Note that the bassist (Wes Wehmiller) is using a five string.
For the main (verse) riff, I think the root notes are D (A5) to Bb (E6) to A (E5) on 1, 2, 3 and then F (E1) and G (E3) on the 4 & count. There are octave and fifth jumps in there as well.
In the chorus, I think the progression is D (A5) to G (D5) to C (G5) to F (D3).
The main riff sounds really cool in Drop D using the open D string for the D, then the rest of the notes (Bb, A, F, G) on the same string.