Milimo AI Pipeline Expert Skill

As the Milimo AI Pipeline Expert, your domain covers the deeply integrated diffusion/transformer logic and VRAM management strategies for LTX-2, Flux 2, and the LLM enhancement endpoints.

Device & Memory Constraints (CRITICAL)

• Apple Silicon (MPS) is the primary assumed target environment, though CUDA is supported.
• The MemoryManager (memory_manager.py) strictly enforces mutual exclusion between LTX-2 and Flux 2 to prevent unified memory OOM crashes.
• Before loading LTX-2, you must call memory_manager.prepare_for("video").
• Before loading Flux 2, you must call memory_manager.prepare_for("image").
• MPS Bug Hacks: Flux and LTX VAE decoders must run in float32 on MPS, or they will output black frames. torch.mps.empty_cache() and gc.collect() must be manually executed between pipeline swaps.

LTX-2 Video Pipeline (model_engine.py & tasks/video.py)

• LTX-2 is a 19B Dual-Stream Transformer. The distillation checkpoint (ltx-2-19b-distilled) runs at 8 inference steps.
• Three Pipeline Types:
  1. ti2vid: Default Text/Image-to-Video. Replaces noisy latents at frame 0 with input image conditioning.
  2. ic_lora: Used for subject consistency.
  3. keyframe: Used for start-to-end frame interpolation.
• Prompt Enhancement: By default, user prompts are piped through llm.py before hitting the text encoder.

Chained Generation (tasks/chained.py)

• Standard LTX-2 supports max 505 frames.
• Chained gen uses autoregressive chunking (505 frames per chunk, 24 frame overlap).
• Quantum Alignment: Latent space is 8 pixels per token. The 24-pixel overlap is mathematically quantized into latent_slice_count. Trimming happens via ffmpeg -ss to perfectly match the latent splice point, preventing "frozen anchor" visual artifacts during transition.

Flux 2 Image & Inpainting (models/flux_wrapper.py)

• FluxInpainter Singleton: Holds the Flow model, AE, Qwen 3 text encoder, and CLIP ViT-L IP-Adapter.
• AE Hot-Swapping: Can toggle between the Native AutoEncoder (supports temporal reference offsets for image conditioning) and the diffusers wrapper fallback.
• Sequential True CFG: Flux 2 is distillation-guided, ignoring negative prompts. Milimo implements a custom 2-pass CFG loop inside denoise_inpaint() to restore negative prompt capability (at the cost of double inference time).
• Inpainting (RePaint): Uses mask interpolation merging x_pred and x_known at each timestep.

Ollama Coordination (llm.py)

• Prompts enhanced via local VLM running alongside generation.
• KEEP_ALIVE Management: To prevent VRAM lockout, llm.py appends keep_alive: 0 to Ollama requests based on user settings, explicitly unloading the language model before returning the enhanced text to the video caller.