The HTML5 Video Tracking tag assumes that there is a title attribute present on the <video> element, however in the case of Wistia this is not true. There is no way, using Wistia’s embed code, to include a data-video-title attribute.
Wistia injects JSON+LD in the <head>, and that is where the video title is rendered. Example:
Might I suggest that rather than assuming an HTML attribute to fetch the title, we modify to either allow a variable OR a CSS selector for the title? This would still allow the HTML title attribute to be used if present, but also allow for more flexibility around where the title is fetched from.
In the case of JSON+LD, the title can be accessed using: