The Artifact Atlas
ManageableFixable with known levers.

Keyframe seams

A visible discontinuity exactly where two generated segments meet — the one moment in a clip when a viewer is already paying close attention.

Also called

  • Segment boundary artifact
  • Stitch line
  • Window seam
Evidence

PLACEHOLDER EVIDENCE. Replace with a clip showing a discontinuity at a segment boundary.

Causes
  1. 01Adjacent segments generated independently, each internally consistent, meeting at a hard boundary.
  2. 02Generation windows that abut rather than overlap, so no frames are shared to negotiate across.
  3. 03Anchor influence strongest at a segment's start, so the discontinuity lands at the join between a decayed end and a fresh beginning.
  4. 04Shot detection placing a boundary mid-motion, where continuity demands are highest.
  5. 05Per-segment colour or exposure normalisation that leaves each segment correct and neighbours mismatched.
What actually helps
  1. 01Overlap generation windows and blend across the shared frames instead of meeting at a hard edge.
  2. 02Place boundaries at genuine cuts or motion pauses, never mid-movement.
  3. 03Normalise colour and exposure across the whole sequence rather than per segment.
  4. 04Re-anchor at a shorter interval so no segment's end is running on decayed conditioning.
  5. 05Check boundaries specifically during review — they are predictable locations, so they can be checked deliberately.

Tends to originate at

  • Segment boundaries
  • Independent anchoring
  • Non-overlapping generation windows

How to confirm it

You already know where to look, which makes this the easiest artifact on the list to verify: seams only occur at segment boundaries. Get the boundary timecodes from the pipeline and step through those frames.

If the discontinuity is at a boundary, it is a seam. If it is somewhere else, it is something else — and that distinction saves a lot of wasted investigation.

Why it costs more than it looks like it should

A seam is usually a small error in absolute terms — a slight shift in colour, detail or position over one or two frames. It reads as disproportionately bad because of where it lands.

Cuts are where viewers re-orient. Attention spikes for a moment at every boundary, so an artifact there gets far more scrutiny than the same artifact would in the middle of a shot. The practical consequence: fixing a seam is often worth more than fixing a larger flaw elsewhere, and that runs against the instinct to prioritise by severity.

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