By 2012 (when Shameless Season 2 aired), XviD was becoming an "old-school" format. While high-definition (H.264) was becoming the standard, scene groups like DEMAND continued to release XviD versions to ensure compatibility with older hardware, like standalone DVD players with USB ports.
More about how these older scene releases worked? Watch Shameless US S02E11 BDRip XviD-DEMAND
The title refers to Thanksgiving, and the "feature" of the episode is the subversion of traditional holiday tropes, replacing a peaceful meal with one of the most chaotic family breakdowns in the show's history. By 2012 (when Shameless Season 2 aired), XviD
If you are looking for an interesting feature regarding the of Season 2, Episode 11: The title refers to Thanksgiving, and the "feature"
Even though the file is compressed into an .avi container using XviD, being a "BDRip" means the source material was the highest possible quality available (Blu-ray), resulting in a cleaner image than a "HDTV" rip taken from a cable broadcast. Episode Context: "Just Like the Pilgrims Intended"