DD5.1 means it features Dolby Digital 5.1 surround sound.
Troll (2022), a monster movie about a giant creature awakening in the Norwegian mountains. Troll.2022.PL.480p.WEB-DL.XviD.DD5.1-K83.avi
480p WEB-DL means it is standard definition (SD), sourced from a streaming service like Netflix. Troll.2022.PL.480p.WEB-DL.XviD.DD5.1-K83.avi