feat(midi): extract lyric meta-events and vocal melody into sidecar payloads

MIDI import previously ignored lyric meta-events entirely, so karaoke
MIDI files lost their lyrics and vocal melody on import.

- new extract_midi_lyrics(midi_path, audio_offset): returns spec 7.1
  lyrics + spec 7.2 vocal_pitch payloads, or None when the file has no
  usable lyrics (existing behavior unchanged)
- collects 0x05 Lyric events, with 0x01 Text as a conservative fallback
  on vocal-ish / Words / Karaoke tracks only (avoids importing copyright
  notices as lyrics)
- .kar conventions handled: '/' and '\' line-break prefixes fold onto
  the previous syllable as 7.1 '+'; '@'/'%' metadata dropped
- per-stream word conventions: hyphen-delimited streams pass '-' joins
  through; space-delimited streams synthesize joins; whole-word streams
  get none; line ends become trailing '+' (stripping a '-' first)
- melody pairing: greedy time-ordered, one note per syllable within
  0.30s; paired syllables snap t/d to the note so both sidecars stay
  mirrored per 7.2; unpaired syllables remain lyrics-only (spec-legal)
- vocal-track selection mirrors the GP importer's idiom (name keywords
  + GM programs 52-54/85-87); SMF type 0 isolates vocal-program
  channels, type 1/2 trusts the lyric-carrying note track
- unpaired lyric durations run to the next syllable, clamped 0.1-2.0s

Callers (the editor plugin's import flow) wire the payloads into the
pak in a follow-up; no manifest keys are written here.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: ChrisBeWithYou <chris@rifflarr.local>
This commit is contained in:
ChrisBeWithYou
2026-07-23 00:33:36 -05:00
co-authored by Claude Fable 5
parent 8297afc449
commit c86b2c8850
2 changed files with 718 additions and 2 deletions
+436 -2
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@@ -1,6 +1,6 @@
"""MIDI file import — list tracks and convert tracks to sloppak payloads.
Two parallel flows live here:
Three parallel flows live here:
- **Keys path** (`list_midi_tracks` + `convert_midi_track_to_keys_wire`):
filters channel-9 out and emits a standard guitar-style arrangement that
@@ -11,12 +11,19 @@ Two parallel flows live here:
`docs/sloppak-spec.md` §5.3, ready to drop alongside the sloppak
manifest's `drum_tab:` key.
The editor's track picker uses both for the +Drums and +Keys modals.
- **Lyrics path** (`extract_midi_lyrics`): reads SMF Lyric (0x05) meta events
(with a Text-event fallback on vocal-ish tracks, covering karaoke `.kar`
files) and emits the `lyrics.json` / `vocal_pitch.json` sidecar payloads
documented in feedpak-spec §7.1 / §7.2, ready to drop alongside the
manifest's `lyrics:` / `lyrics_source:` / `vocal_pitch:` keys.
The editor's track picker uses the first two for the +Drums and +Keys modals.
"""
from __future__ import annotations
import math
import re
from bisect import bisect_right
from collections import deque
from typing import Callable
@@ -777,3 +784,430 @@ def convert_drum_track_from_midi(
],
"hits": out_hits,
}
# ── Lyrics + vocal-melody extraction ─────────────────────────────────────────
# Vocal-track detection, mirroring the idiom in `lib/gp2rs_gpx.py`'s
# `_is_vocal_track` (GM voice/choir/lead-voice programs + name keywords).
# Kept as a local copy because that helper consumes gp2rs_gpx's own GP track
# dicts, not raw MIDI tracks. "melody" is added to the name hints: karaoke
# MIDIs commonly label the sung line "Melody" rather than "Vocals".
_VOCAL_MIDI_PROGRAMS = {52, 53, 54, 85, 86, 87} # Choir Aahs, Voice Oohs, Synth Voice, Lead 5-7 (voice)
_VOCAL_NAME_HINTS = ("vocal", "voice", "vox", "sing", "lyric", "choir", "melody")
