# Gtsinger Eval

> Evaluates singing voice synthesis models on technique-controllable generation, singer similarity, and audio quality across multiple languages and vocal techniques. It probes the model's ability to accurately control specific singing techniques (e.g., vibrato, mixed voice) while maintaining naturalness and timbre fidelity. Use when the user wants to benchmark on GTSinger, or asks about evaluating this task. Reports MOS-Q.

- Skill: `qhjqhj00/gtsinger-eval` (Agent Skill)
- Install (CLI): `npx skillmds add qhjqhj00/gtsinger-eval`
- Raw SKILL.md: https://api.skillmd.com/api/skills/qhjqhj00/gtsinger-eval/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: qhjqhj00 (https://skillmd.com/u/qhjqhj00)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/qhjqhj00/gtsinger-eval

---


# gtsinger-eval

> GTSinger: A Global Multi-Technique Singing Corpus with Realistic Music Scores for All Singing Tasks — Yu Zhang et al. (2024) (arXiv:2409.13832, 2024)

## What this evaluates

Evaluates singing voice synthesis models on technique-controllable generation, singer similarity, and audio quality across multiple languages and vocal techniques. It probes the model's ability to accurately control specific singing techniques (e.g., vibrato, mixed voice) while maintaining naturalness and timbre fidelity.

## Datasets

- **GTSinger** — total ?; splits: test (-1); repo https://github.com/AaronZ345/GTSinger

## Metrics

- `MOS-Q` **(primary)** — range: other
  - Average Likert scale score (1-5) assigned by professional listeners evaluating synthesis quality (clarity, naturalness, and rich stylistic details).
- `MOS-S` — range: other
  - Average Likert scale score (1-5) assigned by professional listeners evaluating singer similarity (timbre and style match to reference audio).
- `MOS-C` — range: other
  - Average Likert scale score (1-5) assigned by professional listeners evaluating technique controllability (accuracy and expressiveness of technique control).
- `FFE` — range: other
  - F0 Frame Error combining voicing decision error and F0 error to comprehensively capture pitch and voicing information.
- `MCD` — range: other
  - Mean Cepstral Distortion: (10/ln10) * sqrt(2 * sum_{d=1}^D (c_t(d) - c_hat_t(d))^2), measuring spectral distortion between target and predicted MFCCs.
- `Cos` — range: [-1, 1]
  - Cosine similarity between WavLM speaker verification embeddings extracted from synthesized and ground truth audio.

## Input / output format

**Input**: Synthesized singing audio and reference (ground truth) audio; for technique control, binary sequences indicating technique presence per phoneme.

**Output**: Subjective: Likert scores 1-5 per listener. Objective: FFE, MCD, and Cosine Similarity values.

## Scoring recipe

```python
def compute_metrics(predictions, gold, listeners):
    # Subjective MOS-Q/S/C
    scores = [listener.rating for listener in listeners]  # 1-5
    mos = sum(scores) / len(scores)
    
    # Objective: MCD
    mcd = (10 / ln(10)) * sqrt(2 * sum((c_t[d] - c_hat_t[d])**2 for d in range(D)))
    
    # Objective: FFE
    ffe = voicing_error_rate + f0_error_rate  # Combined metric
    
    # Objective: Cosine Similarity
    cos_sim = cosine_similarity(wavlm_embed(predictions), wavlm_embed(gold))
    
    return {'mos': mos, 'mcd': mcd, 'ffe': ffe, 'cos': cos_sim}
```

## Common pitfalls

- Listeners may conflate synthesis quality with singer similarity or technique controllability if instructions are not strictly enforced.
- FFE combines voicing and pitch errors, which can obscure whether performance issues stem from pitch accuracy or voicing detection.
- Subjective evaluation relies on a small test subset (50 sentences) and requires professional listeners, limiting reproducibility and scalability.

## Evidence (verbatim from paper)

> For each task, we randomly select 50 sentences from our test set for subjective evaluation... we conduct the MOS (Mean opinion score) evaluation... listeners are instructed to concentrate on synthesis quality... MOS-S evaluations, the listeners are directed to assess singer similarity... MOS-C, the listeners are informed to evaluate technique controllability... grade various singing voice samples on a Likert scale ranging from 1 to 5. ... we use F0 Frame Error (FFE)... employ Mean Cepstral Distortion (MCD) for measuring audio quality as the formula: MCD = (10/ln10) sqrt(2 sum (c_t(d) - c_hat_t(d))^2)... Cosine Similarity (Cos) is utilized to quantify the resemblance between the synthesized and reference singing voices.

## Citation

```bibtex
@misc{zhang2024gtsinger,
  title={GTSinger: A Global Multi-Technique Singing Corpus with Realistic Music Scores for All Singing Tasks},
  author={Yu Zhang et al. (2024)},
  year={2024},
  note={arXiv:2409.13832}
}
```

- arXiv: 2409.13832