lack of voices (polyphony) leads to errors / undefined behavior in some metrics

[lmartak]

When a midi file doesn't contain enough voices / polyphony, it leads to errors in articulation and dynamics metrics.

Introduction of an "empty voice" addresses the issue for articulation metrics, but the same trick doesn't amount to a complete solution for the dynamics metrics.

Perhaps a different workaround / definition of the dynamics metric is needed for such special case (lack of voices in one of the midi files).

This notebook to reproduces the issue using a monophonic midi file.

[huispaty]

Hi Lukas! Thanks for reporting the bug! I’ve added a fix in the same branch where you posted the issue—could you check if it works for your case? I tested it with the provided test file, but let me know if you run into any issues. If all looks good, I’ll add an official test and create a PR. Thanks!