Files
VoiceStudio/docs/engines/kittentts.md
T
Palash DebnathandClaude Fable 5 030d5ea01f docs(engines): a guide for every engine + index; fix two engine-metadata bugs (#1556)
* docs(engines): a guide for every engine + index; fix two engine-metadata bugs

21 new pages under docs/engines/ (10 TTS, 10 ASR, index README) — every
registered engine now has one: what it's for, platform support, model env
vars, quirks with issue refs. Linked from both READMEs' engine sections.

Code fixes found while verifying facts against the registries:
- KittenTTS docstring claimed default voice 'Jasper'; the code default is
  expr-voice-2-f
- the isolated-ASR sidecar read only ASR_MODEL_FW while the download
  preflight read ASR_MODEL_FASTER — set one and the other quietly used a
  different model; both now resolve ASR_MODEL_FW-override → ASR_MODEL_FASTER
- moonshine's install hint named 'useful-moonshine', a package the backend
  never imports; now moonshine-onnx / moonshine-voice

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

* docs(changelog): entries for the engine guides + sidecar model fix (#1556)

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

* docs(engines): second-harvest fixes — TLS guidance, matrix/code alignment, CN counts

- README matrix aligned to gpu_compat (the code is the source of truth):
  CosyVoice macOS is CPU not MPS, IndexTTS and GGUF gain their real
  CUDA/CPU/MPS cells
- gpt-sovits guide: prefer https/tunnel for non-loopback servers, plaintext
  warning; first-use download guidance on both OmniVoice pages
- preflight empty-env fallback matches the sidecar (ASR_MODEL_FASTER='' no
  longer resolves a different repo)
- nano installs via uv pip; kitten log level wording; index links install
  guides incl. the Gatekeeper step; README_CN engine counts 16/11

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

* docs(readme-cn): the all-engines-local claim now excludes the remote client

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

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-08-15 03:55:59 +00:00

2.4 KiB
Raw Blame History

VoiceStudio — KittenTTS Engine

KittenTTS (KittenML) is the lightweight English "flash" tier: a 2580 MB ONNX model with 8 preset voices that runs realtime on any CPU — no torch, no CUDA, no GPU of any kind. Use it when you just need quick English narration (voiceovers, demo reads, short phrases) with no reference sample.

When to pick it

  • English-only content where speed and a tiny install matter more than cloning.
  • Machines with no usable GPU.

The trade-off against OmniVoice: no voice cloning, English only — but a much faster and much smaller install.

Setup

pip install kittentts

Then select the engine via Model Catalogue → Engines or OMNIVOICE_TTS_BACKEND=kittentts.

Voices

Eight preset voices, four male/female pairs:

expr-voice-2-m  expr-voice-2-f   (default: expr-voice-2-f)
expr-voice-3-m  expr-voice-3-f
expr-voice-4-m  expr-voice-4-f
expr-voice-5-m  expr-voice-5-f

An unknown voice id logs an info message and falls back to the default.

Model selection

Variable Default Meaning
OMNIVOICE_KITTENTTS_MODEL KittenML/kitten-tts-mini-0.8 HuggingFace checkpoint to load

The ~80 MB model downloads from HuggingFace on first use (retried once on a flaky connection). See downloading-models.md.

Behaviour notes

  • Output is 24 kHz mono.
  • CPU-only by design — the ONNX graph has no CUDA/MPS path.
  • Non-English language values are ignored with a log line pointing at OmniVoice; reference audio is likewise ignored (no cloning).
  • Long-input hardening (#1173): the shipped ONNX graph has a hard 512-token cap, and phonemization can expand text massively (digits especially). VoiceStudio pre-measures every chunk with the model's own tokenizer and splits oversized chunks at word boundaries, so long or digit-heavy inputs no longer abort inside onnxruntime with an opaque "invalid expand shape" error.

Known limits

  • English only; no cloning, no voice design, no emotion controls (see expressive-speech.md).
  • Preset voices only — speed is the one knob.

Troubleshooting

  • Engine unavailable: pip install kittentts into VoiceStudio's Python environment and restart.
  • Other issues: install/troubleshooting.md.

See also: benchmarks.md, disk usage.