NeurIPS 2026 Papers

Editing a video stream in real time, without access to future frames, is essential for interactive applications. Existing training-free video editing methods, however, assume full offline access to the entire sequence, while streaming approaches either rely on additional training or are limited to specific editing techniques. We show that this limitation can be removed by analyzing the self-attention dynamics of DMD-distilled autoregressive video diffusion models. We uncover a key asymmetry: queries and keys remain stable and aligned with their source counterparts across denoising timesteps, while values diverge and encode the evolving content. This observation leads to a simple mechanism: a single forward pass suffices to capture source identity in the value features, which can be reused throughout generation. Starting from pure Gaussian noise and injecting only these source values reconstructs the input with fidelity matching inversion-based methods, effectively eliminating inversion. Based on this insight, we introduce AR-Edit, a training-free, inversion-free method that caches source values once and selectively injects them during autoregressive denoising, enabling real-time, structure-preserving streaming video editing with minimal overhead. Code will be released.

Current world models for explicit world simulation typically follow two distinct pathways: (1) video generative models (e.g., Sora), which simulate realistic appearances but fail to preserve 3D consistency; and (2) 3D generative models (e.g., Marble), which generate geometrically consistent scenes but often yield static, less realistic observations. We present AEON, a unified framework that bridges video-based and 3D-based world models and combines the benefits of both. The key insight of AEON lies in a generative model that operates within the video latent space while producing renderable 4D graphics primitives—specifically, 4D Gaussian Splatting (4DGS)—as the world modeler. We train a 4D reconstruction model to predict both 4DGS and camera poses from monocular videos, serving as our initialized 4D decoder. Furthermore, we design a domain adapter that translates generative video latents into reconstructive 4D latents through a distillation process on the video VAE. AEON naturally supports video-based world modeling by rendering 4DGS at predicted camera trajectories, and constructs a persistent 4D environment with scene dynamics for realistic world simulation. Consequently, AEON empowers a diverse range of world modeling applications and achieves state-of-the-art performance on standard benchmarks.

Multimodal large language models (MLLMs) have rapidly advanced machine intelligence by integrating visual perception with powerful linguistic reasoning. However existing visual backbones predominantly encode videos in a rigid per-frame manner and delegate temporal modeling entirely to the language model. This paradigm fundamentally constrains long-range temporal understanding and imposes severe computational inefficiencies. To resolve these bottlenecks we propose FuxViT, a unified Vision Transformer natively supporting a 64K-token context window to seamlessly process diverse inputs ranging from static images to hour-scale videos. By employing a joint spatiotemporal pretraining paradigm, FuxViT generates highly coherent and information-rich visual representations. This strategic early fusion frees the downstream language model from reconstructing low-level temporal structures to focus entirely on high-level reasoning. Furthermore we introduce Frame Selective Attention (FSA) as a native sparse routing mechanism. FSA dynamically attends to the most relevant historical frames to achieve exceptional computational efficiency without sacrificing fine-grained spatial or temporal details. Extensive experiments across 16 image and video benchmarks demonstrate that FuxViT consistently outperforms existing baselines and establishes itself as a vastly superior alternative to standard static ViTs for multimodal understanding. We will fully open-source all model checkpoints.

Video Moment Retrieval (VMR) aims to localize a temporal segment in a video based on a natural language query. While Multi-modal Large Language Models (MLLMs) are increasingly adopted for VMR due to their strong video understanding capability, they still face several limitations: (1) imprecise perception of event boundaries, (2) rigid dependency on precise object identification, and (3) inability to handle temporarily interrupted events. To address these, we propose three visual prompts: Event Segmentation (ES) prompt, Object Detection (OD) prompt, and Keyframe Marking (KM) prompt. Each prompt improves performance when applied individually, yet direct fusion degrades results because mixing prompts overcomplicates video content and inaccurate labels introduce noise. Although certain visual prompts may mislead the model, at least one of the three is likely to yield a positive effect. Even in the worst case where all three perform poorly, the prediction can fall back to the baseline. Motivated by this, we introduce a selection mechanism based on Yes/No Probability-Difference score to choose the most reliable prediction among the results produced by the three visual prompts and the baseline. We evaluate our method in a training-free setting across three datasets and four models, and obtain state-of-the-art performance.

