By "speeding up the audio to fit over the remaining novel information", as I said. "B-roll" doesn't necessarily imply worthless stock-footage filler; in https://www.youtube.com/watch?v=woj4vfMLpao or https://www.youtube.com/watch?v=DdF_nzMW_i8 or https://www.youtube.com/watch?v=Eu_crbcBdNM, for example, the B-roll is the remaining novel information. The third of these also includes the kind of talking-head filler I'd like to remove.