ad Orientem was the norm prior to the Second Council. Vatican II documents do not mention worship versus populum, by the way. Subsequent documents allowed it but did not mandate it and the GIRM still does not. However, versus populum was allowed - mention of it can be found in the 1625 missal - although most sources state it was rare and usually occurred out of necessity as a result of architecture such as in those Churches with a confessio.

while allowing the congregation to see and hear the priest is optimum

That remains in question as many contemporary celebrants consider themselves to be "performing" rather than humbly offering the Sacrifice and that causes many in the nave to not have the correct focus.

What is depicted in the film clip is not the new Mass. The clip is taken from an NBC documentary entitled "The New American Catholic," which aired in June 1968 (see the link below). The new Mass was promulgated in April 1969, almost 10 months later.

That particular portion of the film depicts the interim missal of 1967, not the new Mass, and is a sad reminder of what was experienced by those of us who lived through that era.

New Liturgical Movement: “The New American Catholic”: A Documentary from 1968

@DJRESQ Thank you very much for the link to the source documentary. Yes, while it is not the final "Novus Ordo", the interim missal had already introduced pretty cataclysmic changes. The Priest is already facing the people and he's offering the Mass in English (as can be heard in the soundtrack)....so quite a bit of disruption has taken place already. I can't imagine what a shock it was for faithful churchgoers at that time. All the stillness and mystery is gone; silent prayer made more difficult already. They don't look happy.

In those days, when things began falling apart fairly rapidly, the jarring nature of the changes depended on which diocese, bishop, parish, and/or priest was involved.

For example, Archbishop Lefebvre used that same missal of 1967 (no prayers at the foot of the altar, Mass began at the chair) until his seminarians, mainly Americans, urged him to return to the 1962 missal. Had he not done so, the traditional movement would probably look vastly different today. But obviously his Mass was sacred, even though he was using the interim missal. Others, such as some of the Masses depicted in the documentary, were definitely not sacred.

In the parish where I went to Catholic school, which was not considered progressive by any means, standing for the reception of Holy Communion was instituted in 1966, if I recall correctly (but definitely by 1967), Mass was completely in the vernacular by that year, and the priest began offering Mass facing the people in 1966 I think (can't recall exactly, but definitely by 1967). This was all prior to the Novus Ordo Missae, which the average Catholic had never even heard of.

The parish in the next town from where I lived began building a new church in 1964. It was a very modern structure, built with a freestanding altar so that the priest could offer Mass facing the people, and the tabernacle was in a side chapel. 1964.

It was, however, built with a Communion rail, which the parish stopped using almost immediately.

As an aside, my town and that one were hit by tornadoes that were part of the infamous "Palm Sunday Outbreak of 1965" (you can google it for details), and that parish's school and the old church were completely destroyed. It missed the new church. Shoulda been the other way around, lol.

Oh, yes, I was old enough to remember. I was a teenager when the new missal was finally published.

My parents are in their 90s and have always practiced the Faith and been very active in their parish. They accepted the changes, as they really had no other option. I never heard them complain in that regard. As for my siblings, the old Mass is merely a distant memory for them.

I have a very large extended family on both sides (aunts, uncles, cousins, et cetera). Out of all of them, only one of my uncles and his wife were not happy with the changes. He began attending a Maronite parish, and she stopped practicing the Faith altogether. Another of my uncles is a monsignor (now retired), and he had no problem with the changes.

I remember when my parents were upset with the guitar music. They have stopped that in our church now. Thank God.

If they start clapping in church to music my cult radar detectors ho off.;)