Status: validated end-to-end (2026-07-02). The integration (engine registration, dedicated-venv bootstrap, sidecar wire protocol, opt-in gating) is done, the sidecar's pure logic is unit-tested (
tests/test_confucius4_sidecar.py), and a live synthesis run on Apple Silicon (CPU) produced audible cloned speech — confirming the model API and the true output sample rate of 22 050 Hz. CUDA is the recommended hardware; CPU works but is slow (~17× realtime — roughly 100 s for 6 s of audio). MPS also runs but is slower than CPU (~64× realtime), so the sidecar deliberately never selects it. The engine is gated behindOMNIVOICE_CONFUCIUS4_TTS_DIR, so it's completely inert until you opt in — it can't affect the default install on any platform.
Confucius4-TTS (netease-youdao) is an LLM-based multilingual / cross-lingual zero-shot voice-cloning TTS.
- 14 languages: Chinese, English, Japanese, Korean, German, French, Spanish, Indonesian, Italian, Thai, Portuguese, Russian, Malay, Vietnamese.
- Unconstrained cloning — no reference transcript required.
- Cross-lingual voice transfer — keep one voice across languages.
- License: Apache-2.0. Hardware: NVIDIA GPU (CUDA 12.6) recommended; CPU validated on Apple Silicon but ~17× realtime. Output: 22 050 Hz mono.
Like IndexTTS-2 / MOSS-TTS-v1.5 / dots.tts, it runs in its own subprocess venv so its dependency stack never touches the default VoiceStudio interpreter.
git clone https://github.com/netease-youdao/Confucius4-TTS.git
cd Confucius4-TTS
uv venv --python 3.10
uv pip install -r requirements.txtUpstream ships no
pyproject.toml/setup.py, so there is nothing topip install -e— don't try; it fails. The VoiceStudio sidecar puts the clone onsys.pathitself (the same thing upstream'sexample.pydoes).
Model weights — all fetched automatically from HuggingFace on first
synthesis (~5 GB total, cached in $HF_HUB_CACHE):
netease-youdao/Confucius4-TTS—t2s_model.safetensors+s2a_model.pt(the tokenizer +wav2vec2bert_stats.ptalready ship in the clone'scheckpoints/).facebook/w2v-bert-2.0— semantic feature extractor (~2.3 GB).funasr/campplus— speaker-style encoder (small).nvidia/bigvgan_v2_22khz_80band_256x— vocoder (BigVGAN and CAMPPlus code is vendored in the clone'sexternal/; no Amphion install needed).
Set your HF_TOKEN (Settings → Credentials) if you hit rate limits.
Then point VoiceStudio at the clone and restart:
- macOS/Linux:
export OMNIVOICE_CONFUCIUS4_TTS_DIR=/path/to/Confucius4-TTS - Windows (PowerShell):
[Environment]::SetEnvironmentVariable("OMNIVOICE_CONFUCIUS4_TTS_DIR","C:\path\to\Confucius4-TTS","User")
Select Confucius4-TTS in Model Catalogue → Engines. The first synthesize triggers the weight downloads above, then generates.
OMNIVOICE_CONFUCIUS4_CONFIG— path toinference_config.yamlif it isn't at<clone>/config/inference_config.yaml.
The sidecar (backend/engines/confucius4/main.py) uses:
from confuciustts.cli.inference import ConfuciusTTS
model = ConfuciusTTS(config_path=..., device="cuda") # or "cpu"
audio = model.generate(text=..., lang="en", prompt_wav="ref.wav") # → tensor
sr = model.sample_rate # 22050- ✅ Live end-to-end run: English zero-shot clone from a 9.5 s reference —
6.06 s of audible speech (peak 0.85) in 102 s on CPU.
model.sample_ratereturned 22 050, matchingtarget_sample_rateinconfig/inference_config.yaml;CONFUCIUS_SAMPLE_RATE/_DEFAULT_SAMPLE_RATEare pinned to it (regression-tested). - ✅ Not pip-installable upstream — discovered live; the bootstrap now skips
the editable install unless upstream ships packaging, and both the import
probe and the sidecar resolve
confuciusttsvia the clone onsys.path. - ✅ MPS probed and rejected: runs, but ~4× slower than CPU (Metal op fallbacks) — the sidecar selects CUDA when available, else CPU, never MPS.
- ✅ Sidecar logic unit-tested (
tests/test_confucius4_sidecar.py): language normalization, tensor→PCM (mono/stereo/clip), config-path resolution, clone sys.path injection, wire framing, synthesize dispatch.
The sidecar passes a runtime-available CUDA/ROCm, XPU, or registered NPU through upstream's device-aware model loading. The engine venv needs a matching PyTorch/vendor runtime, also noted in the catalogue install hint. XPU/NPU selection is covered by mocked loader and routing tests; this change does not certify synthesis on physical XPU/NPU hardware. MPS keeps the existing CPU fallback described in the validation record above. If modern accelerator detection or the legacy CUDA probe raises, loading falls back to CPU instead of aborting before model construction.