Chord-progression ground truth

140 progressions · 2,800 song rows · 1338 trusted calibrations · built 2026-08-08 02:03

select a progression on the left

Definitions — a progression is a key-free shape of 4 consecutive chords (interval-from-first-root + quality), spelled here rooted at C: “A B F♯m A” and “C D Bm C” are the same row. Song order = occurrences, then coverage (share of the song's chord windows matched) — both printed. Spans are tab-clock, mapped to video time by per-song measured audio alignment (video_t = a·tab_t + b, 2 s lead-in). Badges: SYNC Songsterr's own tab↔video sync — their curated video, video time of every tab measure, interpolated per occurrence (semantics verified against an independent audio alignment: 0.46 s median divergence) · CAL✓ certified — measured, uniform, no pitch shift, sharp correlation peak (psr ≥ 2); on the tier-A duplicate bench this gate hit the right start second in 26 of 28 pairs (92.9%), 1/63 wrong-video accepts · CAL measured, uniform, no pitch shift (bench: 43/52 = 82.7%) · ROUGH low-confidence fit, start shown but untrusted · UNCAL not yet aligned, raw tab time · NO VIDEO nothing to embed · VIDEO REMOVED dead on YouTube, no calibration-verified replacement found (a search link is offered) · replaced = dead link swapped for a calibration-verified alternative. Two-chord oscillations (C5–G5–C5–G5…) are real and popular but live on their own tab; single-chord drones are excluded. Open this page through START_SITE.bat (http://localhost:8813) — YouTube requires an http referer for embedded playback, so file:// shows player error 153 on every video. Verdicts stay in this browser (localStorage) until exported.