Vamba: Understanding Hour-Long Videos with Hybrid Mamba-Transformers
Authors: name: Weiming Ren; name: Wentao Ma; name: Huan Yang; name: Cong Wei; name: Ge Zhang; name: Wenhu Chen
Published: 2025-03-14 16:45:23

Abstract: State-of-the-art transformer-based large multimodal models (LMMs) struggle to
handle hour-long video inputs due to the quadratic complexity of the causal
self-attention operations, leading to high computational costs during training
and inference. Existing token compression-based methods reduce the number of
video tokens but often incur information loss and remain inefficient for
extremely long sequences. In this paper, we explore an orthogonal direction to
build a hybrid Mamba-Transformer model (VAMBA) that employs Mamba-2 blocks to
encode video tokens with linear complexity. Without any token reduction, VAMBA
can encode more than 1024 frames (640times360) on a single GPU, while
transformer-based models can only encode 256 frames. On long video input, VAMBA
achieves at least 50% reduction in GPU memory usage during training and
inference, and nearly doubles the speed per training step compared to
transformer-based LMMs. Our experimental results demonstrate that VAMBA
improves accuracy by 4.3% on the challenging hour-long video understanding
benchmark LVBench over prior efficient video LMMs, and maintains strong
performance on a broad spectrum of long and short video understanding tasks.