A multimedia platform records a performance on a keyboard synchronously with a picture by periodically regulating an internal clock, which is indicative of the lapse of time, with time codes inserted into the set of video data codes representative of the picture, and reproduces the performance through an automatic player piano also synchronously with the picture by periodically regulating the internal clock with the time codes, whereby the user enjoys himself or herself in the performance as if he or she feels himself or herself performing in a convert hall.