HBO’s official Game of Thrones Youtube channel has uploaded a brand new video, featuring writer and editor Bryan Cogman (recently interviewed here regarding season 3) about the process of turning the books into the series. Cogman’s work entails providing the notes and outlines of the books that help serve as the underpinnings of the upcoming season, and it’s interesting to see that process described somewhat. Also, the video features some glimpses of season 3 filming, including a brief scene featuring Dame Diana Rigg as Olenna Tyrell, as well as other new cast members such as Ciarán Hinds as the King-beyond-the-Wall Mance Rayder (lacking, alas, his black cloak sewn with red silk) and Clive Russell as Ser Brynden Tully, called the Blackfish.