The 'loop' temporal style (in the style list since forever, but inert) now does
what WanVideoWrapper's Loop Args does for WAN: on eligible denoise steps the
packed latent is cyclically rolled along its temporal dim before the forward and
the prediction unrolled after, so the model repeatedly sees the video's seam
(last|first frame) as an interior frame pair at step-varying positions (van der
Corput sequence, reset per scene) and smooths it into a natural loop. Video and
audio streams roll by their own frame counts and stay time-aligned; denoise
masks roll in step, so i2v anchor per-token timesteps stay consistent.
Near-zero overhead: two clones + torch.roll per eligible step, no extra forward
passes. Rolls only below the near-noise plateau (nothing to smooth up there, and
the plateau step-cache stays valid). Calls carrying guides are left canonical —
keyframe_idxs pins appended guide frames to absolute positions inside the same
T range, so rolling them would corrupt; on guide-carrying scenes the roll is
inert and the run mechanism log says so.
Wiring: concrete style via the global build_enhancements path (innermost
relative to per-scene wrappers, as required — prediction-modifying wrappers see
canonical orientation only); auto director's funpack_temporal_loop via a tagged
per-scene wrapper on the Scene Chain sampler, installed below the guidance
stack. Editor already exposes 'loop' in the temporal style dropdown.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
