Slideshow made in Photos app being very choppy, not smooth
I made a slideshow containing photos and trimmed videos in Photos app on my iMac. When I exported the slideshow, the transitions between the slides are not as smooth as the preview and some videos (not all of them) are very choppy. How can I fix the problem keeping the best or better quality of the videos and photos? Some of them were taken with Android phone and iPhone, and the rest were taken with my reflex camera, if that helps. Thanks!