Per the user's reminder that these are OPTIONS, not defaults: second_pass_op is a
combo defaulting to "none", and nothing runs unless it is picked. The expensive one
is therefore not a tax on anything — it costs what it costs only when chosen.
- "sharpen": one forward of Lightricks' trained 2x LatentUpsampler, resampled straight
back to the original size. No video-model calls, so a fraction of a step; pass 2 then
re-denoises the sharpened latent, which is what makes it stick. Adds detail consistent
with what is there and CANNOT fix wrong structure — the same limit segmented
detailing's sharpen mode documents.
- "upscale_2x": same upsampler, result KEPT at 2x, so pass 2 runs at 4x the pixels and
the scene decodes at double resolution. 3-5x the second half's cost.
Reuses detailing.py's _run_upsampler / _downscale_to and its lazily-loaded upsampler
(same model, same detail_upsampler knob, "auto" downloads the official file) rather
than adding a second copy of any of it.
Ordering that matters: the op runs BEFORE the rewind re-noise, because sharpening a
latent that has just had noise added back sharpens the noise.
Two failure modes handled rather than left implicit:
- upscale_2x changes the latent resolution, so the chunk's i2v anchor and mask are the
wrong size. Rescaling them would be inventing an anchor, so the pin is dropped and
the scene report SAYS the pass runs unpinned and may drift from the reference image.
- A missing or throwing upsampler degrades to "second pass, no operation" with the
reason, instead of killing a whole montage over an optional sharpen.
Found while writing the tests: an unrecognised op name was validated only AFTER the
upsampler forward had already run, so a typo paid full price and then reported the
wrong reason. Name is checked first now.
Editor + Easy Gen get the combo under Engine > Experimental; verified live that it
renders with none/sharpen/upscale_2x and defaults to none. Suite at baseline: 22
pre-existing failures, 306 passing.
Not built: downscale-then-rescale (DeepShrink-shaped). It is not a between-passes op —
pass 1 itself has to run at reduced resolution, which means downscaling the chunk, its
mask and the anchor before pass 1, so it needs its own insertion point rather than
this hook.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
