what aspect ratio, and on pc or mobile? It currently just shows the slide that covers the majority of the screen, which could be a bad assumption in certain cas

what aspect ratio, and on pc or mobile? It currently just shows the slide that covers the majority of the screen, which could be a bad assumption in certain cases. The videos are large by design, I just wanted them to look a bit better than youtube videos. The 4k versions are up to 20Mb, but I was hoping preloading the next two slides would help with that.