Fixed frame rate ABS/OLA sinusoidal modeling applied to polyphonic music synthesis

This paper describes algorithms developed to implement the Analysis-by-Synthesis/Overlap-Add (ABS/OLA) sinusoidal modeling system in real-time polyphonic music synthesizer. As originally proposed, the ABS/OLA system is limited to unidirectional time-scaling, and relies on variable frame length to accomplish timescale modification. For MIDI-driven music synthesis applications, unidirectional time scaling makes effective looping to produce sustained notes difficult, and variable frame length makes real-time polyphonic synthesis problematic. This paper presents a reformulation of the ABS/OLA system to deal with these issues, which is termed Fixed-Rate ABS/OLA (ABS/OLA-FR).