How exactly do video and e-learning products similar to Coursera, Udacity, etc. track the view progress of a user?

Question

I want to implement a system to track the how much has the user viewed a video. I am working on react, nodejs and mysql. I am able to record the amount of time of each session (a session being from (in milliseconds) and to (in milliseconds) when the video was played by the user). I am struggling to find the best condition where i can confidently say that the user has completely viewed the video. Is there any standard way to determine if a user has viewed the video completely? or a better way to track the progress?

Answer 1

Companies like the ones you mentioned usually use a third party ( such as mux or similar) to provide this service.

The way it works there, is the player software running in the browser is modified with a plugin to send state informant on an interval to a collection server, which aggregates this data and produces reports.

There is currently no standard format for the reported data, everyone does it differently.