YouTube captions

When using YouTube as source for a video in "interactive video" and the video contains captions, the user can turn them on or off and also switch to any language that's available.

For not cluttering the user interface, there will only be one additional button (e.g. labeled CC) that reveals a list of languages and the additional option "off" at the top. The list could use the same look and feel as the QualityChooser.