I began my process by auditing the existing video player.
Accessibility was a major issue. Users found it particularly hard to tap buttons on small mobile devices. This was because controls were undersized and crammed into corners of the screen. Essentially, the desktop UI was lazily scaled down to mobile with no regard for touch. Furthermore, there was little regard for the organization of controls into logical groups.
I researched competing video players such as YouTube, Facebook, Dailymotion, Streamable, and Twitter. I made note of layouts, button sizes, animations, gestures, and other ways these video players were designed to delight on mobile.
Finally, I created wireframes at a wide range of breakpoints with improved touch targets.