vooPlayer is a fully responsive player and that means that it adapts to the size of the element in which you place it on your page.
This means that if the element in which you place vooPlayer is hidden by default, for example in a collapsed accordion or inactive tab, or any similar occurrence then vooPlayer will adapt to the size of the element as is on page load.
vooPlayer can't listen for activty on your page as that would violate many security and privacy principles so you need to let it know when an event has occurred which unveils or shows the video.
You do so by simply triggering the function forceVooplayerResize.
Doing so will force all the vooPlayer videos on the page to readjust to their parent elements as they are rendered at the time of the function being triggered.
So if you have the capacity to determine when an accordion has shown or tab opened, by for example detecting click events on their respective navigation elements, you can subsequently call the forceVooplayerResize function.
Keep in mind that most of these usecases have some sort of a show / hide animation which has delays which will require you to set a timeout on executing the resize function.
If you continue to experience difficulties with the proper sizing of vooPlayer, our support team is here to help.