# A dedicated karaoke *text* track (SMF 0x01 Text events, `.kar` convention)
# is usually noteless and named "Words" or "Soft Karaoke" — names the vocal
# hints above don't catch. Only the Text-event fallback consults this wider
# set; note-track detection sticks to the gp2rs_gpx idiom.
_LYRIC_TEXT_TRACK_HINTS = _VOCAL_NAME_HINTS + ("words", "karaoke")
# A lyric event pairs with a vocal note-on when their onsets sit within this
# window. Karaoke files place the lyric event at (or a hair before) the
# note-on tick, so real matches are ~0; the window only absorbs sloppy
# authoring, and staying well under a typical syllable gap keeps a melisma's
# extra notes from being stolen by the next syllable.
_LYRIC_PAIR_TOLERANCE_S = 0.30
# Duration bounds for lyric entries with no pairable note (spoken lines,
# lyrics-only files). "Until the next lyric event" is the natural display
# duration, capped so a verse-final syllable before a long instrumental
# break doesn't linger on screen, and floored so simultaneous/out-of-order
# events can't produce a zero or negative duration.
_UNPAIRED_LYRIC_MAX_D = 2.0
_UNPAIRED_LYRIC_MIN_D = 0.1
# Leading/word/trailing whitespace splitter for lyric tokens. DOTALL so
# embedded newlines land in a group rather than killing the match.
_LYRIC_TOKEN_RE = re.compile(r"^(\s*)(.*?)(\s*)$", re.S)
def _scan_tracks_for_lyrics(midi: mido.MidiFile) -> list[dict]:
"""One pass per track collecting the raw material `extract_midi_lyrics`
needs: name, per-channel programs, melodic (non-drum) notes with their
on/off ticks, and Lyric/Text meta events.
Each item: {name, channel_programs: {ch: program}, notes:
[(start_tick, end_tick, pitch, channel)], lyric_events: [(tick, text)],
text_events: [(tick, text)]}. Note pairing uses the same FIFO
note_on/note_off matching as the keys converter so retriggers don't
cross-wire durations.
"""
out: list[dict] = []
for track in midi.tracks:
name = ""
channel_programs: dict[int, int] = {}
lyric_events: list[tuple[int, str]] = []
text_events: list[tuple[int, str]] = []
notes: list[tuple[int, int, int, int]] = []
active: dict[tuple[int, int], deque[int]] = {}
abs_tick = 0
for msg in track:
abs_tick += msg.time
if msg.type == "track_name" and not name:
name = msg.name or ""
elif msg.type == "lyrics":
lyric_events.append((abs_tick, msg.text or ""))
elif msg.type == "text":
text_events.append((abs_tick, msg.text or ""))
elif msg.type == "program_change":
ch = int(getattr(msg, "channel", -1))
if ch != 9 and ch not in channel_programs:
channel_programs[ch] = int(msg.program)
elif msg.type == "note_on" and int(getattr(msg, "velocity", 0)) > 0:
ch = int(getattr(msg, "channel", -1))
if ch == 9:
continue
active.setdefault((ch, int(msg.note)), deque()).append(abs_tick)
elif msg.type == "note_off" or (
msg.type == "note_on" and int(getattr(msg, "velocity", 0)) == 0
):
ch = int(getattr(msg, "channel", -1))
pitch = int(msg.note)
stack = active.get((ch, pitch))
if not stack:
continue
start_tick = stack.popleft()
if not stack:
active.pop((ch, pitch), None)
notes.append((start_tick, abs_tick, pitch, ch))
# Close anything left hanging at end-of-track, mirroring the keys
# converter's end-of-track sweep.
for (ch, pitch), starts in active.items():
for start_tick in starts:
notes.append((start_tick, abs_tick, pitch, ch))
notes.sort(key=lambda n: n[0])
out.append({
"name": name,
"channel_programs": channel_programs,
"notes": notes,
"lyric_events": lyric_events,
"text_events": text_events,
})
return out
def _name_matches(name: str, hints: tuple[str, ...]) -> bool:
name_l = (name or "").lower()
return any(h in name_l for h in hints)
def _normalize_lyric_tokens(events: list[tuple[int, str]]) -> list[dict]:
"""Turn raw lyric/text meta events into clean syllable tokens.
Handles both encodings seen in the wild:
- **`.kar` / karaoke convention**: `/` prefix = new line, `\\` prefix =
new paragraph (both mean "the previous syllable ended a line"),
`-` suffix = syllable joins the next one, `@`-prefixed tokens are
file metadata (`@KMIDI`, `@T<title>`, ...) and are dropped.
- **Plain Lyric-event convention**: word boundaries carried by leading
or trailing spaces; line breaks carried by embedded CR/LF.
