Abstract: A characteristic karaoke video-on-demand (VOD) system with a reference index database is provided. According to the reference index database as well as a song request signal inputted by a user, the characteristic karaoke VOD system is able to recommend at least one artist or at least one song to the user to enhance convenience and functionality offered by the characteristic karaoke VOD system.

Abstract: A situation command system including a multimedia apparatus and a server is provided. The multimedia device and the server are connected via a network system. The multimedia apparatus, including a microprocessor, a memory device, a multimedia file input device, a network interface, an audio/video body-sensing input device, an audio/video body-sensing output device and a control device, presents a multimedia effect of a file to a user. The server, including a central processing system, a storage system, a communication system and a recognition system, accesses the file and determines whether the file satisfies a trigger condition to selectively output a special effect. When the file satisfies the trigger condition, the multimedia apparatus further superimposes the special effect to the file and presents the file together with the special effect to the user to provide a situation simulation effect.