Potential structure: overview of AC3/Hindi music, sources (official vs. unofficial), technical aspects like file formats (AC3, MKV/MP4 containers), download methods (legal vs. illegal), and user considerations like audio equipment needed.
Possible challenges: Availability of Hindi 5.1 content might be limited. Most Hindi music is in stereo. Need to mention that 5.1 is more common in movies than standalone songs. Dolby Digital Ac3 5-1 Audio Hindi Songs -UPD- Download
Ethical and legal advice: encourage users to support artists by purchasing through legal channels. Maybe suggest creating playlists with legal sources to enjoy the sound. Potential structure: overview of AC3/Hindi music