SolitaryThinker
a5be058cf1
Wire up and verify the Cosmos3 image-to-video path. The denoise stage already handled the I2V conditioning math (encode -> condition mask -> keep frame 0 clean -> velocity zeroed on condition frames, all matching the framework), but the conditioning pixel clip was built wrong. Bug: `_image_to_video_tensor` zero-filled every frame after frame 0. The framework (`cosmos_framework.inference.vision.build_conditioned_video_batch`) instead fills frame 0 with the image and **repeats the last conditioning frame** for the rest of the clip (a static video) before VAE-encoding. Because the Wan VAE is temporal (4x), latent frame 0 (the kept-clean condition frame) depends on several pixel frames, so zero-filling produces a wrong conditioning latent. Fix `_image_to_video_tensor` to be framework-faithful: - aspect-preserving resize + center crop + uint8 quantization, then `/127.5 - 1` (mirrors `load_conditioning_image` / `_resize_and_center_crop`); - static-repeat fill across all frames (mirrors `build_conditioned_video_batch`). Parity: add `test_cosmos3_i2v_conditioning_parity.py` comparing the FastVideo conditioning clip against the framework's `load_conditioning_image` + repeat-fill across aspect/size/frame-count cases — bit-exact (max abs diff 0.0). Example: `examples/inference/basic/basic_cosmos3_i2v_new_api.py` (new VideoGenerator API, image via `InputConfig(image_path=...)`, `assets/images/cyclist.jpg` default). Verified on B200 (1280x704, 29f, 35 steps, real weights): frame 0 reproduces the conditioning image and the clip generates coherent forward motion following the prompt. Full cosmos3 suite: 98 passed, 0 skipped.
Local Tests
Local-only parity, smoke, and component tests for FastVideo model ports. They compare FastVideo against the official reference implementations and are skipped in CI; run them locally on a single GPU (or CPU where noted).
For the CI-backed test suite, see fastvideo/tests/.
Layout
Tests are organized by model family, one directory per port. Each family
directory follows the layout produced by the
add-model-prep skill:
tests/local_tests/<family>/
├── README.md # reference assets, setup, test inventory
├── __init__.py
└── test_<family>_<component>_*.py
Families
| Family | Workload | Dir |
|---|---|---|
| Hunyuan GameCraft | T2V / I2V | gamecraft/ |
| GEN3C | T2V | gen3c/ |
| Kandinsky-5 | T2V | kandinsky5/ |
| LTX-2 | T2V (+ audio) | ltx2/ |
| Stable Diffusion 3.5 | T2I | sd35/ |
| Stable Audio Open 1.0 | T2A | stable_audio/ |
| Wan2.2 | I2V | wan22/ |
Running a family
pytest tests/local_tests/<family>/ -v -s
See each family's README.md for setup (clones, weights, env vars, gated
tokens) and the per-component parity coverage.
Adding a new family
Run the add-model-prep
skill from the FastVideo repo root. It scaffolds the family directory and
README.md and stages reference clones + weights. (In-progress ports may also
add a PORT_STATUS.md from the same skill template; remove it once the port
lands.)