For mouse events, these handlers were registered as capturing listeners on the document object because the user might have dragged outside of the video controls.  But with touch events, all events are delivered to the same element that the touchstart event is delivered to.  So, you can register these on the video controls, just like the touchStartHandler. And, since they're being registered on the same element, they don't need to be registered and unregistered. I think you can just register them at the same time as registering the touchstart handler.

Does that make sense? If not, ask me to clarify, please.

I don't understand your comment about why a capturing listener is required, but I wonder if it wouldn't be necessary if the handler was registered statically on the video controls instead of the document.