MixCache/Chorus-family step-caching adapted to LTX2.3's distilled schedule.
On the near-pure-noise plateau (sigma >= threshold, default 0.975) the
transformer output barely changes, so compute the base-model forward once
and reuse it for the remaining plateau steps, skipping ~3-4 of 8 full
48-block forwards. Below threshold every step computes for real and the
cache drops, so structure formation is never approximated. Deterministic
given seed -> safe in Batch Training, no rating-diversity impact.
Installed innermost as a per-scene model_function_wrapper (existing
tag/strip leak hygiene) so guidance wrappers still post-process each step's
cached-or-fresh prediction. Cache keyed by (input.shape, cond_or_uncond).
Editor: plateau_cache + plateau_cache_threshold in Engine -> Experimental,
auto-wired via the sampler_inputs bridge (no backend/builder change).
Off by default, UNVALIDATED LIVE. (Chorus cross-variant reuse rejected --
would blur batch-rating diversity; FreeSpec dropped -- wrong topology.)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
