Goal
This page explains Score and Note details for song synthesis.
The behavior is based on Revolution\Voicevox\Song\Note, Score, and SongAudioQuery.
Note class
Note represents one musical note (or one rest).
use Revolution\Voicevox\Song\Note;
$note = Note::make(
length: 94,
lyric: 'ド',
key: 60,
id: 'intro-1',
);
Constructor arguments
| Argument | Type | Description |
|---|
length | int | Frame length. Integer value based on seconds × 93.75 |
lyric | string | Lyrics text. Use '' for rests |
key | int|null | MIDI note number. Use null for rests |
id | string|null | Optional ID copied to note_id in FrameAudioQuery generation |
Frame-length calculation
length is in frames. From seconds:
This is not very intuitive, so Note::len() is the practical helper for MIDI-oriented workflows.
Note::len(int $ticks, int $bpm = 125): int
- Uses the common MIDI assumption: quarter note =
480 ticks
- Default tempo is
125 BPM
- Internally rounds to integer with
round(), so long songs can accumulate small rounding errors
Note::make(length: Note::len(480, 120), lyric: 'ド', key: 60); // quarter note
Note::make(length: Note::len(960, 120), lyric: 'ミ', key: 64); // half note
Note::len() is convenient, but keep cumulative rounding error in mind for long compositions.
Rest representation
A rest is expressed as:
Note::make(length: 15, lyric: '', key: null);
MIDI note quick table
| Note | MIDI |
|---|
| C4 | 60 |
| D4 | 62 |
| E4 | 64 |
| F4 | 65 |
| G4 | 67 |
| A4 | 69 |
| B4 | 71 |
| C5 | 72 |
Score class
Score is a container for an array of Note objects.
use Revolution\Voicevox\Song\Score;
$score = Score::make([
Note::make(length: 15, lyric: '', key: null),
Note::make(length: Note::len(480, 120), lyric: 'ド', key: 60),
]);
Critical rule
The first note must always be a rest.
Main API
Score::make(array $notes) to create a scoreadd(Note $note) to append one notetoJson() to serialize
$score = Score::make([
Note::make(length: 15, lyric: '', key: null),
]);
$score->add(Note::make(length: Note::len(480, 120), lyric: 'ド', key: 60));
$json = $score->toJson(JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
Score internally normalizes array input and handles empty-string/null lyric cases, so it stays safe with Laravel’s ConvertEmptyStringsToNull middleware in form-driven flows.
Practical pattern: Manage chart data in JSON (recommended)
In production, storing chart data in JSON is usually more maintainable than hardcoding long note arrays in PHP.
- Save your own chart format as JSON
- Load JSON and convert into
Note / Score
- Pass it to
Voicevox::song() for synthesis
JSON example
{
"teacher": 6000,
"speaker": 3001,
"bpm": 120,
"notes": [
{ "ticks": 120, "lyric": "", "key": null, "id": "r0" },
{ "ticks": 480, "lyric": "ド", "key": 60, "id": "n1" },
{ "ticks": 480, "lyric": "レ", "key": 62, "id": "n2" },
{ "ticks": 960, "lyric": "ミ", "key": 64, "id": "n3" },
{ "ticks": 120, "lyric": "", "key": null, "id": "r1" }
]
}
Load and synthesize
use Illuminate\Support\Facades\Storage;
use Revolution\Voicevox\Song\Note;
use Revolution\Voicevox\Song\Score;
use Revolution\Voicevox\Voicevox;
$chart = json_decode(
Storage::disk('local')->get('songs/sample.json'),
true,
flags: JSON_THROW_ON_ERROR,
);
$score = Score::make(
collect($chart['notes'])
->map(fn (array $note) => Note::make(
length: Note::len(ticks: $note['ticks'], bpm: $chart['bpm']),
lyric: $note['lyric'] ?? '',
key: $note['key'],
id: $note['id'] ?? null,
))
->all(),
);
$response = Voicevox::song($score, teacher: $chart['teacher'])
->generate(id: $chart['speaker']);
$response->storeAs('songs', 'sample.wav');
Related pages
