18 U.S. Code § 2387 - Activities affecting armed forces
(a)Whoever, with intent to interfere with, impair, or influence the loyalty, morale, or discipline of the military or naval forces of the United States:
(1)advises, counsels, urges, or in any manner causes or attempts to cause insubordination, disloyalty, mutiny, or refusal of duty by any member of the military or naval forces of the United States; or
(2)distributes or attempts to distribute any written or printed matter which advises, counsels, or urges insubordination, disloyalty, mutiny, or refusal of duty by any member of the military or naval forces of the United States—
Shall be fined under this title or imprisoned not more than ten years, or both, and shall be ineligible for employment by the United States or any department or agency thereof, for the five years next following his conviction.
(b)For the purposes of this section, the term “military or naval forces of the United States” includes the Army of the United States, the Navy, Air Force, Marine Corps, Coast Guard, Navy Reserve, Marine Corps Reserve, and Coast Guard Reserve of the United States; and, when any merchant vessel is commissioned in the Navy or is in the service of the Army or the Navy, includes the master, officers, and crew of such vessel.
https://www.law.cornell.edu/uscode/text/18/2387
The protection is greatest when speaking in the well of the House or on the floor of the Senate. It can extend to hearings held away from the Capitol, but there are limits. I think recording video for viral dissemination that is not a part of a Congressional function, especially when specifically citing the non-Congress credentials of the speakers as claims to authority, puts this in question. I do not think the Speech and Debate Clause of the Constitution applies. Others may differ.