Files
VoiceStudio/docs/engines/sherpa-onnx.md
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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

2.5 KiB

VoiceStudio — Sherpa-ONNX Engine

Sherpa-ONNX (k2-fsa/sherpa-onnx) is a unified C++ ONNX runtime that wraps 20+ TTS model families (VITS, MeloTTS, Piper, Kokoro, Matcha, and more) behind one API, with pre-built wheels for Linux, Windows, and macOS (x86 and ARM). You bring the model: point VoiceStudio at any downloaded sherpa-onnx TTS model directory.

When to pick it

  • You want a specific community model (e.g. a Piper or VITS voice for your language) that no other engine hosts.
  • You need a dependable CPU engine with optional CUDA acceleration.

Setup

  1. Install the runtime:

    pip install sherpa-onnx
    
  2. Download a TTS model from the sherpa-onnx releases and unpack it somewhere permanent.

  3. Point VoiceStudio at the model directory and restart:

    export OMNIVOICE_SHERPA_MODEL=/path/to/model-dir
    
  4. Select the engine via Model Catalogue → Engines or OMNIVOICE_TTS_BACKEND=sherpa-onnx.

The directory must contain model.onnx and tokens.txt. Sherpa-ONNX ships no bundled default model, so the engine reports unavailable — with the reason — until OMNIVOICE_SHERPA_MODEL points at a valid directory. (Before this gate, selecting the engine unconfigured produced a failure mislabeled as out-of-memory — #919.)

Configuration

Variable Default Meaning
OMNIVOICE_SHERPA_MODEL (unset) Directory containing model.onnx + tokens.txt

Behaviour notes

  • Output defaults to 22.05 kHz (the VITS default); once a model is loaded, its own sample rate is used.
  • CPU is the universal baseline; the CUDA onnxruntime provider is available on Linux/Windows installs.
  • No cloning: voices come from the model itself. Multi-speaker VITS models select a voice by numeric speaker id; speed is supported.
  • Languages depend entirely on the model you download.

Known limits

  • One model at a time — switching models means changing OMNIVOICE_SHERPA_MODEL and restarting.
  • No voice design, no reference-audio cloning, no emotion controls (see expressive-speech.md).

Troubleshooting

  • "OMNIVOICE_SHERPA_MODEL not set" / "No model.onnx in …": follow Setup above — the variable must point at the unpacked model directory, not the archive.
  • Other issues: install/troubleshooting.md.

See also: benchmarks.md, languages.md, disk usage.