A system for automatically manipulating prerecorded audio data to produce an audio track synchronized to a target video track. The system allows a user to select a music source from multiple music sources stored in a music library. Each music source includes multiple audio portions having block data and beat data associated therewith. The block data includes data blocks respectively, specifying the duration of the associated audio portions. Each data block preferably also includes interblock compatibility data and/or suitability data. The beat data, generally referred to as a “beatmap”, comprises timing information specifying the rhythmic pulse, or “beat” for the associated music source portion. The system is operable to produce an audio track synchronized to a video timing specification (VTS) specifying successive timing segments delimited by successive video events. After the user selects a music source, the system generates a music segment for each defined timing segment. Each music segment is generated by assembling an ordered sequence of compatible data blocks selected at least in part based on their suitability and/or compatibility characteristics.