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[2/4] Diffusion Quantized ckpt export (#810)
## What does this PR do? **Type of change:** New feature <!-- Use one of the following: Bug fix, new feature, new example, new tests, documentation. --> **Overview:** This MR adds HuggingFace checkpoint export support for LTX‑2 by treating TI2VidTwoStagesPipeline as a diffusion-like pipeline, exporting only the stage‑1 transformer (with QKV-fusion-enabled dummy inputs) and falling back to writing model.safetensors when save_pretrained isn’t available. It also preserves the original forward in DynamicModule patching (_forward_pre_dm) so downstream callers can still invoke the pre-patched forward implementation. **Changes** 1. Added the calibration & quantization support of the LTX2, even with FP8 precision. 2. Preserve original forward before `DynamicModule` patching: when patching forward, we now stash the pre-patched implementation in `self._forward_pre_dm` (once) so downstream code can still call the original forward, then re-bind forward to the class implementation. This is needed for the LTX2 FP8 calibration. 3. Added LTX‑2 HF export path: `export_hf_checkpoint()` now also treats ltx_pipelines.ti2vid_two_stages.TI2VidTwoStagesPipeline as a “diffusion-like” object and routes it through _export_diffusers_checkpoint() (import guarded; no hard dependency). 4. Generalized component discovery: introduced get_diffusion_components() (aliasing the old get_diffusers_components) to support non-diffusers pipelines; for LTX‑2 it returns only stage_1_transformer. 5. Enabled QKV fusion for LTX‑2 backbone: added a model-aware dummy forward generator (generate_diffusion_dummy_forward_fn) that builds minimal LTX Modality inputs (including correct timesteps broadcasting) so shared-input hooks can run and fuse QKV when applicable. 6. Export fallback for non-save_pretrained modules: when a component lacks save_pretrained (LTX‑2 transformer), export now writes model.safetensors + minimal config.json instead of pytorch_model.bin. Plans - [x] [1/4] Add the basic functionalities to support limited image models with NVFP4 + FP8, with some refactoring on the previous LLM code and the diffusers example. PIC: @jingyu-ml - [x] [2/4] Add support to more video gen models. PIC: @jingyu-ml - [ ] [3/4] Add test cases, refactor on the doc, and all related README. PIC: @jingyu-ml - [ ] [4/4] Add the final support to ComfyUI. PIC @jingyu-ml ## Usage <!-- You can potentially add a usage example below. --> ```bash python quantize.py --model ltx-2 --format fp4 --batch-size 64 --calib-size 1 --n-steps 40 --extra-param checkpoint_path=/home/scratch.omniml_data_2/jingyux/models/LTX-2/ltx-2-19b-dev-fp8.safetensors --extra-param distilled_lora_path=/home/scratch.omniml_data_2/jingyux/models/LTX-2/ltx-2-19b-distilled-lora-384.safetensors --extra-param spatial_upsampler_path=/home/scratch.omniml_data_2/jingyux/models/LTX-2/ltx-2-spatial-upscaler-x2-1.0.safetensors --extra-param gemma_root=/home/scratch.omniml_data_2/jingyux/models/LTX-2/gemma-3-12b-it-qat-q4_0-unquantized --extra-param fp8transformer=true --hf-ckpt-dir ./ltx2-nvfp4 ``` ## Testing <!-- Mention how have you tested your change if applicable. --> ## Before your PR is "*Ready for review*" <!-- If you haven't finished some of the above items you can still open `Draft` PR. --> - **Make sure you read and follow [Contributor guidelines](https://github.com/NVIDIA/Model-Optimizer/blob/main/CONTRIBUTING.md)** and your commits are signed. - **Is this change backward compatible?**: Yes <!--- If No, explain why. --> - **Did you write any new necessary tests?**:No - **Did you add or update any necessary documentation?**:No - **Did you update [Changelog](https://github.com/NVIDIA/Model-Optimizer/blob/main/CHANGELOG.rst)?**:No <!--- Only for new features, API changes, critical bug fixes or bw breaking changes. --> ## Additional Information <!-- E.g. related issue. --> <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit ## Release Notes * **New Features** * Added LTX-2 video model support with complete quantization and export pipeline integration * Introduced `--extra-param` CLI option for flexible model configuration and parameter passing * Enhanced export capabilities with broader diffusion model compatibility * **Chores** * Changed default model data type from Half to BFloat16 for improved numerical stability <sub>✏️ Tip: You can customize this high-level summary in your review settings.</sub> <!-- end of auto-generated comment: release notes by coderabbit.ai --> --------- Signed-off-by: Jingyu Xin <jingyux@nvidia.com> |