# ChatBack AI Model Mirror

Stable mirrors of on-device AI models used by the [ChatBack](https://github.com/Chazzo2008/chatback) Android app.
All inference runs **100% locally on the user's device** — no data is sent to any server.

See [NOTICE.md](NOTICE.md) for full attribution and licensing.

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## Models

### Base Model (Required)

| Model | File | Size | License |
|-------|------|------|---------|
| **Gemma 3 1B-IT** (q4_block128, ekv4096, LiteRT) | `gemma3-1b/Gemma3-1B-IT_multi-prefill-seq_q4_block128_ekv4096.task` | ~556 MB | Gemma Terms of Use |

Powers all chatroom AI features: smart replies, tone warnings, draft assistant,
auto-translation, summarisation, and AI Chat (when no large model is activated).
True 4 096-token KV cache baked into the .task file. Fast, low-RAM (~2 GB+), GPU/NPU-accelerated via LiteRT.

### AI Chat Upgrade (Optional — requires base model)

| Model | File | Size | License |
|-------|------|------|---------|
| **Gemma 4 E2B-IT** (LiteRT) | `gemma4-e2b/gemma-4-E2B-it.litertlm` | ~2.5 GB | Gemma Terms of Use |
| **Gemma 4 E2B-IT Abliterated** (NSFW, LiteRT) | `gemma4-e2b/Gemma-4-E2B-it-abliterated.litertlm` | ~2.5 GB | Gemma Terms of Use |

Best AI Chat quality. Loaded only while AI Chat is open; base model restores
automatically when you leave AI Chat. Requires 3 GB+ RAM.
The abliterated variant has safety alignment removed and is only visible when
NSFW mode is enabled in the app.

### Text-to-Speech

| Model | Size | License |
|-------|------|---------|
| **Piper TTS** — Amy, Lessac, LibriTTS-R, Ryan, Joe (ONNX medium) | ~178 MB total | MIT |
| **Kokoro TTS** English v1.0 (q8f16 ONNX, 28 voices) | ~100 MB | Apache 2.0 |

Kokoro uses mixed int8-weight/float16-activation quantization for better audio quality
vs pure int8. The app uses its own Java IPA phonemizer — no espeak-ng dependency.

---

## Download URLs used by the app

```
# Base model
https://huggingface.co/Chazzo2008/chatback-ai-models/resolve/main/gemma3-1b/Gemma3-1B-IT_multi-prefill-seq_q4_block128_ekv4096.task

# Large model upgrade
https://huggingface.co/Chazzo2008/chatback-ai-models/resolve/main/gemma4-e2b/gemma-4-E2B-it.litertlm

# Large model — NSFW abliterated variant
https://huggingface.co/Chazzo2008/chatback-ai-models/resolve/main/gemma4-e2b/Gemma-4-E2B-it-abliterated.litertlm
```