FA-81499 / MIDI event timing / Member archive

Set Tempo meta event to BPM: declared length of the tempo event not checked · case 04

A malformed Set Tempo event declaring length 4 or 2 is accepted as if it were valid.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input the bytes of a Set Tempo meta event: FF 51 03 followed by a 24-bit big-endian microseconds-per-quarter value (nonzero). Return [microseconds, bpm_x100] where bpm_x100 = 6000000000 / microseconds rounded half up. Anything else 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	`[500000, 12000]`	`null`	Failed

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