There are many sites recently that allow teachers to add questions to a video to gauge comprehension: EdPuzzle and Zaption are two off the top of my head.
If you have ever wanted to stay within the Google ecosystem for this type of assessment, you can use Google Forms.
One way to do this is to insert a video from YouTube (or another hosting site) and link to it. The easiest way is to place the whole clip in the form and add questions after it. The quiz can then be graded using Flubaroo.
If the video is long, you can use the YouTube Video Editor to cut down your video into clips depending on the video’s license.