Long-video understanding with multimodal LLMs is fundamentally constrained by the mismatch between video length and the model's limited visual context budget, making frame selection essential for practical reasoning. Existing query-aware methods typically rely on heuristic pipelines: they assign one-dimensional query-conditioned scores to frames and then apply sampling, ranking, or extraction rules to form the final subset. While effective in practice, such methods are generally not derived from an explicit optimization objective and struggle to capture the heterogeneous evidence required for complex reasoning. In this paper, we revisit long-video frame selection from a principled optimization perspective. We formulate it as a structured evidence-allocation problem and propose OTFS, an optimal transport framework that maps multiple evidence sources onto video frames. To reflect the asymmetry of this problem---important evidence should be preserved, whereas redundant frames need not absorb mass---we instantiate this view with a semi-unbalanced entropic optimal transport objective and an efficient solver, OTFS-Sinkhorn. Combined with an exact dynamic program for coverage-aware subset extraction, OTFS yields a practical two-stage training-free pipeline. We further show that, in the single-source case, our formulation induces a Gibbs-type distribution over frames, making Q-Frame's temperature-scaled distribution a special case of our framework while also providing a broader perspective for understanding related prior methods. Experiments on three long-video understanding benchmarks show that OTFS consistently outperforms strong training-free baselines. Code will be released.

The evolution of mathematics is shaped importantly by interestingness: researchers choose which problems to pursue, and students choose which problems to engage with, based on expectations of interest and challenge. As AI systems, particularly large language models (LLMs) that operate flexibly over natural language and formal mathematics, are increasingly used in mathematics research and education, it becomes crucial to characterize how closely their judgments align with people from different mathematical backgrounds. We study whether LLMs align with human interestingness judgments by comparing LLM ratings with those of two populations, crowdsourced participants with college math experience and International Math Olympiad competitors. Although many LLMs broadly agree with human notions of interestingness, they largely fail to match the distribution of human judgments. They also weakly align with why humans find problems interesting, with low correlation to human-selected rationales. Finally, we evaluate LLMs’ ability to generate interesting problems and find that, after filtering for validity, LLMs are able to generate engaging problems. We conclude with takeaways, including the need for multi-LLM human-AI collaborative systems, that highlight both the promise and current limits of LLMs as partners in mathematical reasoning.

While the maximal coding rate reduction (MCR$^2$) objective has become a useful principle for learning compact and discriminative representations, a theoretical understanding of its optimization geometry remains limited, especially on why first-order methods often exhibit fast convergence near its local maximizers. In this work, we show that the MCR$^2$ objective satisfies an error-bound property in a neighborhood of its local maximizers. This property guarantees that the distance to the local maximizer set can be bounded above by the gradient norm at any point in the neighborhood, directly implying regularity conditions such as the Polyak-Lojasiewicz inequality and quadratic growth. Leveraging this property, we prove that first-order methods converge linearly to a local maximizer of the MCR$^2$ objective under mild conditions. Numerical experiments validate the predicted local convergence behavior and provide empirical evidence that optimizing the MCR$^2$ objective improves representation geometry while maintaining competitive downstream accuracy.

AI video generation is evolving rapidly. For video generators to be useful for applications ranging from robotics to film-making, they must consistently produce realistic videos. However, evaluating the realism of generated videos remains a largely manual process -- requiring human annotation or bespoke evaluation datasets which have restricted scope. Here we develop an automated evaluation framework for video realism which captures both semantics and coherent 3D structure and which does not require access to a reference video. Our method, 3DSPA, is a **3D** **S**emantic **P**oint **A**utoencoder utoencoder which is trained to reconstruct held out 3D point trajectories which have been augmented with DINO semantic features. By combining both semantic and geometric representations, 3DSPA enables robust assessments of realism, temporal consistency, and physical plausibility in generated videos. Experiments show that 3DSPA outperforms leading VLMs by more than 10\% in identifying videos which violate physical laws, and more than doubles the correlations between human and auto-eval ratings in judging physical common sense and motion quality across multiple generative video datasets. Our results demonstrate that enriching trajectory-based representations with 3D semantics offers a strong foundation for benchmarking generative video models, and implicitly captures physical rule violations.