Hah! You should have paid closer attention to that video. It's not even AI. It's just fake. I asked at Google, though you can easily see that whatever they're singing wasn't Sound of Silence. The recording of the song the the original, by Simon and Garfunkel.
The Beatles never recorded or performed a cover version of Simon & Garfunkel's "The Sound of Silence." While both groups were active in the mid-1960s, their musical paths and recording catalogs did not overlap in this manner.
Original Artist: "The Sound of Silence" was written by Paul Simon and released by Simon & Garfunkel in 1964.
Context: The Beatles were famously influenced by Bob Dylan's acoustic sound during this period, but they did not cover this specific Simon & Garfunkel hit.