FA-78689 / Broadcast timecode arithmetic / Member archive

Audio sample to frame cadence at 48 kHz: ntsc rate table · case 04

Sample cadence for 29.97 video slowly slips against the true 30000/1001 rate.

Member previewVariant 4 · 3 implementations · 9 checks per implementation

Case contract

At 48000 samples per second and rate N/D, the frame containing sample s is floor(s*N/(48000*D)); frame k starts at sample ceil(k*48000*D/N). Return [frame, offset of s inside its frame, number of samples in that frame].

Why this case matters

Timecode arithmetic errors misplace edits, commercial breaks and captions against the broadcast clock.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: ntsc rate table	`[3663, 1238, 1602]`	`[3663, 1244, 1602]`	Failed

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