Given the size and power of the Baby Boomers demo, it’s a wonder the whole of TV isn’t back to back classic rock documentaries. But there are actually quite a lot of them.

The most annoying of the lot are like “Icon: Music Through the Lens” (PBS, 9 p.m.), an exhaustive and exhausting six-hour (!) celebration of the rock photographers who brag about the work they’ve done, repeat the same points over and over (“It’s about capturing a moment”) and use the word “iconic” to mean “a picture I did that I remember.” Perhaps because it’s Brit-centric, none of the images held up as iconic actually are. Like me, you may have never even seen many of them before.

For all their celebration of rock stars, they’ve neglected to license much of their music, so generic music plays underneath the boasts and florid remembrances.

One guy who has stayed remarkably humble despite making music that actually is iconic is Paul McCartney, whose television appearances can be wanting. Even so, it looked like his 2018 Carpool Karaoke with James Corden would ever be topped.

But now comes the unexpected delight of “McCartney 3,2,1” (Hulu, streaming), a black and white document of the meeting of the former Beatle with famed and supremely bearded producer Rick Rubin to dissect the old songs.

Mulling over the Beatles oeuvre on a mixing board so that individual tracks can be isolated is something their producer George Martin did on a public TV series a decade or so back.