ATOS alpha surface: status ledger

Living document, updated 2026-08-13. What the alpha-fenced features have shipped, what has been validated, and what remains, in priority order. Companions: ROADMAP.md (methods under investigation), TESTING_ALPHA.md (how to exercise the alpha surface), TUNING.md (the operating doctrine).

Shipped and validated (alpha label still on)

Rolling-window regeneration (H3 Window Plan / H3 Window Collect, the requeue driver). Coverage defaults to the full clip so calm spans get the same second-pass repaint as the action; one-click batch queueing via the window widget's increment control; windows bank durably between queue items. Measured on a fenced 32 GB budget: the one-pass de-rope peaked at 30.7 GB and streamed the DiT layer by layer, two windows peaked at 22.5 / 24.6 GB with weights resident, at wall-time parity (440 s vs 460 s). Example validated end to end. To drop the alpha label: field reports from real 24 to 32 GB cards.
Arbitrary source video (H3 Video Fit): fits any clip to the 17k+5 grid with audio cut to match. First GPU executions 2026-08-13. The shipped example carries a placeholder filename by design.
Audio clock discipline: H3 Audio Recover retimes sample-exact against the world clock; splice and window collect place audio at absolute frame-derived offsets, so seams cannot accumulate error. Regression guard in tests/test_audio_recover.py (synthetic mode and a real-render file-pair mode). The 24 fps video vs 40 Hz audio-latent incommensurability is documented in TUNING with the aligned lengths (39 / 90 / 141 / 192 frames).
Cost readouts on the oracle, smear, and manual hold map: shipped; the minutes estimate is a ballpark and says so.

Rules minted this cycle (measured, envelopes stated in TUNING)

A turbo pass 1 tolerates only a SHALLOW turbo pass 2: 1 step at inject 0.20 held up in playback; 3 or 6 effective steps at 0.50 broke into mosaic on the same clip, while the identical recipe is clean over a bare 12-step pass 1. The init is the variable, not the recipe.
Pixel-space polish taps do not stack: every extra tap pays a VAE encode/decode roundtrip that costs more detail than a shallow solve returns. One tap is the recipe.
reference_mix defaults to 1.0, the pass-1 track intact.

Open, in priority order

Conditioning cache across windows. The text-encoder spike is what breaks small cards (21.2 GB resident vs 15.4 GB sustained, measured), and the requeue driver re-pays it per window for an unchanged prompt.
Per-token abstention. The shipped abstain_below gates the whole clip; window seam quality wants per-region abstain so cold cuts exist wherever the clip is genuinely calm.
Window driver bake-off. H3WindowLoop and H3WindowExpand have never rendered. Compare all three drivers on renders, cull to one.
Clock trim for exported clips. Concatenation outside this pack accumulates up to 12.5 ms of audio-length error per clip; a trim step on the way out closes it.
Cost model calibration. The superlinear per-step exponent was fitted at a single dilation; the exponent is untested elsewhere.
SAM-based subject targeting: NEXT UP (design reviewed 2026-08-13). Human-seeded subject selection driving the existing Manual Hold Map / Motion Composite / V2V freeze machinery, so "fix my subject, leave the background alone" stops requiring hand-drawn masks. Design review findings that now shape the build: (a) the first enabler is a TIME-VARYING freeze mask in H3 V2V Init, which today unions any mask over time into one static plane; the latent noise_mask is already shaped (1, 1, t_lat, h, w), so this is tractable; (b) any tracking state must name which clock its masks live on (world frames, dilated latent frames, or segment-local frames; three clocks are in play); (c) video segmenters' documented weak spot is thin fast-moving objects and long occlusions, exactly this tool's regime, so mid-clip re-seeding is a design requirement, not a fallback.
Adaptive compute / spatial foveation: the standing research thread. Per-step cost is superlinear in token count (measured exponent ~1.7), so genuine spatial token reduction pays more than proportionally. The spatial sibling of the rolling window. Probes will follow the same measure-then-mint loop as the temporal work.
Continuation and temporal-inpainting UX (product shape settled 2026-08-14). Three verbs: EXTEND a clip, ATTACH two clips, and HEAL the join, where healing is temporal inpainting with the de-rope as the repair pass. Masking (subject and region, item 6) and spatial upscaling ride along the same flows. Mechanism notes: core AddGuide anchors are the conditioning path; per-token clean-context masking (upstream PR #15375, merged 2026-08-18) is the pinning path the community evidence favors for seams; anchors obey the placement grid (multiples of 17 for clip guides, 39-frame overlaps); durations prefer the clock-aligned lengths (90 / 141 / 192). The clock discipline prerequisite is done.

Recently retired

Same-resolution audio-only repaint: at delivery resolution it costs the same as a quality video pass, and the video pass buys better pixels AND base-model audio. The low-resolution-conditioning variant (cheap full-step audio against a small pinned video) remains open.
LTX transfer experiment: deprioritized after weak first-pass community reports for extreme motion; the useful weights are parked for later low-motion upscaling work.