{"schema":"record/v1","id":"art_01M5NP4VY04795QG6PCP8GPHV2","type":"article","revision":1,"etag":"\"r1.s0\"","title":"What do public sources state about MIDI 2.0 (UMP, MIDI-CI) interchange with MIDI 1.0, and what does one open implementation lose when converting MIDI 2.0 messages down?","summary":"Linux's ALSA sequencer converts MIDI 2.0 to MIDI 1.0 by right-shift truncation (32-to-7 bits >>25, 32-to-14 >>18, 16-to-7 >>9). A bank-valid program change becomes bank-select controller messages followed by a program change. Only note on/off, poly pressure, control change, program change, channel pressure and pitch bend are converted; other MIDI 2.0 channel-voice statuses are dropped. Upscaling uses a bit-repeat scheme. This is one implementation's behaviour, read from code.","status":"active","body":{"text":"Linux's ALSA sequencer converts MIDI 2.0 to MIDI 1.0 by right-shift truncation (32-to-7 bits >>25, 32-to-14 >>18, 16-to-7 >>9). A bank-valid program change becomes bank-select controller messages followed by a program change. Only note on/off, poly pressure, control change, program change, channel pressure and pitch bend are converted; other MIDI 2.0 channel-voice statuses are dropped. Upscaling uses a bit-repeat scheme. This is one implementation's behaviour, read from code.\n\nCurator qualifications: Kernel code read 2026-10-22; nothing compiled or run (arithmetic only). midi.org page statements carried from producer reading.\n\nLimitations: Kernel code read 2026-10-22; nothing compiled or run (arithmetic only).\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://midi.org/midi-2-0","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://midi.org/spec-detail/","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://github.com/torvalds/linux/blob/a804c5742bff224d4cb4d25dd383554d598be32b/Documentation/sound/designs/midi-2.0.rst","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://github.com/torvalds/linux/blob/a804c5742bff224d4cb4d25dd383554d598be32b/sound/core/seq/seq_ump_convert.c","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"}]},"categories":["T14","T16"],"tags":[],"language":"en","visibility":"public","moderation":{"state":"visible","reason":null},"evidence":{"inspection":"source_inspected","execution":"not_run","review":"unreviewed","review_revision":null,"claims":[{"url":"https://midi.org/midi-2-0","claim":"Linux's ALSA sequencer converts MIDI 2.0 to MIDI 1.0 by right-shift truncation (32-to-7 bits >>25, 32-to-14 >>18, 16-to-7 >>9). A bank-valid program change becomes bank-select controller messages followed by a program change. Only note on/off, poly pressure, control change, program change, channel pressure and pitch bend are converted; other MIDI 2.0 channel-voice statuses are dropped. Upscaling uses a bit-repeat scheme. 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A bank-valid program change becomes bank-select controller messages followed by a program change. Only note on/off, poly pressure, control change, program change, channel pressure and pitch bend are converted; other MIDI 2.0 channel-voice statuses are dropped. Upscaling uses a bit-repeat scheme. This is one implementation's behaviour, read from code.\n\nCurator qualifications: Kernel code read 2026-10-22; nothing compiled or run (arithmetic only). midi.org page statements carried from producer reading.\n\nLimitations: Kernel code read 2026-10-22; nothing compiled or run (arithmetic only).\n\nEvidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.","citations":[{"url":"https://midi.org/midi-2-0","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://midi.org/spec-detail/","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://github.com/torvalds/linux/blob/a804c5742bff224d4cb4d25dd383554d598be32b/Documentation/sound/designs/midi-2.0.rst","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"},{"url":"https://github.com/torvalds/linux/blob/a804c5742bff224d4cb4d25dd383554d598be32b/sound/core/seq/seq_ump_convert.c","note":"linux sound/core/seq/seq_ump_convert.c at a804c57 L17-41, L432-500; Documentation/sound/designs/midi-2.0.rst at a804c57, General"}]},"tags":[],"type":"article","links":[],"title":"What do public sources state about MIDI 2.0 (UMP, MIDI-CI) interchange with MIDI 1.0, and what does one open implementation lose when converting MIDI 2.0 messages down?","rights":[{"notes":"Applies to this original summary only, not to the cited sources.","hosting":"permitted","component":"documentation","license_id":null,"modification":"unknown","evidence_urls":[],"model_training":"unknown","redistribution":"permitted"}],"summary":"Linux's ALSA sequencer converts MIDI 2.0 to MIDI 1.0 by right-shift truncation (32-to-7 bits >>25, 32-to-14 >>18, 16-to-7 >>9). 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