| --- |
| license: apache-2.0 |
| base_model: stepfun-ai/Step-Audio-EditX |
| library_name: mlx |
| pipeline_tag: audio-to-audio |
| language: |
| - en |
| - zh |
| tags: |
| - mlx |
| - speech-editing |
| - step-audio |
| - stepfun |
| - quantized |
| - 8bit |
| --- |
| |
| # Step-Audio-EditX — int8 MLX bundle |
|
|
| [Step-Audio-EditX](https://huggingface.co/stepfun-ai/Step-Audio-EditX) (StepFun, Apache-2.0): a 3 B audio LLM that |
| re-delivers an existing take — emotion, speaking style, inserted paralinguistics (laughter, sighs, breaths), denoise, |
| silence trim — in the same voice, plus zero-shot cloning. This is the |
| [bf16 bundle](https://huggingface.co/mlx-community/Step-Audio-EditX-bf16) with the **step1 LM quantised to 8 bits** |
| (affine, group 64, every Linear and the embeddings — `model.safetensors` 3.75 GB instead of 7.06 GB); the tokenizers, |
| flow, HiFT and CAM++ are the bf16 files unchanged. `config.json` carries |
| `"quantization": {"bits": 8, "group_size": 64, "mode": "affine"}`. |
|
|
| The quantised weights were written by the Swift consumer itself from the bf16 bundle (`editx-gates |
| --write-int8-bundle`, quantised on MLX's CPU stream), so loading this bundle reproduces quantise-at-load exactly. |
|
|
| | file | component | source | |
| |---|---|---| |
| | `model.safetensors` (3.75 GB, int8) + `config.json` | step1 LM — 32 × 3072, 48 heads / 4 KV groups, sqrt-ALiBi | `stepfun-ai/Step-Audio-EditX` | |
| | `vq02.safetensors`, `vq06.safetensors`, `step-audio-tokenizer-assets.safetensors` + configs | the dual tokenizer (bf16) | FunASR Paraformer (FunASR model licence) / `stepfun-ai/Step-Audio-Tokenizer` | |
| | `flow-model.safetensors`, `flow-conditioner.safetensors`, `hift.safetensors`, `campplus.safetensors` + configs | flow, vocoder, speaker (bf16) | StepFun-trained / Alibaba CAM++ (Apache-2.0) | |
| | `tokenizer.json`, `tokenizer_config.json`, `frontend-config.json` | text tokenizer, mel front end | derived from `tokenizer.model` | |
|
|
| ## Consumers |
|
|
| - **Swift**: [xocialize/mlx-step-audio-editx-swift](https://github.com/xocialize/mlx-step-audio-editx-swift) ≥ 0.1.1 — |
| `EditXPipeline.load(bundle:)` reads the quantisation from `config.json`. |
| - **Python**: `mlx-speech` loads int8 LM bundles of this layout (its `--bits 8` converter writes the same keys). |
|
|
| ## Measured (M5 Max, the Swift consumer, the E19 evaluation cues) |
|
|
| - Resident 6.2 GB phys_footprint after load (MLX active 5.7 GB); MLX peak 7.3–7.7 GB per edit; real-time factor |
| **0.51–0.53** (bf16: 0.72–0.75); loads in 0.5 s. |
| - Content survives every edit (ASR error 0.000 on the four test edits), speaker similarity 0.83–0.97 to the source, |
| DNSMOS 3.45–3.49 — the same bars as bf16 and the torch reference. Sampled tokens differ from bf16's at near-ties, |
| as any quantised tier's do. |
| |
| ## Licence |
| |
| Apache-2.0 (StepFun) for the LM, flow, HiFT and the S3 tokenizer; the Paraformer encoder under the FunASR model |
| licence; CAM++ Apache-2.0 (Alibaba / 3D-Speaker). Quantised and re-hosted by xocialize for mlx-community. |
| |
