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+# MIDI Multicast
+
+Broadcast and synthesise MIDI over UDP.  The advantage of a connectionless
+protocol is that multiple servers and clients are easily supported, and the
+clients can be started while the servers are off.
+
+## Development
+
+Run `nix develop` for a development environment.
+
+Inside it, run `make`.  `src` must point to the source code, and `out` must
+point to where the build artefacts should be placed.  For example:
+
+```sh
+make src=. out=bin
+```
+
+## Compilation
+
+Run `nix build`.
+
+## Options
+
+Options are passed through environment variables.
+
+### Common
+
+- `MCAST_GROUP`: The UDP multicast address.
+- `MCAST_PORT`: The UDP multicast port.
+- `DEBUG`: Increase verbosity.
+
+### Client
+
+- `RELAY_DELAY`: The intended delay in milliseconds between the time a message
+  is sent and played.  Increasing it reduces stuttering but increases latency.
+  Both the client and server should have synchronised clocks.
+
+- `SOUNDFONT`: The path to the sound font for synthesis.
+
+### Server
+
+- `MIDI_IN`: The name of the MIDI input in ALSA.