packages/ltx-trainer/docs/training-guide.md

Training Guide

This guide covers how to run training jobs, from basic single-GPU training to advanced distributed setups and automatic model uploads.

⚡ Basic Training (Single GPU)

After preprocessing your dataset and preparing a configuration file, you can start training using the trainer script:

uv run python scripts/train.py configs/ltx2_av_lora.yaml

The trainer will:

1. Load your configuration and validate all parameters
2. Initialize models and apply optimizations
3. Run the training loop with progress tracking
4. Generate validation videos (if configured)
5. Save the trained weights in your output directory

Output Files

For LoRA training:

• lora_weights.safetensors - Main LoRA weights file
• training_config.yaml - Copy of training configuration
• validation_samples/ - Generated validation videos (if enabled)

For full model fine-tuning:

• model_weights.safetensors - Full model weights
• training_config.yaml - Copy of training configuration
• validation_samples/ - Generated validation videos (if enabled)

🖥️ Distributed / Multi-GPU Training

We use Hugging Face 🤗 Accelerate for multi-GPU DDP and FSDP.

Configure Accelerate

Run the interactive wizard once to set up your environment (DDP / FSDP, GPU count, etc.):

uv run accelerate config

This stores your preferences in ~/.cache/huggingface/accelerate/default_config.yaml.

Use the Provided Accelerate Configs (Recommended)

We include ready-to-use Accelerate config files in configs/accelerate/:

• ddp.yaml — Standard DDP
• ddp_compile.yaml — DDP with torch.compile (Inductor)
• fsdp.yaml — Standard FSDP (auto-wraps BasicAVTransformerBlock)
• fsdp_compile.yaml — FSDP with torch.compile (Inductor)

Launch with a specific config using --config_file:

# DDP (2 GPUs shown as example)
CUDA_VISIBLE_DEVICES=0,1 \
uv run accelerate launch --config_file configs/accelerate/ddp.yaml \
  scripts/train.py configs/ltx2_av_lora.yaml

# DDP + torch.compile
CUDA_VISIBLE_DEVICES=0,1 \
uv run accelerate launch --config_file configs/accelerate/ddp_compile.yaml \
  scripts/train.py configs/ltx2_av_lora.yaml

# FSDP (4 GPUs shown as example)
CUDA_VISIBLE_DEVICES=0,1,2,3 \
uv run accelerate launch --config_file configs/accelerate/fsdp.yaml \
  scripts/train.py configs/ltx2_av_lora.yaml

# FSDP + torch.compile
CUDA_VISIBLE_DEVICES=0,1,2,3 \
uv run accelerate launch --config_file configs/accelerate/fsdp_compile.yaml \
  scripts/train.py configs/ltx2_av_lora.yaml

Notes:

• The number of processes is taken from the Accelerate config (num_processes). Override with --num_processes X or restrict GPUs with CUDA_VISIBLE_DEVICES.
• The compile variants enable torch.compile with the Inductor backend via Accelerate's dynamo_config.
• FSDP configs auto-wrap the transformer blocks (fsdp_transformer_layer_cls_to_wrap: BasicAVTransformerBlock).

Launch with Your Default Accelerate Config

If you prefer to use your default Accelerate profile:

# Use settings from your default accelerate config
uv run accelerate launch scripts/train.py configs/ltx2_av_lora.yaml

# Override number of processes on the fly (e.g., 2 GPUs)
uv run accelerate launch --num_processes 2 scripts/train.py configs/ltx2_av_lora.yaml

# Select specific GPUs
CUDA_VISIBLE_DEVICES=0,1 uv run accelerate launch scripts/train.py configs/ltx2_av_lora.yaml

You can disable the in-terminal progress bars with --disable_progress_bars flag in the trainer CLI if desired.

Benefits of Distributed Training

• Faster training: Distribute workload across multiple GPUs
• Larger effective batch sizes: Combine gradients from multiple GPUs
• Memory efficiency: Each GPU handles a portion of the batch

Distributed training requires that all GPUs have sufficient memory for the model and batch size. The effective batch size becomes batch_size × num_processes.

🤗 Pushing Models to Hugging Face Hub

You can automatically push your trained models to the Hugging Face Hub by adding the following to your configuration:

hub:
  push_to_hub: true
  hub_model_id: "your-username/your-model-name"

Prerequisites

Before pushing, make sure you:

1. Have a Hugging Face account - Sign up at huggingface.co
2. Are logged in via huggingface-cli login or have set the HUGGING_FACE_HUB_TOKEN environment variable
3. Have write access to the specified repository (it will be created if it doesn't exist)

Login Options

Option 1: Interactive login

uv run huggingface-cli login

Option 2: Environment variable

export HUGGING_FACE_HUB_TOKEN="your_token_here"

What Gets Uploaded

The trainer will automatically:

• Create a model card with training details and sample outputs
• Upload model weights
• Push sample videos as GIFs in the model card
• Include training configuration and prompts

📊 Weights & Biases Logging

Enable experiment tracking with W&B by adding to your configuration:

wandb:
  enabled: true
  project: "ltx-2-trainer"
  entity: null  # Your W&B username or team
  tags: [ "ltx2", "lora" ]
  log_validation_videos: true

This will log:

• Training loss and learning rate
• Validation videos
• Model configuration
• Training progress

🚀 Next Steps

After training completes:

• Run inference with your trained LoRA - The ltx-pipelines package provides production-ready inference pipelines that support loading custom LoRAs. Available pipelines include text-to-video, image-to-video, IC-LoRA video-to-video, and more. See the ltx-pipelines package for usage details.
• Test your model with validation prompts
• Iterate and improve based on validation results
• Share your results by pushing to Hugging Face Hub

💡 Tips for Successful Training

• Start small: Begin with a small dataset and a few hundred steps to verify everything works
• Monitor validation: Keep an eye on validation samples to catch overfitting
• Adjust learning rate: Lower learning rates often produce better results
• Use gradient checkpointing: Essential for training with limited GPU memory
• Save checkpoints: Regular checkpoints help recover from interruptions

Need Help?

If you encounter issues during training, see the Troubleshooting Guide.

Join our Discord community for real-time help!