mir-transcription

name	mir-transcription
description	Lead-vocal MIR transcription guidance for SunoScribe. Use when designing, reviewing, or modifying media ingest, vocal separation, RMVPE/F0 extraction, voiced/unvoiced handling, note segmentation, beat/downbeat analysis, quantization, ScoreIR transcription, MIDI export, MusicXML export, or any audio/video-to-score pipeline behavior.

MIR Transcription

Use this skill to keep SunoScribe transcription work aligned with the MIR principles distilled from doc/principles/mirdoc.md.

Core Rule

Preserve the representation chain:

MediaAsset -> CanonicalAudio -> StemSet -> F0Track -> NoteCandidateSet -> RhythmGrid -> ScoreRevision -> Artifacts

Do not collapse the chain into audio -> MIDI or audio -> MusicXML. Each stage must consume typed input and produce typed output.

Required Workflow

1. Identify the representation being changed.

   • Audio waveforms preserve sound but not note labels.
   • F0 tracks preserve pitch evidence but not score rhythm.
   • MIDI preserves events but not score notation semantics.
   • MusicXML preserves notation semantics but is not the analysis source of truth.

2. Keep vocal melody transcription separate from harmony analysis.

   • Use vocals for lead F0.
   • Use accompaniment/mix later for chord, chroma, structure, or rhythm support.
   • Do not use chroma as note transcription; chroma folds octaves.

3. Treat RMVPE/F0 output as evidence, not final notes.

   • Preserve continuous F0, voiced/unvoiced state, confidence, and timestamps.
   • Detect likely octave errors before quantization.
   • Keep slides and vibrato visible in debug artifacts.

4. Build rhythm independently.

   • Beat/downbeat analysis must produce a RhythmGrid.
   • Quantization must consume NoteCandidateSet + RhythmGrid.
   • Low downbeat confidence should surface as a warning or issue, not hidden correction.

5. Generate score from ScoreIR or ScoreRevision.

   • MIDI and MusicXML must derive from the same semantic revision.
   • Do not let export code invent musical decisions that are absent from ScoreIR.

Production Constraints

• Required production stages fail explicitly.
• Missing RMVPE runtime/model is not a successful transcription.
• Vocal separation failure is not a successful lead-vocal MVP.
• Debug artifact failures may warn, but required musical artifacts must not be faked.
• Baseline harmony, structure, or bass guesses must not pollute the lead-vocal MVP.

Debug Artifacts To Preserve

For meaningful diagnosis, prefer generating or consuming:

• waveform
• spectrogram
• vocals/accompaniment previews
• F0 trajectory with voiced/unvoiced regions
• note candidate timeline
• beat/downbeat grid
• quantized note overlay
• MIDI/MusicXML export metadata

Review Checklist

Before accepting a transcription change, confirm:

• The input and output representations are explicit.
• F0 evidence remains available after note segmentation.
• Rhythm grid is independent and inspectable.
• Quantization errors can be traced to F0, beat, downbeat, or note segmentation.
• Exports are generated from ScoreIR, not ad hoc from unrelated intermediate data.