no change whatsoever (same exact video material, same titles,…), then the opening credit is considered to be the end product, and can then be used in any number of videos.
If there are small variations from one opening credit to another, then each will be considered a distinct end product and would each require a new license. However, if your videos are part of series, then the “series policy” comes into play. It allows you to use one license for up to 52 episodes or a year (whichever comes first).
Hope it helps