HOT-Step-CPP StableStep Models

Model files for the StableStep post-processing feature of HOT-Step-CPP — a local AI music generation app. StableStep re-renders the instrumental of a generated track through Stable Audio 3 (SDEdit-style partial re-noising) to replace autoencoder fizz with real spectral detail, while vocals are separated, cleaned, and remixed untouched.

These files are converted derivatives of stabilityai/stable-audio-3-medium (diffusion transformer + SAME-L autoencoder + T5Gemma text encoder), exported to ONNX and GGUF for native C++ inference. No weights were fine-tuned; only format conversion and precision changes (BF16/F16 storage, fp32-sensitive tensors kept at F32) were applied.

The easiest way to use these is HOT-Step-CPP's built-in Model Manager (StableStep tab), which downloads the set you need and places files automatically.

Backends

In current testing on an RTX 5090 the GGML backend is both smaller and substantially faster than the ONNX/TensorRT path for this workload.

Manual install layout

Relative to your HOT-Step-CPP models/ directory:

models/
├── sa3-dit-BF16.gguf              ← GGML set (repo root files)
├── sa3-same-enc-F16.gguf
├── sa3-same-dec-F16.gguf
├── sa3-text-enc-BF16.gguf
└── onnx/sa3/
    ├── sa3-dit.onnx               ← ONNX set
    ├── sa3-dit.onnx.data
    ├── sa3-same_encoder.onnx
    ├── sa3-same_decoder.onnx
    ├── sa3-text_encoder.onnx
    ├── sa3-seconds_embedder.onnx
    ├── tokenizer.json             ← tokenizer files: required for BOTH backends
    ├── tokenizer_config.json
    └── special_tokens_map.json

License

These weights are derived from Stable Audio 3 and are distributed under the Stability AI Community License (see LICENSE-STABILITY-AI-COMMUNITY.md / NOTICE in this repo). In short: free for research, non-commercial, and commercial use by individuals and organizations with less than $1M in annual revenue; larger organizations require an enterprise license from Stability AI. By downloading these files you agree to those terms. HOT-Step-CPP presents this license for acceptance before downloading in-app.

Powered by Stability AI.

Acknowledgements

• Stability AI — Stable Audio 3 (DiT + SAME-L autoencoder)
• Google — T5Gemma text encoder (via the Stable Audio 3 release)
• Conversion + native inference: the HOT-Step-CPP project