FA-81457 / MIDI event timing / Member archive

Absolute events to delta-time serialisation: deltas written as absolute ticks · case 02

Every event after the first carries its absolute tick as a delta, so playback drifts later and later.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Input a list of [tick, kind, note] with kind on or off in any order. Emit events sorted by tick; at equal ticks note-offs precede note-ons, and otherwise input order is kept. Each output is [delta from the previous emitted event (the first from tick 0), kind, note]. A negative tick returns None.

Why this case matters

MIDI sequencers, file readers and synth drivers depend on exact event ordering and tick/time arithmetic.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
oracle 1	`[[0, "on", 60], [10, "off", 60], [10, "on", 62]]`	`[[0, "on", 60], [10, "off", 60], [0, "on", 62]]`	Failed

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