TX-2.3 model fails to load with Diffusers - Missing model_index.json

#20
by sachin915t - opened

Description

The newly released Lightricks/LTX-2.3 model cannot be loaded using DiffusionPipeline.from_pretrained() because the repository structure lacks the required model_index.json file that Diffusers expects.

Error Reproduction

import torch
from diffusers import DiffusionPipeline

pipe = DiffusionPipeline.from_pretrained(
    "Lightricks/LTX-2.3", 
    torch_dtype=torch.bfloat16
)

Expected Behavior

Model should load successfully like other LTX-Video models (Lightricks/LTX-Video, Lightricks/LTX-Video-0.9.7-dev).

Actual Behavior

RemoteEntryNotFoundError: 404 Client Error.

Entry Not Found for url: https://huggingface.co/Lightricks/LTX-2.3/resolve/main/model_index.json

Environment

  • Diffusers version: 0.32.0
  • Python version: 3.12
  • Platform: Linux (Kaggle Notebook)

Model Repository Structure

The LTX-2.3 repo contains raw .safetensors files instead of Diffusers-compatible structure:

ltx-2.3-22b-dev.safetensors (46.1 GB)
ltx-2.3-22b-distilled.safetensors (46.1 GB)
ltx-2.3-22b-distilled-lora-384.safetensors (7.61 GB)
... (no model_index.json)

Possible Solutions

  1. Add Diffusers-compatible model_index.json to the repository
  2. Provide from_single_file() loading support in Diffusers
  3. Update documentation to clarify LTX-2.3 requires the official LTX-2 codebase instead of Diffusers

Additional Context

  • The model card mentions Diffusers support but the repository structure doesn't match
  • Other LTX-Video versions (0.9.5, 0.9.7) work correctly with Diffusers
  • Model was released ~January 2026

Labels: bug, model loading, LTX-Video


+1

Please update this, Lightricks.

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