---
language:
- en
- de
- es
- fr
- ja
- ko
- zh
- it
- pt
library_name: diffusers
license: other
license_name: ltx-2-community-license-agreement
license_link: https://github.com/Lightricks/LTX-2/blob/main/LICENSE
pipeline_tag: image-to-video
arxiv: 2601.03233
tags:
- image-to-video
- text-to-video
- video-to-video
- image-text-to-video
- audio-to-video
- text-to-audio
- video-to-audio
- audio-to-audio
- text-to-audio-video
- image-to-audio-video
- image-text-to-audio-video
- ltx-2
- ltx-2-3
- ltx-video
- ltxv
- lightricks
- nvfp4
- quantized
- fp4me
pinned: true
demo: https://console.ltx.video/playground/
---

# 🎬 LTX-2.3 NVFP4 Quantized Models

> **Compress LTX-2.3 from 46GB → 13GB while maintaining *most* of the quality**

These are NVFP4 quantized variants of LTX-2.3, optimized for users with limited VRAM who still want high-quality video generation. Along with the models, I'm sharing **Comfy Bathroom** — a custom node suite designed specifically for using LoRAs with these heavily quantized models.

---

## 📦 Available Models

| Model | Size | Description |
|-------|------|-------------|
| `LTX-2.3-FP4` | ~21GB | Standard NVFP4 quantization |
| `LTX-2.3-FP4ME` | ~13GB | Mixed Extreme - Blocks 0, 47 in BF16; Block 1, 46 in FP8 |

## 📦 Coming Soon Models
| Model | Size | Description |
|-------|------|-------------|
| `LTX-2.3-FP4MEL` | ~15GB | Mixed Extreme LoRA-friendly |

> ⚠️ **Note:** FP4ME variants have known LoRA compatibility issues. Use the included Comfy Bathroom nodes for best results.

---

## 🚿 Comfy Bathroom — Custom Node Suite

**Comfy Bathroom** is a LoRA loading system designed to work with NVFP4 overly quantized models. It provides per-block weight control to avoid artifacts when using LoRAs on aggressively quantized models.

### Why "Bathroom"?

Because I made the FP4 models with **Comfy Kitchen**, and when something goes wrong in the kitchen... you end up in the bathroom. 🚽

### 🪥 Nodes Included

| Node | Icon | Description |
|------|------|-------------|
| **Toothbrush** | 🪥 | LoRA loader with built-in FP4 presets |
| **Mirror (Simple)** | 🪞 | Per-block on/off toggles |
| **Mirror (Fancy)** | 🪞 | Per-block 0.0-1.0 strength sliders |
| **Shower** | 🚿 | Quick preset applier |
| **Towel** | 🧾 | LoRA packet info display |
| **Bathroom Sink** | 🚰 | Stack multiple LoRAs with global strength |

---

## 🔧 How It Works

### The Problem

When using LoRAs on NVFP4 quantized models, certain transformer blocks cause artifacts:

- **Low blocks (0-10)** → Smoky/cloudy output (noise generation interference)
- **High blocks (40-47)** → Double vision/ghosting (detail alignment issues)
- **Middle blocks (11-39)** → Usually stable for LoRA injection

### The Solution

Comfy Bathroom applies intelligent weight curves to transformer blocks, ramping up LoRA strength gradually in early blocks and tapering down in late blocks.

### Built-in Presets

| Preset | Description | Best For |
|--------|-------------|----------|
| **FP4ME Light** | Gentle ramp up/down, block 1 OFF | Style LoRAs, general use |
| **FP4ME Heavy** | Aggressive taper to 0 at block 46 | Heavy style modifications |
| **FP4MEL Light** | Offset for BF16 blocks 1, 46 | FP4MEL model + style LoRAs |
| **FP4MEL Heavy** | Aggressive taper with BF16 safe zones | FP4MEL + content LoRAs |

### Weight Curve Visualization

```
FP4ME Light:
Block:  0   1   2   3   4   5   6   7   8   9  10  11 ... 39  40  41  42  43  44  45  46  47
Weight: 1.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1.0 1.0 ... 1.0 0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.5 1.0
        BF16 FP8  ←── RAMP UP ──→  FULL   ←────── TAPER DOWN ──→  FP8  BF16
```

---

## 📸 Example Workflow

![Comfy Bathroom Workflow](/static-proxy?url=https%3A%2F%2Fcdn-uploads.huggingface.co%2Fproduction%2Fuploads%2F698ec074a70d792a7df70f72%2FcYq6VYUx9EzTpmBnf-Vrz.png)

### Basic Usage

```
Toothbrush (LoRA + Preset) ──► Bathroom Sink ──► Model
                                    │
                              global_strength
```

### Advanced Usage

```
Toothbrush ──► Shower (swap preset) ──► Mirror (fine tune) ──► Bathroom Sink ──► Model
      │                                                              │
      └──────────────────────────────────────────────────────────────┘
                              Multiple LoRAs can be stacked
```

---

## 💡 Usage Tips

### For Style LoRAs (90% of use cases)
- Use **FP4ME Light** preset
- The base model already knows anatomy/structure
- LoRA only needs to affect the "style layer" (middle blocks)

### For Content LoRAs (specific characters, unusual anatomy)
- Try **FP4ME Heavy** preset
- May need to experiment with Mirror nodes for fine-tuning
- Content LoRAs teach new concepts → need more block coverage

### For Multiple LoRAs
- Connect multiple Toothbrush nodes to Bathroom Sink
- Use global_strength to scale everything together
- Individual LoRA strengths multiply with global

---

## 📋 Requirements

- ComfyUI (latest version recommended)
- `comfy_kitchen` (for NVFP4 model loading)
- BF16/FP16/FP8/FP4 capable GPU (known to work on 3xxx and above)
- 16GB+ VRAM recommended, seen people use it on 12GB

---

## 📁 Installation

1. Download model files to `ComfyUI/models/checkpoints/` *unless you have a working unet loader for ltx2.3
2. Install Comfy Bathroom:
   ```
   ComfyUI/custom_nodes/comfy_bathroom.py
   ```
3. Restart ComfyUI

---

## 🙏 Credits

- **LTX-2.3** by [Lightricks](https://github.com/Lightricks/LTX-2)
- **NVFP4 Quantization** via Modified Comfy Kitchen
- **Comfy Bathroom Nodes** written by GLM5 (Z.ai)

---

## 📜 License

This model is subject to the [LTX-2 Community License Agreement](https://github.com/Lightricks/LTX-2/blob/main/LICENSE).

---

*When your LoRA is full of artifacts, head to the Bathroom. 🚿*