Each token: {tick, word, lead_ws, trail_ws, line_end}. Spacing-only and
newline-only events don't emit a token — they fold their meaning
(word-break / line-end) onto the previous one.
"""
toks: list[dict] = []
for tick, raw in events:
text = "" if raw is None else str(raw)
if not text:
continue
if text.lstrip().startswith(("@", "%")):
# .kar metadata / sequencer directives, not sung text.
continue
kar_break = text[0] in ("/", "\\")
if kar_break:
text = text[1:]
m = _LYRIC_TOKEN_RE.match(text)
head, body, tail = m.group(1), m.group(2), m.group(3)
nl_before = ("\n" in head) or ("\r" in head)
nl_after = ("\n" in tail) or ("\r" in tail)
if "\n" in body or "\r" in body:
# Rare multi-line event: keep it one token, treat the break as
# trailing so the line ends after this token.
body = re.sub(r"[\r\n]+", " ", body).strip()
nl_after = True
if (kar_break or nl_before) and toks:
toks[-1]["line_end"] = True
if not body:
# Pure spacing/newline token: fold onto the previous syllable.
if nl_after and toks:
toks[-1]["line_end"] = True
if toks:
toks[-1]["trail_ws"] = True
continue
toks.append({
"tick": tick,
"word": body,
"lead_ws": bool(head),
"trail_ws": bool(tail),
"line_end": nl_after,
})
return toks
def _apply_word_conventions(toks: list[dict]) -> list[str]:
"""Map tokens to spec §7.1 `w` strings: trailing ``-`` joins to the next
syllable, trailing ``+`` ends a line.
Which join convention the source used is detected per stream:
- Any token already carrying a ``-`` suffix → the stream is
hyphen-delimited (`.kar` style); those suffixes are the spec's own
join marker and pass through untouched.
- Otherwise, if the stream carries any spacing at all → space-delimited:
a token with no trailing space followed by a token with no leading
space is a mid-word syllable and gains a ``-``.
- No hyphens and no spacing anywhere → the tokens are whole words
(common for Text-event lyrics); no joins are synthesized.
"""
has_hyphens = any(t["word"].endswith("-") for t in toks)
has_spacing = any(t["lead_ws"] or t["trail_ws"] for t in toks)
words: list[str] = []
for i, tk in enumerate(toks):
w = tk["word"]
nxt = toks[i + 1] if i + 1 < len(toks) else None
if tk["line_end"]:
# A join can't cross a line break — the line marker wins.
if w.endswith("-"):
w = w[:-1]
if w and not w.endswith("+"):
w += "+"
elif nxt is not None and not has_hyphens and has_spacing:
if not tk["trail_ws"] and not nxt["lead_ws"] and not w.endswith("-"):
w += "-"
words.append(w)
return words
def _select_vocal_notes(
scans: list[dict],
lyric_track_index: int,
midi_type: int,
) -> tuple[int, list[tuple[int, int, int, int]]] | None:
"""Pick the note pool the lyric syllables should be pitch-paired with.
Returns ``(track_index, notes)`` or ``None`` when no vocal melody is
identifiable (→ lyrics-only import). Selection order:
1. The lyric-carrying track itself, when it has notes:
- channels with a vocal GM program → only those channels' notes
(isolates the sung line inside a format-0 everything-in-one-track
file);
- vocal-ish track name → all its non-drum notes;
- SMF type 1/2 with neither → still trusted: a track that interleaves
per-syllable Lyric events with its own notes *is* the karaoke
melody by construction. Format-0 files don't get this benefit of
the doubt — there the single track holds every instrument, so
without a vocal program/name there is no way to isolate the melody
and we fall back to lyrics-only.
2. Otherwise (dedicated noteless "Words" track), the vocal-ish track —
by name hint or vocal GM program, mirroring gp2rs_gpx — with the
most notes; within it, vocal-program channels only when present.
