StreamMem: Query-Agnostic KV Cache Memory for Streaming Video Understanding

ICLR 2026 Conference Submission13873 Authors

Keywords: Multimodal Large Language Models, Streaming Video Understanding, Language and Vision, Language Grounding

TL;DR: We propose StreamMem, a query-agnostic, fixed-size KV cache memory mechanism for streaming video understanding.

Abstract: Multimodal large language models (MLLMs) have made significant progress in visual-language reasoning, but their ability to efficiently handle long videos remains limited. Despite recent advances in long-context MLLMs, storing and attending to the key-value (KV) cache for long visual contexts incurs substantial memory and computational overhead. Existing visual compression methods require either encoding the entire visual context before compression or having access to the questions in advance, which is impractical for long video understanding and multi-turn conversational settings. In this work, we propose StreamMem, a query-agnostic KV cache memory mechanism for streaming video understanding. Specifically, StreamMem encodes new video frames in a streaming manner, compressing the KV cache using attention scores between visual tokens and generic query tokens, while maintaining a fixed-size KV memory to enable efficient question answering (QA) in memory-constrained, long-video scenarios. Evaluation on three long video understanding and two streaming video question answering benchmarks shows that StreamMem achieves state-of-the-art performance in query-agnostic KV cache compression and is competitive with query-aware compression approaches.

Primary Area: applications to computer vision, audio, language, and other modalities

Submission Number: 13873