LOCI: Spatial Linear Memory for Streaming World Models
TLDR
LOCI is a hybrid spatial-memory architecture for streaming video world models, combining key-value caches and camera-conditioned recurrent linear attention to reproduce revisited scenes with lower memory.
Reasoning
The paper introduces a novel hybrid memory design that integrates projective camera geometry into recurrent linear attention, with strong empirical results on a public benchmark and real recorded trajectories. However, the abstract provides limited detail on baselines, ablations, and limitations, and the connection to broader world-model terminology is only partially explicit.
Read-first score
Read-first score 31.6, weighted from topical fit, citation, graph, method, reproducibility, and recency signals. Original total remains 35.
Field roles
Rank sensitivity
Stability: volatile; rank range: 238.
Keyword Scores
Deep Analysis
Innovations
- Hybrid spatial-memory architecture that keeps both key-value cache and recurrent linear-attention memory
- Recurrent linear-attention memory with reads and writes conditioned on projective camera geometry
- Alternating transformer blocks: cache-backed attention over past observations in half of blocks, chunk-restricted attention plus recurrent memory in the other half
- Recurrent readouts flow into subsequent cache-backed blocks to supply queries with accumulated scene context
- Bounded bank of retained observations enabling constant-memory streaming of long videos
Methodology
LOCI is a transformer-based video world model evaluated on the public MIND memory benchmark and held-out recorded trajectories. It uses a hybrid design where half of transformer blocks maintain a key-value cache of past observations, while the other half restrict attention to the current chunk and are complemented by a recurrent linear-attention memory conditioned on projective camera geometry. Comparisons are made against representative world models and a same-recipe full-softmax model using faithfulness on revisited content and memory usage.
Key Results
LOCI reproduces revisited content more faithfully than representative world models and a same-recipe full-softmax model. With full history, it lowers peak memory at equal length by about 30% relative to full softmax, and with a bounded bank of retained observations it streams long videos at constant memory while remaining more faithful than full softmax under the same budget.