Edpuzzle is a platform that allows you to find and create video-based activities that include formative assessment by embedding text/audio notes and checks for understanding at any point during the video. It also enables you to trim video files to avoid spending more time than necessary finding the right place. These can be assigned to students to complete both in and out of class. Once completed, you have instant access to the formative assessment data.
As posted by UMassEDU under "Assessment-Centered Tools." Includes excellent screenshots, instructions, and links to more resources to help you learn and get comfortable using EdPuzzle.