"""
def _vocal_channels(scan: dict) -> set[int]:
return {
ch for ch, prog in scan["channel_programs"].items()
if prog in _VOCAL_MIDI_PROGRAMS
}
def _pool(scan: dict) -> list[tuple[int, int, int, int]]:
chans = _vocal_channels(scan)
if chans:
return [n for n in scan["notes"] if n[3] in chans]
return scan["notes"]
src = scans[lyric_track_index]
if src["notes"]:
if _vocal_channels(src) or _name_matches(src["name"], _VOCAL_NAME_HINTS):
return lyric_track_index, _pool(src)
if midi_type != 0:
return lyric_track_index, src["notes"]
return None
best: tuple[int, list] | None = None
for i, scan in enumerate(scans):
if not scan["notes"]:
continue
if not (_vocal_channels(scan)
or _name_matches(scan["name"], _VOCAL_NAME_HINTS)):
continue
pool = _pool(scan)
if pool and (best is None or len(pool) > len(best[1])):
best = (i, pool)
return best
def extract_midi_lyrics(midi_path: str, audio_offset: float = 0.0) -> dict | None:
"""Extract lyrics (and, when pairable, the vocal melody) from a `.mid`.
Returns ``None`` when the file carries no usable lyric events — callers
then change nothing, leaving any existing manifest keys and sidecar
files untouched. Otherwise returns::
{
"lyrics": [{"t": float, "d": float, "w": str}, ...],
"lyrics_source": "authored",
"vocal_pitch": {"version": 1,
"notes": [{"t", "d", "midi"}, ...]} | None,
}
``lyrics`` is the feedpak `lyrics.json` payload (spec §7.1: flat list,
no version field; ``w`` uses trailing ``-`` for syllable joins and
trailing ``+`` for line ends). ``vocal_pitch`` is the `vocal_pitch.json`
payload (spec §7.2, same shape as gp2rs_gpx's
``convert_vocal_track_to_pitch_sidecar`` and the lyrics-karaoke
plugin's ``_persist_pitch``) — ``None`` when no vocal note track could
be identified, in which case the caller writes `lyrics.json` only.
``lyrics_source`` is always ``"authored"`` (spec §7.1 vocabulary):
lyric meta events are chart-author data, not machine transcription.
Callers assembling a pack write ``lyrics.json`` /
``vocal_pitch.json`` and set the manifest ``lyrics`` /
``lyrics_source`` / ``vocal_pitch`` keys — and should do so only for
keys not already present, so an import never clobbers lyrics that
arrived from another source.
Sourcing rules:
- Lyric text comes from SMF Lyric (0x05) meta events — the track with
the most of them wins when several carry some. When the file has
none at all, Text (0x01) events are accepted as a fallback, but only
from a vocal-ish track (gp2rs_gpx-style name/program detection,
widened with "words"/"karaoke" for `.kar` text tracks) — Text events
elsewhere are copyright notices / markers, not lyrics.
- `.kar` conventions are normalized (see ``_normalize_lyric_tokens`` /
``_apply_word_conventions``): ``/`` and ``\\`` line-break prefixes
become the spec's ``+`` suffix on the previous syllable, ``@``
metadata tokens are dropped, ``-`` hyphen joins pass through.
- Each syllable is paired with the vocal note (see
``_select_vocal_notes``) whose onset falls within
``_LYRIC_PAIR_TOLERANCE_S`` of the lyric event, greedily in time
order, one note per syllable. Paired syllables snap ``t``/``d`` to
the note (the authored melody is timing-authoritative, and keeps
`lyrics.json` and `vocal_pitch.json` mirrored per §7.2); a melisma's
extra notes are skipped. Unpaired syllables (talkies) keep the lyric
event's own time and run until the next syllable, clamped to
[``_UNPAIRED_LYRIC_MIN_D``, ``_UNPAIRED_LYRIC_MAX_D``] — they appear
in ``lyrics`` only, which spec §7.2 explicitly allows
(`vocal_pitch.notes` MAY be shorter than `lyrics.json`).
``audio_offset`` (seconds) shifts every emitted time, same handle as
the keys/drums converters. Tempo-map scope per SMF type also matches
them (type 2 reads only the involved track's tempo events).
