> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/automodel/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/automodel/_mcp/server.

# LTX-2.3

> Fine-tune and generate synchronized video and audio with LTX-2.3

[LTX-2.3](https://huggingface.co/Lightricks/LTX-2.3) is a text-to-video diffusion model from Lightricks. Its dual-stream transformer denoises video and audio latents together so generated clips can include synchronized sound.

|                  |                                                 |
| ---------------- | ----------------------------------------------- |
| **Task**         | Text-to-Video with Audio                        |
| **Architecture** | Dual-stream DiT (Flow Matching)                 |
| **HF Org**       | [Lightricks](https://huggingface.co/Lightricks) |

## Available Models

LTX-2.3 supports full-parameter and LoRA fine-tuning with synchronized video and audio.

## Example Recipes

| Recipe                                                                                                                                    | Description                                              |
| ----------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------- |
| [ltx2\_3\_t2v\_flow.yaml](https://github.com/NVIDIA-NeMo/Automodel/blob/main/examples/diffusion/finetune/ltx2_3_t2v_flow.yaml)            | Full fine-tuning with flow matching                      |
| [ltx2\_3\_t2v\_flow\_lora.yaml](https://github.com/NVIDIA-NeMo/Automodel/blob/main/examples/diffusion/finetune/ltx2_3_t2v_flow_lora.yaml) | Parameter-efficient LoRA fine-tuning                     |
| [generate\_ltx2.yaml](https://github.com/NVIDIA-NeMo/Automodel/blob/main/examples/diffusion/generate/configs/generate_ltx2.yaml)          | Generate video and mux the model's audio into the output |

## Prepare Video and Audio Data

Install the diffusion and media dependencies, then preprocess clips with a fixed frame count. LTX-2.3 samples video at 24 FPS and trims or pads each audio track to the matching duration.

```bash
uv sync --extra diffusion --extra diffusion-media
uv run python -m tools.diffusion.preprocessing_multiprocess video \
  --video_dir /path/to/videos \
  --output_dir /path/to/ltx2-cache \
  --processor ltx2 \
  --num_frames 121 \
  --output_format pt \
  --resolution_preset 512p \
  --caption_format sidecar
```

LTX-2.3 requires an explicit frame count of the form `8n+1`, such as 9, 89, or 121. Clips without an audio stream use silence while preserving the video and audio alignment contract.

## Fine-Tune LTX-2.3

Set `data.dataloader.cache_dir` and `checkpoint.checkpoint_dir` in the selected recipe, then launch one process per GPU.

```bash
uv run torchrun --nproc-per-node=8 \
  examples/diffusion/finetune/finetune.py \
  -c examples/diffusion/finetune/ltx2_3_t2v_flow.yaml
```

For LoRA, use the LoRA recipe instead:

```bash
uv run torchrun --nproc-per-node=8 \
  examples/diffusion/finetune/finetune.py \
  -c examples/diffusion/finetune/ltx2_3_t2v_flow_lora.yaml
```

Both recipes use `flow_matching.adapter_type: ltx2`. The adapter applies the same sampled noise level to the video and audio streams and combines their flow-matching losses.

## Generate Video with Audio

Point `model.checkpoint` at a consolidated full-fine-tuning checkpoint, or set `model.lora_weights` for a LoRA checkpoint.

```bash
uv run python examples/diffusion/generate/generate.py \
  -c examples/diffusion/generate/configs/generate_ltx2.yaml \
  --model.checkpoint /path/to/checkpoint
```

The generation command writes an MP4 and muxes the generated waveform into it. See the [Diffusion Fine-Tuning Guide](/recipes-e2e-examples/diffusion-fine-tuning) and [Diffusion Dataset Preparation](/datasets/diffusion-dataset) guide for shared training and dataset options.

## Hugging Face Model Cards

* [Lightricks/LTX-2.3](https://huggingface.co/Lightricks/LTX-2.3)
* [diffusers/LTX-2.3-Diffusers](https://huggingface.co/diffusers/LTX-2.3-Diffusers)