prolepsis — hindcast feedback field

source

processed

not yet processed

Load a clip, choose a temporal stance, then press process the whole clip to unlock the processed preview.

processing…

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speed loop

no source -- -- frames symmetric

Source

Drop a video anywhere to load. High-contrast edges, bold motion, and strong light yield the densest trails.

Temporal stance

anticipationtrail ahead

symmetricbloom both

waketrail behind

anticipation ↔ wake0.50

transient-aware anticipation

Wake is the old live behaviour. Anticipation runs the field backward so each event arrives with a precursor swarm. Symmetric blends both — zero-phase in time.

Process

decode fps width

trim start (s)0.00

trim end (s)0.00

even out exposure across clip

load a clip to estimate cost.

Export

MP4 preferred; falls back to WebM. Frames are pre-rendered, so export is deterministic.

liner notes — un-live

Every realtime effect is causal: its output at time t can depend only on frames at or before t. A live feedback smear can therefore only trail behind motion, and seeking has to wipe its buffer — the state can't be rebuilt from the middle. Prolepsis drops causality on purpose. It reads the clip end-to-end, then runs the same field with the time-arrow free: smears that bloom ahead of an event, symmetric zero-phase trails, and a scrubber where every frame is already correct — so seeking is instant and acausal instead of a reset. The live framesmear isn't deleted; it's kept as the degraded, causal variant of the clean offline thing.

anticipation: The field run backward in time. Each transient gets a precursor swarm ramping up to it — pre-echo as deliberate texture. The video cousin of pre-verb.
symmetric: Forward + backward passes combined: smear blooms into and out of each event. Bidirectional, zero-phase. The balance slider weights precursor against wake.
transient-aware: A pre-analysis pass scores how big each upcoming change is; precursor density scales with what's coming. Multi-pass measurement no live system can do.
even exposure: Global statistics: luminance normalized against the whole clip's mean rather than a running estimate. Brightness held steady across the piece.
memory decay: Reverb time. How long the feedback tail persists — now in either temporal direction — before dissolving.
new frame opacity: How aggressively each fresh frame inscribes over the buffer. Lower = longer smear.
flow X / Y: Drift direction of the feedback buffer per frame. In anticipation/symmetric the backward pass mirrors it, so precursors converge into the event.
feedback zoom / rotation: Room size and spin. Above 1 the buffer expands; rotation accumulates spiral vortex trails.
oscillation: Tape wow. Flow direction breathes sinusoidally — unstable, warping accumulation.
strobe: Gated reverb. Decay pulses between near-frozen and fast-fade, stamping discrete echoes.
hue drift / chroma split: Shimmer and chromatic aberration, baked per frame so playback stays a pure blit.
edge / light / softening: The inscription mask: which parts of each frame get written hardest into the buffer, and how much the buffer diffuses between writes.