Memorizon: Training World Models Beyond Their Context Window
TLDR
Memorizon trains streaming world models on arbitrarily long spans by retrieving top-K latents via camera co-visibility, enabling consistent repeated-visit rendering without quadratic attention cost.
Reasoning
The paper presents a novel training recipe that decouples long-span supervision from attention cost, with empirical evidence of improved revisit consistency and bounded step-time growth. Weaknesses include a trade-off with image quality and reliance on camera co-visibility, with no demonstrated interactive or RL settings.
Read-first score
Read-first score 34.1, weighted from topical fit, citation, graph, method, reproducibility, and recency signals. Original total remains 38.
Field roles
Rank sensitivity
Stability: volatile; rank range: 280.
Keyword Scores
Deep Analysis
Innovations
- Decouples long-span supervision from attention: training samples can cover arbitrary spans but are scored only on the last k chunks, so revisits can share a forward pass without including every intervening frame.
- Introduces a retrieval-based shared memory bank bounded by kK: each scored chunk retrieves its own top-K latents by camera co-visibility, and the union of these requests forms the bank, keeping sequence length bounded regardless of span.
- Scales training to long spans with minimal overhead: adding the bank raises step cost once, and extending span from 100 to 400 seconds adds only 12% step time.
Methodology
Memorizon trains streaming world models on samples that cover spans of any length but are scored only on the last k chunks. Each scored chunk retrieves top-K latents by camera co-visibility, and the union of these requests forms a shared bank bounded by kK. The approach is compared against a sliding-window baseline and evaluated on revisit consistency and image quality under varying span lengths and bank sources.
Key Results
Retrieval raises revisit consistency on every split over a sliding-window baseline. Spans long enough to reach the first visit of each return add a further 24% to 30% consistency but at some cost in image quality; beyond that span, more length no longer helps. Filling the bank from another episode lowers revisit correlation by 83%.
Limitations
- The gains in revisit consistency come at some cost in image quality.
- Extending the span beyond the first visit of each return does not further improve revisit consistency.