Smack has implemented XEP-0004: Data Forms version 2.9 standard.
However in XEP-0158: CAPTCHA Forms documents, its defined stanza may contain media element i.e. XEP-0221: Data Forms Media Element in the Form Field of the Data Forms.
Each CAPTCHA field MAY contain a media element (see Data Forms Media Element (XEP-0221) ) that in turn contains a pointer to media that the sender shall use in solving puzzles, performing optical character recognition, identifying audio or video samples, etc.
Current implemented Data Forms extension in Smack does not provide a way to retrieve the media element from the form field. Appreciate if smack team would consider adding the support to allow app to retrieve the media element for processing.