"""
offset = float(audio_offset)
if not math.isfinite(offset):
raise ValueError(f"audio_offset must be a finite number, got {audio_offset!r}")
midi = mido.MidiFile(midi_path)
midi_type = getattr(midi, "type", 1)
scans = _scan_tracks_for_lyrics(midi)
# ── choose the lyric event stream ────────────────────────────────────
lyric_idx = -1
best_count = 0
for i, scan in enumerate(scans):
if len(scan["lyric_events"]) > best_count:
lyric_idx = i
best_count = len(scan["lyric_events"])
if lyric_idx >= 0:
toks = _normalize_lyric_tokens(scans[lyric_idx]["lyric_events"])
else:
# Text-event fallback: vocal-ish tracks only (plus .kar "Words" /
# "Soft Karaoke" text tracks). Normalize before counting so a track
# of @-metadata can't outscore a real lyric track.
toks = []
for i, scan in enumerate(scans):
if not scan["text_events"]:
continue
vocal_prog = any(
p in _VOCAL_MIDI_PROGRAMS
for p in scan["channel_programs"].values()
)
if not (vocal_prog
or _name_matches(scan["name"], _LYRIC_TEXT_TRACK_HINTS)):
continue
cand = _normalize_lyric_tokens(scan["text_events"])
if len(cand) > len(toks):
lyric_idx = i
toks = cand
if lyric_idx < 0 or not toks:
return None
words = _apply_word_conventions(toks)
lyric_tick_to_seconds = _build_tick_to_seconds(midi, lyric_idx)
# ── pick + time the vocal note pool ──────────────────────────────────
picked = _select_vocal_notes(scans, lyric_idx, midi_type)
vocal_notes: list[dict] = []
if picked is not None:
note_idx, pool = picked
# Type-2 tracks own independent timelines — time the notes through
# their own track's tempo scope (same map as the lyric track for
# type 0/1, where tempo is merged across tracks anyway).
note_tick_to_seconds = (
lyric_tick_to_seconds if note_idx == lyric_idx
else _build_tick_to_seconds(midi, note_idx)
)
for start_tick, end_tick, pitch, _ch in pool:
t = note_tick_to_seconds(start_tick)
vocal_notes.append({
"t": t,
"d": max(0.0, note_tick_to_seconds(end_tick) - t),
"midi": int(pitch),
})
vocal_notes.sort(key=lambda n: n["t"])
# ── pair syllables with notes (greedy, time-ordered) ─────────────────
entries: list[dict] = [] # {t, d (None until resolved), w, paired}
j = 0
for tk, w in zip(toks, words):
t_lyric = lyric_tick_to_seconds(tk["tick"])
while (j < len(vocal_notes)
and vocal_notes[j]["t"] < t_lyric - _LYRIC_PAIR_TOLERANCE_S):
j += 1
if (j < len(vocal_notes)
and vocal_notes[j]["t"] <= t_lyric + _LYRIC_PAIR_TOLERANCE_S):
note = vocal_notes[j]
j += 1
entries.append({
"t": note["t"], "d": note["d"], "w": w,
"midi": note["midi"], "paired": True,
})
else:
entries.append({"t": t_lyric, "d": None, "w": w, "paired": False})
# Snapping can nudge a paired syllable past an unpaired neighbour;
# sort so both sidecars stay chronological for downstream consumers.
entries.sort(key=lambda e: e["t"])
# Unpaired durations: until the next syllable, clamped. Resolved after
# the sort so "next" is the true chronological neighbour.
for i, e in enumerate(entries):
if e["d"] is None:
if i + 1 < len(entries):
gap = entries[i + 1]["t"] - e["t"]
d = min(gap, _UNPAIRED_LYRIC_MAX_D)
else:
d = _UNPAIRED_LYRIC_MAX_D
e["d"] = max(d, _UNPAIRED_LYRIC_MIN_D)
lyrics_out = [
{"t": round(e["t"] + offset, 3), "d": round(e["d"], 3), "w": e["w"]}
for e in entries
]
pitch_notes = [
{"t": round(e["t"] + offset, 3), "d": round(e["d"], 3),
"midi": int(e["midi"])}
for e in entries if e["paired"]
]
return {
"lyrics": lyrics_out,
"lyrics_source": "authored",
"vocal_pitch": (
{"version": 1, "notes": pitch_notes} if pitch_notes else None
),
}
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@@ -0,0 +1,282 @@
"""Tests for lib/midi_import.py — extract_midi_lyrics (lyrics + vocal melody).
Synthetic mido.MidiFile objects are built in-memory and saved to tmp_path,
same style as test_midi_import.py.
