README.md

---
license: other
license_name: stability-ai-community-license
license_link: LICENSE.md
tags:
  - audio
  - text-to-audio
  - music-generation
  - allegretto-mini
  - onnx
  - onnxruntime
  - local-ai
  - generative-ai
library_name: onnxruntime
pipeline_tag: text-to-audio
---

# Allegretto Mini

**Allegretto Mini** is a lightweight, local-first AI music generation model developed by **OSAMA INC** (India). It synthesizes stereo audio at 44.1 kHz directly from text prompts — no cloud API, no server-side GPU required. Run it entirely on your own machine.

> 🤖 **HuggingFace Model**: [https://huggingface.co/Dev4285/Allegretto-Mini](https://huggingface.co/Dev4285/Allegretto-Mini)
> 💻 **GitHub**: [https://github.com/aryanisproinroblox-source/Allegretto-Mini](https://github.com/aryanisproinroblox-source/Allegretto-Mini)
> 🎧 **Live Demo**: [https://huggingface.co/spaces/Dev4285/Allegretto-Mini-Demo](https://huggingface.co/spaces/Dev4285/Allegretto-Mini-Demo) — try it right now in your browser!

## About OSAMA INC

**OSAMA INC** is an Indian AI research company building next-generation audio synthesis tools for creators, musicians, and developers. Allegretto Mini is our flagship release — a production-grade text-to-music model designed to run locally on consumer hardware, giving users full ownership of their creative workflow without dependency on external services.

| | |
|---|---|
| 🏢 **Company** | OSAMA INC (India) |
| 🎵 **Model** | Allegretto Mini |
| 🎧 **Output** | Stereo audio, 44.1 kHz |
| 💾 **Size** | ~640 MB (int4 quantized) |
| ⚡ **Default** | 10 seconds, 8 diffusion steps |
| 🔒 **License** | Stability AI Community License |

## Quick Start — Local Inference

Allegretto Mini uses ONNX Runtime so you can run inference locally on any machine — CPU or GPU — without Python or PyTorch dependencies. Just download the weights and go.

### Python (ONNX Runtime)

```python
import onnxruntime as ort
import numpy as np
from tokenizers import Tokenizer

# Load tokenizer and config
tokenizer = Tokenizer.from_file("tokenizer/tokenizer.json")
config = json.load(open("config.json"))

# Encode your text prompt
encoding = tokenizer.encode("upbeat electronic dance track with synth pads")
tokens = np.array([encoding.ids], dtype=np.int32)

# Create sessions
text_encoder = ort.InferenceSession("onnx/text_encoder_q4.onnx")
dit = ort.InferenceSession("onnx/dit_q4.onnx")
decoder = ort.InferenceSession("onnx/decoder_q4.onnx")

# Generate latent, run diffusion loop, decode to audio
# See the full pipeline in the examples directory
```

### JavaScript / Node.js

```js
const ort = require("onnxruntime-node");
const tokenizer = await Tokenizer.fromFile("tokenizer/tokenizer.json");

// Same pipeline — encode → condition → diffuse → decode
// Works in Node.js, Electron, or bundled for the web
```

## Model Architecture

Allegretto Mini is built on a three-stage generative pipeline:

1. **Text Encoder** — T5Gemma-based encoder processes your text prompt into rich conditioning embeddings (768-dim, 256 tokens + 1 duration embedding).
2. **DiT (Diffusion Transformer)** — A 20-layer transformer with cross-attention generates latent audio representations through an 8-step rectified-flow sampling loop.
3. **SAME-S Decoder** — Converts latents to stereo waveforms at 44.1 kHz with 2-channel output.

A lightweight **Number Conditioner** embeds the desired duration (in seconds) so you can control clip length at inference time.

While the underlying architecture draws from the same family as Stability AI's stable-audio-3-small, Allegretto Mini has been independently optimized, quantized, and packaged by OSAMA INC for efficient local deployment.

## Model Files

```
config.json                         Runtime configuration
number_conditioner.npz              Duration embedder weights
tokenizer/
  tokenizer.json                    T5Gemma tokenizer
  tokenizer_config.json             Tokenizer settings
onnx/
  text_encoder_q4.onnx              Text encoder graph (~213 MB weights)
  dit_q4.onnx                       Diffusion transformer graph (~380 MB weights)
  decoder_q4.onnx                   Audio decoder graph (~45 MB weights)
  number_conditioner.onnx           Duration embedder graph (~0.8 MB)
  *_chunks.json                     Weight manifest per graph
  *_chunk_*.data                    Quantized weight data (split ≤100 MB each)
```

Total download size: **~640 MB** of int4 quantized weights across 9 external data chunks.

## Inference Specs

- **Latent shape**: `(1, 256, T_lat)` where `T_lat = ceil((seconds + 6) * 44100 / 8192) * 2`
- **Cross-attention conditioning**: `(1, 257, 768)` — 256 text tokens + 1 duration embedding
- **Global conditioning (adaLN)**: `(1, 768)` — duration embedding
- **Output**: `(1, 2, T_lat * 4096)` — stereo audio at 44.1 kHz, values clamped to [-1, 1]
- **Default generation**: 10 seconds, 8 steps
- **CFG**: Disabled at inference time (`cfg_scale = 1.0`)

## Sampling

Allegretto Mini uses a rectified-flow denoiser with the **pingpong** sampler:

```
denoised = x - t_curr * dit(x, t_curr, conditioning)
x = (1 - t_next) * denoised + t_next * randn_like(x)
```

The schedule uses `LogSNRShift(rate=0, anchor_logsnr=-6.2, logsnr_end=2.0)` — a closed-form formula that works for any duration without recomputing the schedule. Fast, deterministic, and sequence-length-invariant.

## Performance

| Metric | Value |
|---|---|
| DiT q4 vs fp32 SNR | ~10 dB |
| Decoder q4 vs fp32 SNR | ~15 dB |
| Text encoder q4 vs fp32 SNR | ~13 dB |
| End-to-end envelope correlation | ≈ 0.88 |
| Local CPU (single thread) | ~60–120s per 10s clip |
| With GPU acceleration | Significantly faster |

Quantization uses **int4 MatMulNBits** (`block_size=16`) for weight-bearing nodes, **GatherBlockQuantized** for embedding tables, and fp32 for LayerNorm scales, biases, and Conv1d kernels — keeping quality high while slashing size to ~640 MB.

## License

This model is released under the **Stability AI Community License**. The T5Gemma encoder components additionally fall under Google's **Gemma Terms of Use**. Both license files are included in this repository; see `NOTICE` for combined attribution.

---

*Allegretto Mini — developed and released by OSAMA INC (India)*