@windjc According the to the Purple Book Page 110 released from the College board.
References guidelines are as follows:
2e. Provide a list of at least three online or print sources used to create your computational artifact and/or support your responses through in-text citation to the prompts provided in this performance task.
At least two of the sources must have been created after the end of the
previous academic year.
For each online source, include the complete and permanent URL. Identify the
author, title, source, the date you retrieved the source, and, if possible, the
date the reference was written or posted.
For each print source, include the author, title of excerpt/article and magazine
or book, page number(s), publisher, and date of publication.
If you include an interview source, include the name of the person you
interviewed, the date on which the interview occurred, and the person’s
position in the field.
Include in-text citations for the sources you used.
Each source must be relevant, credible, and easily accessed.
My interpretation of the guidelines is that they prefer print or written sources. I agree with your premiss and @anmrobnott $0.02 that videos should be allowed as a credible resources. However, since the decision makers have not made an amendment or answered the question, I would encourage your students to use video as a final option if there are no up to date written sources.