AI 终于能记住你上次看到的画面了
现在的 AI 生成视频,聊着聊着就忘了前面发生了什么——它把历史全塞在内存里,越聊越卡,最后只能二选一:要么记得久,要么反应快。这篇把记忆搬到了模型外面:像图书馆一样,只把当前视角需要的几页抽出来读,上下文永远不膨胀;同时换了个能看长片的老师来教,学生三步就能出图,不用额外调参。结果是在一张 H200 上,每 1.5 秒的画面 2.11 秒生成,还能连续生成不跑偏。它不是你明天就能用的产品,但这是『能陪你一直聊下去的 AI 世界』第一次有了靠谱的架构。
📄 原文摘要(英文)
Interactive world models must support persistent memory, responsive interaction, and long-horizon generation, yet these requirements place conflicting demands on the model. Maintaining history in the denoiser context or key-value cache incurs growing cost, forcing a trade-off between session length and retained memory, while low-latency interaction relies on few-step generation whose capabilities are bounded by its teacher. Evoke addresses both limitations by externalizing persistent world state and redesigning the teacher for long-horizon interactive generation. Scene geometry is maintained in an external, camera-indexed world state bank, from which only view-relevant information is retrieved, keeping the denoiser context bounded as the session grows. Rather than treating the teacher as a fixed generator, we design it for long-horizon supervision: its sparse attention combines chunk-wise grouping, retrieval of selected distant frames, and a linear-attention global state, yielding linear growth in memory and compute while enabling supervision over long horizons. Such supervision exposes content drift that stays locally plausible within short windows, while per-chunk conditioning enables prompt changes and event control throughout the sequence. A 30-second distribution-matching objective, applied under self-forced rollouts, transfers both capabilities to a three-step student that uses no classifier-free guidance, improving resistance to long-term drift while preserving responsive conditioning. With bounded context and recurrent external memory, Evoke supports open-ended, continuously evolving generation; on a single H200 at 384times 640, each 1.5,s chunk is generated in 2.11,s. As a three-step world model, Evoke achieves state-of-the-art performance on WBench while remaining competitive on VBench-Long and VBench-2.0.