feat(gp_autosync): piecewise time-warp helpers + refine_sync onset pass (#787)

* feat(gp_autosync): piecewise time-warp helpers + refine_sync onset pass

auto_sync computes per-bar sync points but consumers only ever applied the
scalar bar-1 audio_offset, so any tempo drift between the recording and the
tab's authored tempo accumulated over the song. Add the librosa-free helpers
needed to apply the full piecewise mapping:

- bar_start_times(gp_path): per-bar score times sharing auto_sync's axis
  (GPIF bar-resolution map, GP3/4/5 per-tick integration)
- build_warp_anchors(points, bar_starts): monotonic (score, audio) anchors
- warp_time(t, anchors): piecewise-linear map with edge-slope extrapolation
- warp_song_times(song, warp): retime a lib.song.Song in place (notes,
  sustains, chords, beats, sections, anchors, handshapes, phrase levels,
  tone changes, tempo overrides)
- gp_has_expandable_repeats(gp_path): detects GP3/4/5 repeat/volta/direction
  markup whose playback expansion auto_sync's as-written points cannot map

Also implement refine_sync() — the editor's refine-sync endpoint has imported
it since the snapshot but it never existed in lib, so the Refine button 500'd.
It densifies the DTW points to every Nth bar and re-times each with a local
onset phase sweep (radius clamped under half a beat to avoid one-beat locks,
short scoring grid + median residual snap against the first beats). Synthetic
click-track validation: ~13ms mean / ~40ms max error from ±180ms coarse input
across 117-123 BPM recordings of a 120 BPM tab.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* review: Copilot round 1 — normalize bar_start_times GP3/4/5 parse failures to ValueError, document ImportError

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Byron Gamatos
2026-07-05 20:08:19 +02:00
committed by GitHub
co-authored by Claude Fable 5
parent 74cff4e0d6
commit 92dc321fdf
5 changed files with 790 additions and 29 deletions
+1
View File
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
## [Unreleased]
### Added
- **`lib/gp_autosync.py`: piecewise time-warp helpers + a working `refine_sync()`.** `auto_sync()` has always computed per-bar sync points (DTW), but consumers could only apply the scalar bar-1 `audio_offset`, so any tempo difference between the recording and the tab's authored tempo accumulated audibly over the song. New librosa-free helpers expose the full mapping: `bar_start_times(gp_path)` (per-bar score times on the same axis as the sync points — GPIF bar-resolution map for `.gp`/`.gpx`, per-tick integration for GP3/4/5), `build_warp_anchors(points, bar_starts)` (strictly-monotonic `(score, audio)` anchor pairs), `warp_time(t, anchors)` (piecewise-linear map with edge-slope extrapolation for count-ins/tails), `warp_song_times(song, warp)` (retimes a `lib.song.Song` in place: notes + sustains, chords, beats, sections, anchors, handshapes, per-phrase difficulty levels, tone changes, tempo overrides), and `gp_has_expandable_repeats(gp_path)` (detects GP3/4/5 repeat/volta/direction markup whose playback expansion the as-written sync points cannot map — callers fall back to offset-only sync). Also implements `refine_sync()`, which the editor plugin's refine-sync endpoint has imported since the snapshot but which never existed in core (the Refine button 500'd): it densifies the coarse DTW points to every Nth bar and re-times each with a local onset phase sweep (sweep radius clamped under half a beat so periodic material can't lock a full beat off; short scoring grid + median residual snap). Synthetic click-track validation: ~13ms mean / ~40ms max error from ±180ms coarse input across 117123 BPM recordings of a 120 BPM tab. Tests: `tests/test_gp_autosync_warp.py`.
- **Playlist shuffle.** The v3 playlist detail page gains a crossing-arrows shuffle toggle next to Play all / Play album. When on, `playQueue.start` Fisher-Yates-shuffles the queue once at start (on a copy — the stored playlist order is untouched), swapping any per-slot album arrangements in lockstep so each slot keeps its pinned arrangement. The preference is global and persists in `localStorage` (`v3PlaylistShuffle`). Tests: `tests/js/play_queue_shuffle.test.js`.
### Changed