The player

Keys, speed, the A–B loop and timeline thumbnails.

On a computer, the player's keys work anywhere on a scene's page, as on YouTube: Space or K to play and pause, J and L (or ← and →) to go back or forward 10 seconds, 0 to 9 to jump through the video, < and > for slower and faster, M to mute and F for full screen. Press ? to see them all.

The buttons at the top left of the player choose the speed, and A–B plays part of a video over and over: press it where the part starts, again where it ends, and once more to stop.

Rest the pointer on the timeline, or drag along it, to see frames from that part of the video. x4u makes these in the background after previews; opening a video that doesn't have them yet makes its own within a minute, and Settings → Library can make all the rest now.