Reported by the user: setting the shift sigma to 1 or 0 with restart 0 got them
nowhere, and what they wanted was "generate me a full video and don't make the 2nd
pass, just cut off the beginning".
That was a gap, not a crash. Both extremes fell through to the splitter, which
correctly refused (a cut at the first sigma leaves pass 1 no step; a cut at the last
leaves pass 2 none) and reported a skip — so anchor_shift silently did nothing and
the skip reason did not name the thing they were actually after.
anchor_shift_sigma=0 now means it: a cut at sigma 0 IS the end of the schedule, so
pass 1 is the entire run and there is nothing left to denoise. The scene samples
exactly as if anchor_shift were off — anchor pinned at full strength the whole way,
which is the point — and the slide is applied to the FINISHED latent. Zero extra
sampling: the cheapest form of this feature by a wide margin, and with tail=crop it
is plainly "generate the video, then delete the opening". Widget min lowered 0.05 -> 0.
Two things are refused rather than half-worked, each naming its fix:
- tail=extend_last / empty, because with no second pass a refilled tail is never
denoised — extend_last would freeze the last frame for anchor_shift_frames and
empty would leave an empty latent on screen. crop and wrap are pure rearrangements
of finished content, so both are allowed.
- a non-zero restart sigma, which has nothing to restart.
And anchor_shift_fresh_audio is forced off in this mode (reported, not silent):
resetting the audio with nothing left to regenerate it would just produce a silent
clip.
The old "schedule never reaches ..." skip reason now points at sigma=0 as the way to
run the whole schedule and only cut the head, so the next person hitting the extreme
is told what to set.
Suite at baseline: 22 pre-existing failures, 289 passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
