Video players fail to render

This is a solution to anyone having trouble getting their media players for YouTube, Brightcove, Vimeo or any other video format to appear or render from a token within a field. There are a number details that you have check to make sure tokenized nodes are displaying properly, such as formatting the fields of both the tokenized content and the container (or parent) content, configuring the view modes or "custom displays" for each, setting the CSS and any applicable template files, such as node.tpl.php. If you have done all these things, and everything renders EXCEPT for the video fields player, there is one last critical thing to check.

Don't forget to check the text format of the containing field. Nowadays we avoid an open Full HTML field format because of security issues. But if you use a filtered text format, you must make sure it allows for the HTML tag elements used in the video players. For YouTube it is the <iframe> tag. For Brightcove and some others it is the <object> and <param> tags. If you don't allow for these tags, then your players will mysteriously disappear from the rendered output.