Covers:
- Lyric (0x05) events on a vocal track → lyrics.json + vocal_pitch.json payloads
- lyric/note pairing snaps t/d to the note; midi pitch carried through
- lyrics with no identifiable vocal track → lyrics payload only
- no lyric events at all → None (import behavior unchanged)
- .kar '/' line-break prefixes → spec trailing '+' on the previous syllable
- .kar '-' hyphen joins pass through untouched
- space-delimited syllable streams gain '-' joins
- '@'-metadata tokens dropped; Text-event (0x01) fallback on vocal-ish tracks
- Text events on non-vocal tracks are NOT treated as lyrics
- unpaired lyric durations run to the next syllable, capped at 2.0 s
- format-0 mixed-channel file pairs only the vocal-program channel
- vocal GM program (52-54 / 85-87) detection without a track name
- audio_offset applied to both payloads
"""
import pytest
import mido
from midi_import import extract_midi_lyrics
TPB = 480 # ticks per beat; default 120 BPM → 480 ticks = 0.5 s
def _save(mid: mido.MidiFile, tmp_path, name: str = "test.mid") -> str:
p = tmp_path / name
mid.save(str(p))
return str(p)
def _vocal_file(tmp_path, *, track_name="Vocals", program=None, meta="lyrics",
syllables=("Hel-", "lo", "world")):
"""Type-1 file: conductor + one melody track carrying notes with a lyric
event at each note-on. Notes: 60, 62, 64, each one beat (0.5 s) long,
back to back."""
mid = mido.MidiFile(type=1, ticks_per_beat=TPB)
conductor = mido.MidiTrack()
mid.tracks.append(conductor)
conductor.append(mido.MetaMessage("set_tempo", tempo=500000, time=0))
tr = mido.MidiTrack()
mid.tracks.append(tr)
if track_name:
tr.append(mido.MetaMessage("track_name", name=track_name, time=0))
if program is not None:
tr.append(mido.Message("program_change", channel=0, program=program, time=0))
for i, syl in enumerate(syllables):
tr.append(mido.MetaMessage(meta, text=syl, time=0))
tr.append(mido.Message("note_on", channel=0, note=60 + 2 * i,
velocity=90, time=0))
tr.append(mido.Message("note_off", channel=0, note=60 + 2 * i,
velocity=0, time=TPB))
return _save(mid, tmp_path)
# ── both sidecars from a lyric+vocal-track file ──────────────────────────────
def test_vocal_track_emits_both_payloads(tmp_path):
result = extract_midi_lyrics(_vocal_file(tmp_path))
assert result is not None
assert result["lyrics_source"] == "authored"
lyr = result["lyrics"]
assert [e["w"] for e in lyr] == ["Hel-", "lo", "world"]
assert [e["t"] for e in lyr] == pytest.approx([0.0, 0.5, 1.0])
# Paired syllables snap d to the note duration (1 beat = 0.5 s).
assert [e["d"] for e in lyr] == pytest.approx([0.5, 0.5, 0.5])
vp = result["vocal_pitch"]
assert vp is not None
assert vp["version"] == 1
assert [n["midi"] for n in vp["notes"]] == [60, 62, 64]
# vocal_pitch t/d mirror the matching lyrics entries (spec §7.2).
assert [(n["t"], n["d"]) for n in vp["notes"]] == \
[(e["t"], e["d"]) for e in lyr]
def test_vocal_program_detection_without_name(tmp_path):
"""GM program 53 (Voice Oohs) marks the track vocal even with no name."""
path = _vocal_file(tmp_path, track_name="", program=53)
result = extract_midi_lyrics(path)
assert result is not None
assert result["vocal_pitch"] is not None
assert [n["midi"] for n in result["vocal_pitch"]["notes"]] == [60, 62, 64]
# ── lyrics-only fallbacks ────────────────────────────────────────────────────
def test_no_vocal_track_emits_lyrics_only(tmp_path):
"""Lyric events on a noteless track + only a piano note track → the
lyrics payload is emitted but vocal_pitch is None (talkies path)."""
mid = mido.MidiFile(type=1, ticks_per_beat=TPB)
conductor = mido.MidiTrack()
mid.tracks.append(conductor)
conductor.append(mido.MetaMessage("set_tempo", tempo=500000, time=0))
words = mido.MidiTrack()
mid.tracks.append(words)
words.append(mido.MetaMessage("lyrics", text="Hello ", time=0))
words.append(mido.MetaMessage("lyrics", text="there ", time=TPB))
piano = mido.MidiTrack()
mid.tracks.append(piano)
piano.append(mido.MetaMessage("track_name", name="Piano", time=0))
piano.append(mido.Message("program_change", channel=0, program=0, time=0))
piano.append(mido.Message("note_on", channel=0, note=48, velocity=90, time=0))
piano.append(mido.Message("note_off", channel=0, note=48, velocity=0, time=TPB))
result = extract_midi_lyrics(_save(mid, tmp_path))
assert result is not None
assert [e["w"] for e in result["lyrics"]] == ["Hello", "there"]
assert result["vocal_pitch"] is None
def test_no_lyrics_returns_none(tmp_path):
"""A file without lyric events changes nothing — extraction reports None."""
