jFonia is a framework/API for music, focusing on symbolical (discrete) data such as notes, clefs, measures etc.
It is a low level framework, aiming to facilitate the development of high level music software, such as score players, viewers, editors, analysis and composition tools etc.
P. Schaer, T. Breuer, L. Castro, B. Wolff, J. Schaible, and N. Tavakolpoursaleh. Experimental IR Meets Multilinguality, Multimodality, and Interaction. Proceedings of the Twelfth International Conference of the CLEF Association (CLEF 2021), volume 12880 of Lecture Notes in Computer Science, (2021)