I sourced out some video of the same, which can be viewed here: Pope Re-dedicates Monte Cassino
While we are on this topic of archival footage, efootage.com has numerous other short clips involving papal liturgy and ceremonial -- some of them rather rare.
For example, here is Pope John XXIII blessing the Wax Agnus Dei. (You can read more about this here.)
As well, we have video footage showing Funeral rites in St. Peter's Basilica.
Further, while we are accustomed to seeing blessings from the balcony of St. Peter's, something you don't see every day is a papal blessing from Santa Maria Maggiore: Pope Pius XI Blesses the World.
Finally, some other random bits of footage:
New Cardinals Elevated
Vatican Mourns Pope Pius XII
Canonization of Pope Pius X
Paul VI Celebrates Holy Week
John XXIII Canonizes Vincent Pallotti
Paul VI Marks First Anniversary
18th Anniversary of Pius XII's Elevation to the Papacy
3rd Anniversary of John XXIII
Ecumenical Council Re-opens