The Universal MIDI Packet is one container for all MIDI, adding 16 Groups of 16 channels (256 total) and jitter-reduction timestamps

The Universal MIDI Packet (UMP) is a single data container that carries both MIDI 1.0 Protocol and MIDI 2.0 Protocol messages, intended for use across any transport that officially supports it. It expands MIDI’s addressing by adding 16 Groups, each containing its own independent set of System Messages and 16 Channels equivalent to MIDI 1.0 channels — so the addressable channel count rises from 16 to 256 (16 x 16). UMP also adds a Jitter Reduction Timestamp that can be prepended to any message for improved timing accuracy, and includes a large reserved space for future messages. Using UMP requires UMP Endpoint discovery to be enacted first, and it only runs over MIDI 2.0-capable transports.

Examples

A MIDI 2.0 host addresses instruments across several Groups, giving 256 channels instead of 16; a jitter-reduction timestamp prepended to note messages tightens their timing on playback.

Assessment

How many addressable channels does UMP’s 16-Groups structure provide, and how is that number reached? What does the Jitter Reduction Timestamp mechanism do, and what must run before UMP features can be used?