Hollywood studios heavily rely on international markets, and India is one of the largest. A "Dual Audio" file contains two or more distinct audio tracks multiplexed into a single video container (usually an .mkv file).
It's the dedication of artists like these that transform a Hollywood blockbuster into a film that feels local, earning the Hindi-dubbed version the reputation of being a masterpiece in its own right. i am legend 2007 hindi dual audio 720p bluray portable