From Content to Knowledge: Lightning Fast Long-Video Understanding with Neural Knowledge Representations
Yuchen GuanXiao LiZongyu GuoXiaoyi ZhangXiulian PengChun YuanYan Lu
Introduces a framework that encodes long videos directly into lightweight neural network weights via agentic distillation, enabling frozen vision-language models to perform multi-turn video understanding while reducing inference latency by over two orders of magnitude.
Analyzing long-form video content using artificial intelligence is critical for automated monitoring, conversational assistants, and media analysis. However, conventional vision-language models struggle with videos that last for tens of minutes or hours. Current systems either feed massive sequences of video frames directly into models—creating severe memory bottlenecks and computation costs—or rely on iterative search agents that require minutes of planning and tool retrieval per question. These limitations prevent real-time, multi-turn interaction over long video archives.
The article demonstrates a new paradigm called Neural Knowledge Representation (NKR) to overcome these latency and memory constraints. The core objective is to evaluate whether a video's semantic content can be distilled offline into a compact, swappable set of neural network adapter weights, allowing a vision-language model to answer user queries instantly without reprocessing raw video files or searching external databases during runtime.
To achieve this, the authors developed an automated Agentic Knowledge Distillation pipeline that prepares training data without human annotation. An autonomous agent analyzes the video across multiple granularities to generate dense text descriptions alongside thousands of clip-level and video-level question-and-answer pairs. These synthetic data are then used in a one-time optimization phase to train a lightweight Low-Rank Adaptation (LoRA) module on a frozen foundation model backbone. The approach was evaluated on standard long-video benchmarks, notably LVBench (encompassing 103 videos totaling 117 hours and 1,549 questions), measuring accuracy, latency, and memory footprint against leading commercial models and agentic retrieval frameworks.
The findings show that NKR reduces query response latency by over two orders of magnitude compared to existing approaches. On the LVBench benchmark, the method achieved an inference speed of approximately 0.33 seconds per query, compared to 30 to 65 seconds for direct token processing and up to 180 seconds for agent-based discovery systems, while maintaining a competitive accuracy of 48.8%. Crucially, NKR incurs zero additional video memory overhead during inference because the adapter weights merge directly into the language model. Furthermore, while competing models suffered performance drops of 3.0% to 6.7% when processing videos exceeding one hour, the proposed representation remained remarkably stable, experiencing only a 0.3% degradation.
These results demonstrate that long-video understanding can be decoupled from raw video duration at inference time. For enterprise systems and interactive applications, this shift eliminates the need for expensive high-memory infrastructure and long user wait times during repeated querying. While heavy agentic models remain preferable for offline tasks requiring maximum forensic accuracy regardless of runtime, this adapter-based approach offers an optimal solution for real-time customer-facing assistants and fast interactive workflows.
Organizations handling extensive video repositories should consider piloting adapter-based neural representations for high-frequency interactive querying where latency is critical. Operational teams must account for the upfront processing trade-off: each one-hour video requires two to three hours of automated data synthesis and roughly two hours of offline training across specialized hardware before real-time querying becomes available.
Confidence in these findings is supported by consistent benchmark validations across both long video and complex image datasets. However, decision-makers should note certain limitations. The distillation process currently relies on text-based representations generated by automated agents, which can miss extremely subtle visual nuances that are hard to describe in text. Additionally, like all foundation model adaptations, the system remains subject to occasional factual hallucinations and requires reliable upfront compute for the initial encoding phase.
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