Thanks for posting to the Hub!
Prior to C-SPAN, the U.S. House and Senate rarely recorded proceedings and any footage belonged to the broadcasting company--not Congress. I suggest contacting repositories such as the Film and Television Archive at UCLA or the Vanderbilt Television News Archives.
My office, the Center for Legislative Archives, holds the unpublished committee records of the U.S. House and Senate. We have very little audiovisual material in our committee records; however, it's possible early audiovisual records were transferred to NARA's Motion Pictures unit. You can search the NARA Catalog for video footage. You can access more recent video footage of U.S. House and Senate proceedings through the Library of Congress: Congressional Floor Proceedings.
If you have any questions concerning unpublished congressional records, I suggest contacting an archivist at firstname.lastname@example.org.
I hope this information is helpful!