Does the HTML5 SDK support closed captions for video? Is the format of captions for the HTML5 SDK the same as for the AS3 viewer?
Support for closed captions was added to the HTML5 SDK in 2013 for this. For more information, see
http://help.adobe.com/en_US/scene7/using/WS98ca2e6790647c06-6f6f53e137b959f094-8000.html
HTML5 captioning isn't the same as for the AS3 viewer. There are no current plans to unify HTML5 captioning with the existing Flash-based caption support that exists today.