30 odd years ago. Programmers saw that basing music on small, pitch shifted, samples could save a lot of resources. So "Tracker" players were created and developed. These were based on a trimmed version of how MIDI worked.
Today, there is no longer a need to trim the MIDI standard, and so we can keep the advantages of interoperability together with custom quality of pitch shifted samples. Also we can blend samples from different frequencies and then envelope the results for even better results.
MIDI files on computers suffered from some bad sounding implementation in the past and as such lost some popularity in some sectors. However, in the music profession it is the defacto standard for good implementations.
Instead of transferring huge audio tracks, we can just send short samples (or none at all and calculate them) and play them at extremely low computational cost. Realistically you can reduce the footprint of your audio media sizes by factors of 100 or more! Obviously this is not a fit for all cases, but you may be surprised how far it can fit. It also offers the ability to nicely bridge between tracks which can be a useful effect.
SongForge started life as a tracker in the 90's. It awoke in 2014 in the form of a mobile app and Unity engine for a few games (more of a game utility than anything else).
Now, 2024, awoke again it is transformed into into something far more musical. It is getting super-charged and supports the web natively.