mid = mido.MidiFile(type=0, ticks_per_beat=TPB)
tr = mido.MidiTrack()
mid.tracks.append(tr)
tr.append(mido.Message("note_on", channel=0, note=60, velocity=90, time=0))
tr.append(mido.Message("note_off", channel=0, note=60, velocity=0, time=TPB))
assert extract_midi_lyrics(_save(mid, tmp_path)) is None
def test_unpaired_duration_next_event_capped_at_2s(tmp_path):
"""Unpaired lyric entries last until the next syllable, capped at 2.0 s."""
mid = mido.MidiFile(type=1, ticks_per_beat=TPB)
conductor = mido.MidiTrack()
mid.tracks.append(conductor)
conductor.append(mido.MetaMessage("set_tempo", tempo=500000, time=0))
words = mido.MidiTrack()
mid.tracks.append(words)
words.append(mido.MetaMessage("lyrics", text="one ", time=0))
words.append(mido.MetaMessage("lyrics", text="two ", time=TPB)) # +0.5 s
words.append(mido.MetaMessage("lyrics", text="three ", time=TPB * 8)) # +4.0 s
result = extract_midi_lyrics(_save(mid, tmp_path))
lyr = result["lyrics"]
assert lyr[0]["d"] == pytest.approx(0.5) # gap to next syllable
assert lyr[1]["d"] == pytest.approx(2.0) # 4.0 s gap capped
assert lyr[2]["d"] == pytest.approx(2.0) # last entry: cap value
# ── .kar conventions ─────────────────────────────────────────────────────────
def test_kar_slash_line_break_maps_to_plus(tmp_path):
"""A '/' prefix on a syllable marks the END of the previous line — the
previous syllable gains the spec's trailing '+'."""
path = _vocal_file(
tmp_path, syllables=("Hel-", "lo", "/world"))
result = extract_midi_lyrics(path)
words = [e["w"] for e in result["lyrics"]]
assert words == ["Hel-", "lo+", "world"]
def test_kar_backslash_paragraph_break_maps_to_plus(tmp_path):
path = _vocal_file(tmp_path, syllables=("one", "\\two", "three"))
words = [e["w"] for e in extract_midi_lyrics(path)["lyrics"]]
assert words == ["one+", "two", "three"]
def test_kar_hyphen_joins_pass_through(tmp_path):
""".kar hyphen suffixes already ARE the spec join marker — untouched,
and no extra '-' is synthesized onto hyphenless word-final syllables."""
path = _vocal_file(tmp_path, syllables=("beau-", "ti-", "ful", "day"))
words = [e["w"] for e in extract_midi_lyrics(path)["lyrics"]]
assert words == ["beau-", "ti-", "ful", "day"]
def test_space_delimited_stream_gains_hyphen_joins(tmp_path):
"""Space-delimited Lyric streams ('Hel' 'lo ' 'world') carry word
boundaries in whitespace — mid-word syllables gain the '-' join."""
path = _vocal_file(tmp_path, syllables=("Hel", "lo ", "world "))
words = [e["w"] for e in extract_midi_lyrics(path)["lyrics"]]
assert words == ["Hel-", "lo", "world"]
def test_newline_in_lyric_event_ends_line(tmp_path):
path = _vocal_file(tmp_path, syllables=("one \n", "two ", "three "))
words = [e["w"] for e in extract_midi_lyrics(path)["lyrics"]]
assert words == ["one+", "two", "three"]
# ── Text-event (0x01) fallback ───────────────────────────────────────────────
def test_text_event_fallback_on_vocal_track(tmp_path):
"""With no 0x05 events anywhere, Text events on a vocal-ish track are
accepted as lyrics; '@'-prefixed .kar metadata tokens are dropped."""
