JackTrip
Stanford software that sends uncompressed multichannel audio over the internet with low enough delay for musicians in different places to play together.
JackTrip came out of Stanford's CCRMA around 2007–2008, with Chris Chafe and Juan-Pablo Cáceres as the main developers. The idea is to skip compression altogether: raw PCM goes straight into UDP packets, because codecs add delay and a dropped packet beats a late one. It was originally built on JACK, hence the name.
Physics sets the limit. Light in fibre covers roughly 200 km per millisecond, and about 25 ms of latency is what musicians tend to tolerate before the ensemble starts to drag. That's enough for a city or a country, not a continent. In spring 2020 the pandemic turned JackTrip from a research tool into a lifeline for choirs and bands.