feat: add Soprano TTS as community model with GGUF packages

[drzsdrtfg]

Soprano TTS — Community Model

Soprano is an ultra-lightweight (~80M parameter) English-only text-to-speech model using a two-stage architecture: a Qwen3-style causal LM (17 layers, hidden 512, vocab 8192) that autoregressively emits per-frame 512-dimensional features, and a non-iterative Vocos-style decoder (ConvNeXt backbone + single ISTFT head, n_fft 2048 / hop 512) that turns those features into 32 kHz audio.

Reference: https://github.com/ekwek1/soprano
Weights: https://huggingface.co/ekwek/Soprano-1.1-80M
GGUF packages: https://huggingface.co/WalkingCat/Soprano-1.1-80M-GGUF

Files added

Path	Purpose
src/community_models/soprano_tts/ (5 .cpp)	Assets, Qwen3 LM generator, Vocos decoder, tokenizer, session
include/engine/community_models/soprano_tts/ (5 .h)	Corresponding headers
model_specs/soprano_tts.json	Schema-v1 spec, community status, GGUF + safetensors sources
docs/soprano_tts.md	User-facing documentation
docs/soprano_validation.md	Validation record with build/run commands and timing
tests/soprano_tts/soprano_warm_bench.cpp	C++ warmbench binary
tests/soprano_tts/soprano_warm_bench_cases.txt	Warmbench test cases (short/medium/long/longform)
tests/soprano_tts/soprano_python_warm_bench.py	Python reference warmbench
tools/soprano_tts/convert_soprano.py	HF checkpoint converter (folds weight-norm)
tools/soprano_tts/run_official.py	Python reference inference runner
tools/soprano_tts/compare_parity.py	Automated validation harness

Files modified

File	Change
CMakeLists.txt	+16 lines: audiocpp_add_model + add_engine_warmbench
README.md	+2 lines: community table row
docs/gguf.md	+1 line: GGUF status table row
webui/configs/models_catalog.json	+1 line: WebUI catalog entry
webui/native/dist/index.html	Rebuilt frontend with Soprano baked in

Build

# Soprano only
cmake -B build -DCMAKE_BUILD_TYPE=Release \
  -DAUDIOCPP_MODEL_SET=custom -DAUDIOCPP_MODELS=soprano_tts
cmake --build build --target audiocpp_cli --parallel

# With Vulkan
cmake -B build -DCMAKE_BUILD_TYPE=Release \
  -DAUDIOCPP_MODEL_SET=custom -DAUDIOCPP_MODELS=soprano_tts \
  -DENGINE_ENABLE_VULKAN=ON
cmake --build build --target audiocpp_cli --parallel

Quick start

# Install GGUF package
python3 tools/model_manager_v2.py install soprano_1_1_80m_q8_0

# Run inference
build/bin/audiocpp_cli --task tts --family soprano_tts \
  --model models/Soprano-1.1-80M-GGUF/soprano-1.1-80m-q8_0.gguf \
  --text "Soprano is an extremely lightweight text to speech model." \
  --out soprano.wav

Run warmbench

# Build warmbench
cmake --build build --target soprano_warm_bench --parallel

# Run (CPU)
build/bin/soprano_warm_bench --model models/soprano_pkg \
  --output-dir build/logs/warmbench/soprano_tts

# Python reference
python3 tests/soprano_tts/soprano_python_warm_bench.py \
  --model models/Soprano-1.1-80M \
  --out-dir build/logs/warmbench/soprano_tts_py

Validation

CPU performance vs official Python soprano package (transformers backend, temp=0.3, top_p=0.95):

Test	Chars	Platform	Audio (s)	Infer (s)	RTF	Speedup
short	57	Python	0.752	1.281	1.7037	—
		C++	3.136	0.740	0.2360	7.22x
medium	152	Python	2.096	1.909	0.9106	—
		C++	8.320	1.955	0.2350	3.87x
long	567	Python	7.424	5.773	0.7776	—
		C++	16.384	4.302	0.2626	2.96x

Key observations:

• C++ RTF stays below 0.27 on all tests (faster than real-time).
• Audio durations differ between Python and C++ because of different RNG implementations; both produce valid 32 kHz speech.
• Backend coverage: CPU (tested, RTF ~0.24), Vulkan (tested on RX Vega, RTF ~0.08-0.12).
• See docs/soprano_validation.md for full validation record.

Known limitations

• English-only (model limitation)
• No voice cloning
• EOS sampling unreliable at low temperature (PyTorch vs C++ RNG difference)
• Full composite build may OOM; use AUDIOCPP_MODEL_SET=custom
• Vulkan decoder output has numerical drift on AMD RX Vega (no matrix-core ops)

Code and PR assisted and written by ox alpha(GLM 5.3 flash) and Deepseek v4 flash.

[drzsdrtfg]

pls let me know If there are any issues.