It is entirely possible to tag interactions with a player called via an iframe.
Any player has events you can interact with such as play or pause.
The tagging method used can vary depending on the player type.
There are specific plugins for YouTube, Brightcove and JW Player on our marketplace. All HTML5 players can be tagged using the method outlined in the documentation.
Flash players on the other hand cannot be tagged with SmartTag, as it is not available in ActionScript. If your player uses Flash, you will need to use xtcore.js (see the documentation).