mid = mido.MidiFile(type=1, ticks_per_beat=TPB)
conductor = mido.MidiTrack()
mid.tracks.append(conductor)
conductor.append(mido.MetaMessage("set_tempo", tempo=500000, time=0))
tr = mido.MidiTrack()
mid.tracks.append(tr)
tr.append(mido.MetaMessage("track_name", name="Melody", time=0))
tr.append(mido.MetaMessage("text", text="@KMIDI KARAOKE FILE", time=0))
tr.append(mido.MetaMessage("text", text="@T A Song", time=0))
for i, syl in enumerate(("Some ", "words ")):
tr.append(mido.MetaMessage("text", text=syl, time=0))
tr.append(mido.Message("note_on", channel=0, note=64 + i, velocity=90,
time=0))
tr.append(mido.Message("note_off", channel=0, note=64 + i, velocity=0,
time=TPB))
result = extract_midi_lyrics(_save(mid, tmp_path))
assert result is not None
assert [e["w"] for e in result["lyrics"]] == ["Some", "words"]
assert [n["midi"] for n in result["vocal_pitch"]["notes"]] == [64, 65]
def test_text_events_on_non_vocal_track_ignored(tmp_path):
"""Text events on a plain instrument track (copyright notices, markers)
are not lyrics — extraction returns None."""
mid = mido.MidiFile(type=1, ticks_per_beat=TPB)
conductor = mido.MidiTrack()
mid.tracks.append(conductor)
conductor.append(mido.MetaMessage("set_tempo", tempo=500000, time=0))
tr = mido.MidiTrack()
mid.tracks.append(tr)
tr.append(mido.MetaMessage("track_name", name="Guitar", time=0))
tr.append(mido.MetaMessage("text", text="Copyright 2026", time=0))
tr.append(mido.Message("note_on", channel=0, note=52, velocity=90, time=0))
tr.append(mido.Message("note_off", channel=0, note=52, velocity=0, time=TPB))
assert extract_midi_lyrics(_save(mid, tmp_path)) is None
# ── format-0 channel isolation ───────────────────────────────────────────────
def test_format0_pairs_only_vocal_program_channel(tmp_path):
"""Format-0 file mixing a vocal-program channel with an accompaniment
channel: only the vocal channel's notes feed vocal_pitch."""
mid = mido.MidiFile(type=0, ticks_per_beat=TPB)
tr = mido.MidiTrack()
mid.tracks.append(tr)
tr.append(mido.Message("program_change", channel=0, program=53, time=0)) # Voice Oohs
tr.append(mido.Message("program_change", channel=1, program=0, time=0)) # Piano
# Simultaneous piano note that must NOT be paired.
tr.append(mido.Message("note_on", channel=1, note=40, velocity=90, time=0))
tr.append(mido.MetaMessage("lyrics", text="la ", time=0))
tr.append(mido.Message("note_on", channel=0, note=67, velocity=90, time=0))
tr.append(mido.Message("note_off", channel=0, note=67, velocity=0, time=TPB))
tr.append(mido.Message("note_off", channel=1, note=40, velocity=0, time=0))
result = extract_midi_lyrics(_save(mid, tmp_path))
assert result is not None
assert [n["midi"] for n in result["vocal_pitch"]["notes"]] == [67]
def test_format0_without_vocal_channel_is_lyrics_only(tmp_path):
"""Format-0 with lyrics but no vocal program/name: the merged note soup
cannot be trusted as a melody — lyrics.json only."""
mid = mido.MidiFile(type=0, ticks_per_beat=TPB)
tr = mido.MidiTrack()
mid.tracks.append(tr)
tr.append(mido.Message("program_change", channel=0, program=0, time=0))
tr.append(mido.MetaMessage("lyrics", text="la ", time=0))
tr.append(mido.Message("note_on", channel=0, note=60, velocity=90, time=0))
tr.append(mido.Message("note_off", channel=0, note=60, velocity=0, time=TPB))
result = extract_midi_lyrics(_save(mid, tmp_path))
assert result is not None
assert len(result["lyrics"]) == 1
assert result["vocal_pitch"] is None
# ── audio_offset ─────────────────────────────────────────────────────────────
def test_audio_offset_applied_to_both_payloads(tmp_path):
result = extract_midi_lyrics(_vocal_file(tmp_path), audio_offset=1.5)
assert result["lyrics"][0]["t"] == pytest.approx(1.5)
assert result["vocal_pitch"]["notes"][0]["t"] == pytest.approx(1.5)