Some purists argue that Batman Begins demands 5.1 audio for the full theater experience. While true for English, consider the reality of Hindi dubbing:
"DD20" stands for Dolby Digital 2.0. This is a fascinating detail. In an era of 5.1 and 7.1 surround sound, a 2.0 stereo track might seem outdated. However, in the context of a Hindi-dubbed bootleg, it makes sense:
The search term includes "2005 Bluray," which is crucial. When Batman Begins was released on Blu-ray, it was a transformative moment for home cinema. Nolan and cinematographer Wally Pfister shot the film on anamorphic 35mm film, giving Gotham a dense, shadowy texture that standard definition DVD could not capture. The Blu-ray transfer, particularly the later remastered editions, brings out the nuanced grain of the film stock. The dark alleys of the Narrows, the icy peaks of Bhutan, and the polished chrome of the Tumbler (the Batmobile) are rendered with a clarity that reveals production design previously lost in compression.
However, the most telling part of your query is "Hindi DD20" —Hindi Dolby Digital 2.0 stereo.