It was the sound of a footfall in a room with no floors that moved.
As for the "Dual Audio 720p Download", it seems that you are referring to a specific version of the film that has been ripped and made available for download. The term "dual audio" typically refers to a version of a film that includes two audio tracks, often in different languages. In this case, it is likely that the film is available with English and possibly another language audio track. The Autopsy Of Jane Doe Dual Audio 720p Download