I was going to look up C++ libraries to show canned videos that I’d like to include in my game, but then thought I’d first ask here for either advice from your experiences or perhaps even see if there’s a cocos2d-x solution.
There is a working implementation in the cocos2d-x fork, axmol, specifically in this directory. You may be able to port it across to cocos2d-x v3.17, or at least get some ideas on how to accomplish what you need.